Upgrade to ruff>=0.16.0 (#2857)

* ruff>=0.16.0

See https://astral.sh/blog/ruff-v0.16.0

* uv run ruff check . --fix --unsafe-fixes

* Ruff fixes by Claude Code Opus 5

.github/actions/setup-sqlite-version/action.yml

@@ -0,0 +1,39 @@
+name: "Setup SQLite version"
+description: "Build and activate a specific SQLite version from its amalgamation archive"
+inputs:
+  version:
+    description: "The SQLite version to install"
+    required: true
+  cflags:
+    description: "CFLAGS to use when compiling SQLite"
+    required: false
+    default: ""
+  skip-activate:
+    description: "Set to true to skip modifying the library path"
+    required: false
+    default: "false"
+  fallback-urls:
+    description: "Whitespace-separated fallback download URLs to try after sqlite.org"
+    required: false
+    default: ""
+outputs:
+  sqlite-location:
+    description: "Directory containing the compiled SQLite library"
+    value: ${{ steps.build.outputs.sqlite-location }}
+runs:
+  using: "composite"
+  steps:
+    - shell: bash
+      run: mkdir -p "$RUNNER_TEMP/sqlite-versions/downloads"
+    - uses: actions/cache@v6
+      with:
+        path: ${{ runner.temp }}/sqlite-versions/downloads
+        key: setup-sqlite-version-${{ inputs.version }}-amalgamation-v1
+    - id: build
+      shell: bash
+      run: bash "$GITHUB_ACTION_PATH/setup-sqlite-version.sh"
+      env:
+        SQLITE_VERSION: ${{ inputs.version }}
+        SQLITE_CFLAGS: ${{ inputs.cflags }}
+        SQLITE_SKIP_ACTIVATE: ${{ inputs.skip-activate }}
+        SQLITE_EXTRA_FALLBACK_URLS: ${{ inputs.fallback-urls }}

.github/actions/setup-sqlite-version/setup-sqlite-version.sh

@@ -0,0 +1,144 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+version_spec="${SQLITE_VERSION:?SQLITE_VERSION is required}"
+cflags="${SQLITE_CFLAGS:-}"
+skip_activate="${SQLITE_SKIP_ACTIVATE:-false}"
+extra_fallback_urls="${SQLITE_EXTRA_FALLBACK_URLS:-}"
+
+case "$version_spec" in
+  3.46 | 3.46.0)
+    sqlite_version="3.46.0"
+    sqlite_year="2024"
+    amalgamation_id="3460000"
+    builtin_fallback_urls="https://static.simonwillison.net/static/2026/sqlite-amalgamation-3460000.zip"
+    ;;
+  3.25 | 3.25.0)
+    sqlite_version="3.25.0"
+    sqlite_year="2018"
+    amalgamation_id="3250000"
+    builtin_fallback_urls="https://static.simonwillison.net/static/2026/sqlite-amalgamation-3250000.zip?v=1"
+    ;;
+  *)
+    echo "::error::Unsupported SQLite version '$version_spec'. Add its release year and amalgamation id to $GITHUB_ACTION_PATH/setup-sqlite-version.sh."
+    exit 1
+    ;;
+esac
+
+case "$(uname -s)" in
+  Linux)
+    library_name="libsqlite3.so.0"
+    library_path_var="LD_LIBRARY_PATH"
+    ;;
+  Darwin)
+    library_name="libsqlite3.dylib"
+    library_path_var="DYLD_LIBRARY_PATH"
+    ;;
+  *)
+    echo "::error::Unsupported platform $(uname -s)"
+    exit 1
+    ;;
+esac
+
+runner_temp="${RUNNER_TEMP:-}"
+if [ -z "$runner_temp" ]; then
+  runner_temp="$(mktemp -d)"
+fi
+
+filename="sqlite-amalgamation-${amalgamation_id}"
+official_url="https://www.sqlite.org/${sqlite_year}/${filename}.zip"
+download_dir="${runner_temp}/sqlite-versions/downloads"
+source_root="${runner_temp}/sqlite-versions/source"
+source_dir="${source_root}/${filename}"
+build_dir="${runner_temp}/sqlite-versions/build/${sqlite_version}"
+archive_path="${download_dir}/${filename}.zip"
+
+mkdir -p "$download_dir" "$source_root" "$build_dir"
+
+download_archive() {
+  local url
+  local candidate_path="${archive_path}.tmp"
+  local urls=("$official_url")
+
+  for url in $builtin_fallback_urls $extra_fallback_urls; do
+    urls+=("$url")
+  done
+
+  rm -f "$candidate_path"
+  for url in "${urls[@]}"; do
+    echo "Downloading SQLite ${sqlite_version} amalgamation from ${url}"
+    if curl \
+      --fail \
+      --location \
+      --show-error \
+      --retry 5 \
+      --retry-delay 2 \
+      --retry-max-time 180 \
+      --retry-all-errors \
+      --connect-timeout 20 \
+      --max-time 240 \
+      --output "$candidate_path" \
+      "$url"; then
+      mv "$candidate_path" "$archive_path"
+      return 0
+    fi
+
+    echo "::warning::Download failed from ${url}"
+    rm -f "$candidate_path"
+  done
+
+  echo "::error::Could not download SQLite ${sqlite_version} amalgamation"
+  return 1
+}
+
+if [ ! -f "${source_dir}/sqlite3.c" ]; then
+  if [ ! -f "$archive_path" ]; then
+    download_archive
+  fi
+
+  rm -rf "$source_dir"
+  unzip -q "$archive_path" -d "$source_root"
+fi
+
+if [ ! -f "${source_dir}/sqlite3.c" ]; then
+  echo "::error::Expected ${source_dir}/sqlite3.c after extracting ${archive_path}"
+  exit 1
+fi
+
+read -r -a cflag_args <<< "$cflags"
+
+echo "Compiling SQLite ${sqlite_version} to ${build_dir}/${library_name}"
+gcc \
+  -fPIC \
+  -shared \
+  "${cflag_args[@]}" \
+  "${source_dir}/sqlite3.c" \
+  "-I${source_dir}" \
+  -o "${build_dir}/${library_name}"
+
+if [ "$library_name" = "libsqlite3.so.0" ]; then
+  ln -sf "$library_name" "${build_dir}/libsqlite3.so"
+fi
+
+if [ -n "${GITHUB_OUTPUT:-}" ]; then
+  echo "sqlite-location=${build_dir}" >> "$GITHUB_OUTPUT"
+else
+  echo "sqlite-location=${build_dir}"
+fi
+
+case "$(printf '%s' "$skip_activate" | tr '[:upper:]' '[:lower:]')" in
+  true | 1 | yes)
+    echo "Skipping ${library_path_var} activation"
+    ;;
+  *)
+    existing_value="${!library_path_var:-}"
+    if [ -n "${GITHUB_ENV:-}" ]; then
+      if [ -n "$existing_value" ]; then
+        echo "${library_path_var}=${build_dir}:${existing_value}" >> "$GITHUB_ENV"
+      else
+        echo "${library_path_var}=${build_dir}" >> "$GITHUB_ENV"
+      fi
+    fi
+    echo "Added ${build_dir} to ${library_path_var}"
+    ;;
+esac

.github/workflows/deploy-latest.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Check out datasette
-      uses: actions/checkout@v6
+      uses: actions/checkout@v7
     - name: Set up Python
       uses: actions/setup-python@v6
       with:

.github/workflows/documentation-links.yml

@@ -1,16 +0,0 @@
-name: Read the Docs Pull Request Preview
-on:
-  pull_request:
-    types:
-      - opened
-
-permissions:
-  pull-requests: write
-
-jobs:
-  documentation-links:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: readthedocs/actions/preview@v1
-        with:
-          project-slug: "datasette"

.github/workflows/playwright.yml

@@ -0,0 +1,48 @@
+name: Playwright
+
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        browser: [chromium, firefox, webkit]
+    steps:
+    - uses: actions/checkout@v7
+    - name: Set up Python 3.14
+      uses: actions/setup-python@v6
+      with:
+        python-version: "3.14"
+        allow-prereleases: true
+        cache: pip
+        cache-dependency-path: pyproject.toml
+    - name: Cache uv
+      uses: actions/cache@v6
+      with:
+        path: ~/.cache/uv
+        key: ${{ runner.os }}-py3.14-uv-${{ hashFiles('pyproject.toml') }}
+        restore-keys: |
+          ${{ runner.os }}-py3.14-uv-
+    - name: Cache Playwright browsers
+      uses: actions/cache@v6
+      with:
+        path: ~/.cache/ms-playwright/
+        key: ${{ runner.os }}-playwright-${{ matrix.browser }}-${{ hashFiles('pyproject.toml') }}
+        restore-keys: |
+          ${{ runner.os }}-playwright-${{ matrix.browser }}-
+    - name: Install uv
+      run: python -m pip install uv
+    - name: Install dependencies
+      run: uv sync --group dev --group playwright
+    - name: Install ${{ matrix.browser }}
+      run: uv run --group dev --group playwright playwright install --with-deps ${{ matrix.browser }}
+    - name: Run Playwright tests
+      run: uv run --group dev --group playwright pytest tests/test_playwright.py --playwright --browser ${{ matrix.browser }}

.github/workflows/prettier.yml

@@ -10,8 +10,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Check out repo
-      uses: actions/checkout@v6
-    - uses: actions/cache@v5
+      uses: actions/checkout@v7
+    - uses: actions/cache@v6
       name: Configure npm caching
       with:
         path: ~/.npm

.github/workflows/publish.yml

@@ -14,7 +14,7 @@ jobs:
       matrix:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v6
       with:
@@ -35,7 +35,7 @@ jobs:
     permissions:
       id-token: write
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Set up Python
       uses: actions/setup-python@v6
       with:
@@ -56,7 +56,7 @@ jobs:
     needs: [deploy]
     if: "!github.event.release.prerelease"
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Set up Python
       uses: actions/setup-python@v6
       with:
@@ -92,7 +92,7 @@ jobs:
     needs: [deploy]
     if: "!github.event.release.prerelease"
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Build and push to Docker Hub
       env:
         DOCKER_USER: ${{ secrets.DOCKER_USER }}

.github/workflows/push_docker_tag.yml

@@ -13,7 +13,7 @@ jobs:
   deploy_docker:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Build and push to Docker Hub
       env:
         DOCKER_USER: ${{ secrets.DOCKER_USER }}

.github/workflows/spellcheck.yml

@@ -9,7 +9,7 @@ jobs:
   spellcheck:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Set up Python
       uses: actions/setup-python@v6
       with:

.github/workflows/stable-docs.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v6
+      uses: actions/checkout@v7
       with:
         fetch-depth: 0  # We need all commits to find docs/ changes
     - name: Set up Git user

.github/workflows/test-coverage.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Check out datasette
-      uses: actions/checkout@v6
+      uses: actions/checkout@v7
     - name: Set up Python
       uses: actions/setup-python@v6
       with:

.github/workflows/test-pyodide.yml

@@ -12,7 +12,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Set up Python 3.10
       uses: actions/setup-python@v6
       with:
@@ -20,7 +20,7 @@ jobs:
         cache: 'pip'
         cache-dependency-path: '**/pyproject.toml'
     - name: Cache Playwright browsers
-      uses: actions/cache@v5
+      uses: actions/cache@v6
       with:
         path: ~/.cache/ms-playwright/
         key: ${{ runner.os }}-browsers

.github/workflows/test-sqlite-support.yml

@@ -25,7 +25,7 @@ jobs:
           #"3.23.1" # 2018-04-10, before UPSERT
         ]
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v6
       with:
@@ -34,7 +34,7 @@ jobs:
         cache: pip
         cache-dependency-path: pyproject.toml
     - name: Set up SQLite ${{ matrix.sqlite-version }}
-      uses: asg017/sqlite-versions@71ea0de37ae739c33e447af91ba71dda8fcf22e6
+      uses: ./.github/actions/setup-sqlite-version
       with:
         version: ${{ matrix.sqlite-version }}
         cflags: "-DSQLITE_ENABLE_DESERIALIZE -DSQLITE_ENABLE_FTS5 -DSQLITE_ENABLE_FTS4 -DSQLITE_ENABLE_FTS3_PARENTHESIS -DSQLITE_ENABLE_RTREE -DSQLITE_ENABLE_JSON1"

.github/workflows/test.yml

@@ -9,10 +9,11 @@ jobs:
   test:
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v6
       with:

.github/workflows/tmate-mac.yml

@@ -10,6 +10,6 @@ jobs:
   build:
     runs-on: macos-latest
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Setup tmate session
       uses: mxschmitt/action-tmate@v3

.github/workflows/tmate.yml

@@ -11,7 +11,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - name: Setup tmate session
       uses: mxschmitt/action-tmate@v3
       env:

.gitignore

@@ -1,8 +1,12 @@
 build-metadata.json
 datasets.json
 
+.playwright-mcp
+
 scratchpad
 
+ignored/
+
 .vscode
 
 uv.lock
@@ -131,4 +135,4 @@ tests/*.dylib
 tests/*.so
 tests/*.dll
 
-.idea
+.idea

Justfile

@@ -11,16 +11,33 @@ export DATASETTE_SECRET := "not_a_secret"
 @test *options: init
   uv run pytest -n auto {{options}}
 
+# Install Playwright browser support, Chromium by default
+@playwright-install browser="chromium":
+  uv run --group playwright playwright install {{browser}}
+
+# Install all Playwright browsers used by the test suite
+@playwright-install-all:
+  uv run --group playwright playwright install chromium firefox webkit
+
+# Run Playwright tests, Chromium by default
+@playwright browser="chromium" *options:
+  uv run --group playwright pytest tests/test_playwright.py --playwright --browser {{browser}} {{options}}
+
+# Run Playwright tests against all supported browsers
+@playwright-all *options:
+  uv run --group playwright pytest tests/test_playwright.py --playwright --browser chromium --browser firefox --browser webkit {{options}}
+
 @codespell:
   uv run codespell README.md --ignore-words docs/codespell-ignore-words.txt
   uv run codespell docs/*.rst --ignore-words docs/codespell-ignore-words.txt
   uv run codespell datasette -S datasette/static --ignore-words docs/codespell-ignore-words.txt
   uv run codespell tests --ignore-words docs/codespell-ignore-words.txt
 
-# Run linters: black, ruff, cog
+# Run linters: black, ruff, prettier, cog
 @lint: codespell
   uv run black datasette tests --check
   uv run ruff check datasette tests
+  npm run prettier -- --check
   uv run cog --check README.md docs/*.rst
 
 # Apply ruff fixes

datasette/__init__.py

@@ -1,8 +1,14 @@
 from datasette.permissions import Permission  # noqa
 from datasette.version import __version_info__, __version__  # noqa
 from datasette.events import Event  # noqa
-from datasette.tokens import TokenHandler, TokenRestrictions  # noqa
-from datasette.utils.asgi import Forbidden, NotFound, Request, Response  # noqa
+from datasette.tokens import TokenHandler, TokenInvalid, TokenRestrictions  # noqa
+from datasette.utils.asgi import (  # noqa
+    Forbidden,
+    NotFound,
+    PayloadTooLarge,
+    Request,
+    Response,
+)
 from datasette.utils import actor_matches_allow  # noqa
 from datasette.views import Context  # noqa
 from .hookspecs import hookimpl  # noqa

datasette/_pytest_plugin.py

@@ -19,23 +19,38 @@ import weakref
 
 import pytest
 
-from datasette.app import Datasette
-
 _active_instances: contextvars.ContextVar[list | None] = contextvars.ContextVar(
     "datasette_active_instances", default=None
 )
 
-_original_init = Datasette.__init__
+_original_init = None
 
 
-def _tracking_init(self, *args, **kwargs):
-    _original_init(self, *args, **kwargs)
-    instances = _active_instances.get()
-    if instances is not None:
-        instances.append(weakref.ref(self))
+def _install_tracking():
+    # datasette.app is imported lazily here rather than at module level:
+    # as a pytest11 entry point this module is imported during pytest
+    # startup, before pytest-cov starts measuring, so a module-level
+    # import would drag in all of datasette and make every import-time
+    # line in the package invisible to coverage
+    global _original_init
+    if _original_init is not None:
+        return
+    from datasette.app import Datasette
+
+    _original_init = Datasette.__init__
+
+    def _tracking_init(self, *args, **kwargs):
+        _original_init(self, *args, **kwargs)
+        instances = _active_instances.get()
+        if instances is not None:
+            instances.append(weakref.ref(self))
+
+    Datasette.__init__ = _tracking_init
 
 
-Datasette.__init__ = _tracking_init
+def pytest_configure(config):
+    if _enabled(config):
+        _install_tracking()
 
 
 def pytest_addoption(parser):
@@ -74,7 +89,8 @@ def pytest_runtest_protocol(item, nextitem):
                 continue
             try:
                 ds.close()
-            except Exception as e:
+            except Exception as e:  # noqa: BLE001
+                # Surfaced as a pytest warning; teardown must not fail the run
                 item.warn(
                     pytest.PytestUnraisableExceptionWarning(
                         f"Error closing Datasette instance: {e!r}"

datasette/actor_auth_cookie.py

@@ -1,8 +1,10 @@
-from datasette import hookimpl
-from itsdangerous import BadSignature
-from datasette.utils import baseconv
 import time
 
+from itsdangerous import BadSignature
+
+from datasette import hookimpl
+from datasette.utils import baseconv
+
 
 @hookimpl
 def actor_from_request(datasette, request):

datasette/blob_renderer.py

@@ -1,8 +1,9 @@
-from datasette import hookimpl
-from datasette.utils.asgi import Response, BadRequest
-from datasette.utils import to_css_class
 import hashlib
 
+from datasette import hookimpl
+from datasette.utils import to_css_class
+from datasette.utils.asgi import BadRequest, Response
+
 _BLOB_COLUMN = "_blob_column"
 _BLOB_HASH = "_blob_hash"
 

datasette/cli.py

@@ -1,43 +1,45 @@
 import asyncio
-import uvicorn
-import click
-from click import formatting
-from click.types import CompositeParamType
-from click_default_group import DefaultGroup
 import functools
 import json
 import os
 import pathlib
-from runpy import run_module
 import shutil
-from subprocess import call
 import sys
 import textwrap
 import webbrowser
+from runpy import run_module
+from subprocess import call
+
+import click
+import uvicorn
+from click import formatting
+from click.types import CompositeParamType
+from click_default_group import DefaultGroup
+
 from .app import (
-    Datasette,
     DEFAULT_SETTINGS,
     SETTINGS,
     SQLITE_LIMIT_ATTACHED,
+    Datasette,
     pm,
 )
 from .inspect import inspect_tables
 from .utils import (
+    ConnectionProblem,
     LoadExtension,
+    SpatialiteConnectionProblem,
+    SpatialiteNotFound,
     StartupError,
+    StaticMount,
+    ValueAsBooleanError,
     check_connection,
     deep_dict_update,
     find_spatialite,
-    parse_metadata,
-    ConnectionProblem,
-    SpatialiteConnectionProblem,
     initial_path_for_datasette,
     pairs_to_nested_config,
+    parse_metadata,
     temporary_docker_directory,
     value_as_boolean,
-    SpatialiteNotFound,
-    StaticMount,
-    ValueAsBooleanError,
 )
 from .utils.sqlite import sqlite3
 from .utils.testing import TestClient
@@ -75,7 +77,7 @@ class Setting(CompositeParamType):
             # Datasette 1.0, we turn bare setting names into setting.name
             # Type checking for those older settings
             default = DEFAULT_SETTINGS[name]
-            name = "settings.{}".format(name)
+            name = f"settings.{name}"
             if isinstance(default, bool):
                 try:
                     return name, "true" if value_as_boolean(value) else "false"
@@ -171,7 +173,6 @@ async def inspect_(files, sqlite_extensions):
 @cli.group()
 def publish():
     """Publish specified SQLite database files to the internet along with a Datasette-powered interface and API"""
-    pass
 
 
 # Register publish plugins
@@ -578,27 +579,27 @@ def serve(
         # https://github.com/simonw/datasette/issues/2389
         deep_dict_update(config_data, settings_updates)
 
-    kwargs = dict(
-        immutables=immutable,
-        cache_headers=not reload,
-        cors=cors,
-        inspect_data=inspect_data,
-        config=config_data,
-        metadata=metadata_data,
-        sqlite_extensions=sqlite_extensions,
-        template_dir=template_dir,
-        plugins_dir=plugins_dir,
-        static_mounts=static,
-        settings=None,  # These are passed in config= now
-        memory=memory,
-        secret=secret,
-        version_note=version_note,
-        pdb=pdb,
-        crossdb=crossdb,
-        nolock=nolock,
-        internal=internal,
-        default_deny=default_deny,
-    )
+    kwargs = {
+        "immutables": immutable,
+        "cache_headers": not reload,
+        "cors": cors,
+        "inspect_data": inspect_data,
+        "config": config_data,
+        "metadata": metadata_data,
+        "sqlite_extensions": sqlite_extensions,
+        "template_dir": template_dir,
+        "plugins_dir": plugins_dir,
+        "static_mounts": static,
+        "settings": None,  # These are passed in config= now
+        "memory": memory,
+        "secret": secret,
+        "version_note": version_note,
+        "pdb": pdb,
+        "crossdb": crossdb,
+        "nolock": nolock,
+        "internal": internal,
+        "default_deny": default_deny,
+    }
 
     # Separate directories from files
     directories = [f for f in files if os.path.isdir(f)]
@@ -621,9 +622,7 @@ def serve(
                 conn.close()
             else:
                 raise click.ClickException(
-                    "Invalid value for '[FILES]...': Path '{}' does not exist.".format(
-                        file
-                    )
+                    f"Invalid value for '[FILES]...': Path '{file}' does not exist."
                 )
 
     # Check for duplicate files by resolving all paths to their absolute forms
@@ -684,7 +683,7 @@ def serve(
         client = TestClient(ds)
         request_headers = {}
         if token:
-            request_headers["Authorization"] = "Bearer {}".format(token)
+            request_headers["Authorization"] = f"Bearer {token}"
         cookies = {}
         if actor:
             cookies["ds_actor"] = client.actor_cookie(json.loads(actor))
@@ -719,9 +718,13 @@ def serve(
             path = run_sync(lambda: initial_path_for_datasette(ds))
             url = f"http://{host}:{port}{path}"
         webbrowser.open(url)
-    uvicorn_kwargs = dict(
-        host=host, port=port, log_level="info", lifespan="on", workers=1
-    )
+    uvicorn_kwargs = {
+        "host": host,
+        "port": port,
+        "log_level": "info",
+        "lifespan": "on",
+        "workers": 1,
+    }
     if uds:
         uvicorn_kwargs["uds"] = uds
     if ssl_keyfile:
@@ -885,7 +888,7 @@ async def check_databases(ds):
             )
         except ConnectionProblem as e:
             raise click.UsageError(
-                f"Connection to {database.path} failed check: {str(e.args[0])}"
+                f"Connection to {database.path} failed check: {e.args[0]!s}"
             )
     # If --crossdb and more than SQLITE_LIMIT_ATTACHED show warning
     if (
@@ -893,9 +896,5 @@ async def check_databases(ds):
         and len([db for db in ds.databases.values() if not db.is_memory])
         > SQLITE_LIMIT_ATTACHED
     ):
-        msg = (
-            "Warning: --crossdb only works with the first {} attached databases".format(
-                SQLITE_LIMIT_ATTACHED
-            )
-        )
+        msg = f"Warning: --crossdb only works with the first {SQLITE_LIMIT_ATTACHED} attached databases"
         click.echo(click.style(msg, bold=True, fg="yellow"), err=True)

datasette/column_types.py

@@ -6,19 +6,17 @@ class SQLiteType(Enum):
     INTEGER = "INTEGER"
     REAL = "REAL"
     BLOB = "BLOB"
-    NULL = "NULL"
+    NUMERIC = "NUMERIC"
 
     @classmethod
-    def from_declared_type(cls, declared_type: str | None) -> "SQLiteType | None":
+    def from_declared_type(cls, declared_type: str | None) -> "SQLiteType":
         if declared_type is None:
-            return cls.NULL
+            return cls.BLOB
 
         normalized = declared_type.strip().upper()
         if not normalized:
-            return cls.NULL
+            return cls.BLOB
 
-        if normalized == cls.NULL.value:
-            return cls.NULL
         if "INT" in normalized:
             return cls.INTEGER
         if any(token in normalized for token in ("CHAR", "CLOB", "TEXT")):
@@ -31,7 +29,7 @@ class SQLiteType(Enum):
         ):
             return cls.REAL
 
-        return None
+        return cls.NUMERIC
 
 
 class ColumnType:
@@ -66,14 +64,14 @@ class ColumnType:
         Return an HTML string to render this cell value, or None to
         fall through to the default render_cell plugin hook chain.
         """
-        return None
+        return
 
     async def validate(self, value, datasette):
         """
         Validate a value before it is written. Return None if valid,
         or a string error message if invalid.
         """
-        return None
+        return
 
     async def transform_value(self, value, datasette):
         """

datasette/csrf.py

@@ -40,12 +40,12 @@ def _origin_tuple(value):
     scheme = (parsed.scheme or "").lower()
     host = (parsed.hostname or "").lower()
     if not scheme or not host:
-        raise ValueError("missing scheme or host in {!r}".format(value))
+        raise ValueError(f"missing scheme or host in {value!r}")
     port = parsed.port  # may raise ValueError on bad ports
     if port is None:
         port = DEFAULT_PORTS.get(scheme)
     if port is None:
-        raise ValueError("unknown default port for scheme {!r}".format(scheme))
+        raise ValueError(f"unknown default port for scheme {scheme!r}")
     return scheme, host, port
 
 
@@ -125,9 +125,7 @@ class CrossOriginProtectionMiddleware:
                 return
             await self._forbid(
                 send,
-                "Sec-Fetch-Site was {!r}, expected 'same-origin' or 'none'".format(
-                    sec_fetch_site
-                ),
+                f"Sec-Fetch-Site was {sec_fetch_site!r}, expected 'same-origin' or 'none'",
             )
             return
 
@@ -141,11 +139,11 @@ class CrossOriginProtectionMiddleware:
         request_scheme = self._request_scheme(scope)
         try:
             origin_tuple = _origin_tuple(origin)
-            expected_tuple = _origin_tuple("{}://{}".format(request_scheme, host))
+            expected_tuple = _origin_tuple(f"{request_scheme}://{host}")
         except ValueError:
             await self._forbid(
                 send,
-                "Malformed Origin {!r} or Host {!r}".format(origin, host),
+                f"Malformed Origin {origin!r} or Host {host!r}",
             )
             return
 
@@ -155,7 +153,7 @@ class CrossOriginProtectionMiddleware:
 
         await self._forbid(
             send,
-            "Origin {!r} does not match Host {!r}".format(origin, host),
+            f"Origin {origin!r} does not match Host {host!r}",
         )
 
     def _request_scheme(self, scope):
@@ -163,7 +161,8 @@ class CrossOriginProtectionMiddleware:
             try:
                 if self.datasette.setting("force_https_urls"):
                     return "https"
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
+                # Settings may not be readable this early; fall back to the ASGI scheme
                 pass
         return scope.get("scheme") or "http"
 

datasette/database.py

@@ -1,33 +1,35 @@
 import asyncio
 import atexit
-from collections import namedtuple
 import inspect
 import os
-from pathlib import Path
 import queue
-import sqlite_utils
 import sys
 import tempfile
 import threading
 import uuid
+from collections import namedtuple
+from pathlib import Path
 
+import sqlite_utils
+
+from .inspect import inspect_hash
 from .tracer import trace
 from .utils import (
     call_with_supported_arguments,
     detect_fts,
     detect_primary_keys,
     detect_spatialite,
+    escape_sqlite,
     get_all_foreign_keys,
     get_outbound_foreign_keys,
     md5_not_usedforsecurity,
-    sqlite_timelimit,
     sqlite3,
-    table_columns,
+    sqlite_timelimit,
     table_column_details,
+    table_columns,
 )
 from .utils.sql_analysis import SQLAnalysis, analyze_sql_tables
 from .utils.sqlite import sqlite_hidden_table_names
-from .inspect import inspect_hash
 
 connections = threading.local()
 
@@ -98,9 +100,7 @@ class Database:
 
     def _check_not_closed(self):
         if self._closed:
-            raise DatasetteClosedError(
-                "Database {!r} has been closed".format(self.name)
-            )
+            raise DatasetteClosedError(f"Database {self.name!r} has been closed")
 
     def _remove_pending_execute_future(self, future):
         with self._pending_execute_futures_lock:
@@ -139,7 +139,7 @@ class Database:
         if write:
             extra_kwargs["isolation_level"] = "IMMEDIATE"
         if self.memory_name:
-            uri = "file:{}?mode=memory&cache=shared".format(self.memory_name)
+            uri = f"file:{self.memory_name}?mode=memory&cache=shared"
             conn = sqlite3.connect(
                 uri, uri=True, check_same_thread=False, **extra_kwargs
             )
@@ -192,21 +192,20 @@ class Database:
             write_thread.join(timeout=10)
             if write_thread.is_alive():
                 sys.stderr.write(
-                    "Datasette: write thread for {!r} did not exit within 10s\n".format(
-                        self.name
-                    )
+                    f"Datasette: write thread for {self.name!r} did not exit within 10s\n"
                 )
                 sys.stderr.flush()
         for future in pending_execute_futures:
             try:
                 future.result()
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
+                # Shutdown teardown - a failed pending write must not block close()
                 pass
         # Close anything still tracked in _all_file_connections
         for connection in self._all_file_connections:
             try:
                 connection.close()
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
                 pass
         self._all_file_connections = []
         # Drop per-thread cached read connections we can reach
@@ -218,13 +217,13 @@ class Database:
         if self._read_connection is not None:
             try:
                 self._read_connection.close()
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
                 pass
             self._read_connection = None
         if self._write_connection is not None:
             try:
                 self._write_connection.close()
-            except Exception:
+            except Exception:  # noqa: BLE001, S110
                 pass
             self._write_connection = None
         if self.is_temp_disk:
@@ -246,6 +245,7 @@ class Database:
         request=None,
         return_all=False,
         returning_limit=EXECUTE_WRITE_RETURNING_LIMIT,
+        transaction=True,
     ):
         self._check_not_closed()
         if returning_limit < 0:
@@ -258,7 +258,9 @@ class Database:
             )
 
         with trace("sql", database=self.name, sql=sql.strip(), params=params):
-            results = await self.execute_write_fn(_inner, block=block, request=request)
+            results = await self.execute_write_fn(
+                _inner, block=block, request=request, transaction=transaction
+            )
         return results
 
     async def execute_write_script(self, sql, block=True, request=None):
@@ -298,13 +300,14 @@ class Database:
 
     async def execute_isolated_fn(self, fn):
         self._check_not_closed()
-        # Open a new connection just for the duration of this function
+        # Open a new connection just for the duration of this function,
         # blocking the write queue to avoid any writes occurring during it
-        if self.ds.executor is None:
-            # non-threaded mode
-            isolated_connection = self.connect(write=True)
+        write = self.is_mutable
+
+        def _run():
+            isolated_connection = self.connect(write=write)
             try:
-                result = fn(isolated_connection)
+                return fn(isolated_connection)
             finally:
                 isolated_connection.close()
                 try:
@@ -312,10 +315,18 @@ class Database:
                 except ValueError:
                     # Was probably a memory connection
                     pass
-            return result
-        else:
-            # Threaded mode - send to write thread
-            return await self._send_to_write_thread(fn, isolated_connection=True)
+
+        if self.ds.executor is None:
+            # non-threaded mode
+            return _run()
+        if not write:
+            # Immutable database - no writes can ever occur, so there is no
+            # write queue to block; run against a fresh read-only connection
+            return await asyncio.get_running_loop().run_in_executor(
+                self.ds.executor, _run
+            )
+        # Threaded mode - send to write thread
+        return await self._send_to_write_thread(fn, isolated_connection=True)
 
     async def analyze_sql(self, sql, params=None) -> SQLAnalysis:
         self._check_not_closed()
@@ -339,6 +350,7 @@ class Database:
                 self.ds._prepare_connection(self._write_connection, self.name)
             if transaction:
                 with self._write_connection:
+                    self._write_connection.execute("BEGIN IMMEDIATE")
                     result = fn(self._write_connection)
             else:
                 result = fn(self._write_connection)
@@ -357,7 +369,8 @@ class Database:
             async def _dispatch_events_after_write():
                 try:
                     await reply_future
-                except Exception:
+                except Exception:  # noqa: BLE001
+                    # The write failed; skip success events regardless of why
                     # if the write failed, don't emit success events
                     return
                 for event in pending_events:
@@ -410,9 +423,7 @@ class Database:
             self._write_thread = threading.Thread(
                 target=self._execute_writes, daemon=True
             )
-            self._write_thread.name = "_execute_writes for database {}".format(
-                self.name
-            )
+            self._write_thread.name = f"_execute_writes for database {self.name}"
             self._write_thread.start()
         task_id = uuid.uuid5(uuid.NAMESPACE_DNS, "datasette.io")
         loop = asyncio.get_running_loop()
@@ -433,7 +444,8 @@ class Database:
         try:
             conn = self.connect(write=True)
             self.ds._prepare_connection(conn, self.name)
-        except Exception as e:
+        except Exception as e:  # noqa: BLE001
+            # Stored and re-raised to whoever queues the next write
             conn_exception = e
         while True:
             task = self._write_queue.get()
@@ -441,7 +453,8 @@ class Database:
                 if conn is not None:
                     try:
                         conn.close()
-                    except Exception:
+                    except Exception:  # noqa: BLE001, S110
+                        # Best-effort close as the write thread exits
                         pass
                 return
             exception = None
@@ -449,29 +462,32 @@ class Database:
             if conn_exception is not None:
                 exception = conn_exception
             elif task.isolated_connection:
-                isolated_connection = self.connect(write=True)
                 try:
-                    result = task.fn(isolated_connection)
-                except Exception as e:
-                    sys.stderr.write("{}\n".format(e))
+                    isolated_connection = self.connect(write=True)
+                    try:
+                        result = task.fn(isolated_connection)
+                    finally:
+                        isolated_connection.close()
+                        try:
+                            self._all_file_connections.remove(isolated_connection)
+                        except ValueError:
+                            # Was probably a memory connection
+                            pass
+                except Exception as e:  # noqa: BLE001
+                    # Write thread must survive any task failure or the database wedges
+                    sys.stderr.write(f"{e}\n")
                     sys.stderr.flush()
                     exception = e
-                finally:
-                    isolated_connection.close()
-                    try:
-                        self._all_file_connections.remove(isolated_connection)
-                    except ValueError:
-                        # Was probably a memory connection
-                        pass
             else:
                 try:
                     if task.transaction:
                         with conn:
+                            conn.execute("BEGIN IMMEDIATE")
                             result = task.fn(conn)
                     else:
                         result = task.fn(conn)
-                except Exception as e:
-                    sys.stderr.write("{}\n".format(e))
+                except Exception as e:  # noqa: BLE001
+                    sys.stderr.write(f"{e}\n")
                     sys.stderr.flush()
                     exception = e
             _deliver_write_result(task, result, exception)
@@ -538,9 +554,7 @@ class Database:
                         raise QueryInterrupted(e, sql, params)
                     if log_sql_errors:
                         sys.stderr.write(
-                            "ERROR: conn={}, sql = {}, params = {}: {}\n".format(
-                                conn, repr(sql), params, e
-                            )
+                            f"ERROR: conn={conn}, sql = {sql!r}, params = {params}: {e}\n"
                         )
                         sys.stderr.flush()
                     raise
@@ -593,7 +607,7 @@ class Database:
             try:
                 table_count = (
                     await self.execute(
-                        f"select count(*) from (select * from [{table}] limit {self.count_limit + 1})",
+                        f"select count(*) from (select * from {escape_sqlite(table)} limit {self.count_limit + 1})",
                         custom_time_limit=limit,
                     )
                 ).rows[0][0]
@@ -697,9 +711,9 @@ class Database:
             column_names
             and len(column_names) == 2
             and ("id" in column_names or "pk" in column_names)
-            and not set(column_names) == {"id", "pk"}
+            and set(column_names) != {"id", "pk"}
         ):
-            return [c for c in column_names if c not in ("id", "pk")][0]
+            return next(c for c in column_names if c not in ("id", "pk"))
         # Couldn't find a label:
         return None
 
@@ -819,10 +833,10 @@ def _apply_write_wrapper(fn, wrapper_factory, track_event):
         # Execute the actual write
         try:
             result = fn(conn)
-        except Exception:
+        except Exception as e:
             # Throw exception into generator so it can handle it
             try:
-                gen.throw(*sys.exc_info())
+                gen.throw(e)
             except StopIteration:
                 pass
             # Re-raise the original exception
@@ -841,10 +855,10 @@ def _apply_write_wrapper(fn, wrapper_factory, track_event):
 class WriteTask:
     __slots__ = (
         "fn",
-        "task_id",
+        "isolated_connection",
         "loop",
         "reply_future",
-        "isolated_connection",
+        "task_id",
         "transaction",
     )
 
@@ -885,7 +899,7 @@ class QueryInterrupted(Exception):
         self.params = params
 
     def __str__(self):
-        return "QueryInterrupted: {}".format(self.e)
+        return f"QueryInterrupted: {self.e}"
 
 
 class MultipleValues(Exception):

datasette/default_actions.py

@@ -2,8 +2,8 @@ from datasette import hookimpl
 from datasette.permissions import Action
 from datasette.resources import (
     DatabaseResource,
-    TableResource,
     QueryResource,
+    TableResource,
 )
 
 
@@ -61,6 +61,12 @@ def register_actions():
             description="Create tables",
             resource_class=DatabaseResource,
         ),
+        Action(
+            name="create-view",
+            abbr="cv",
+            description="Create views",
+            resource_class=DatabaseResource,
+        ),
         Action(
             name="store-query",
             abbr="sq",
@@ -111,6 +117,12 @@ def register_actions():
             description="Drop tables",
             resource_class=TableResource,
         ),
+        Action(
+            name="drop-view",
+            abbr="dv",
+            description="Drop views",
+            resource_class=TableResource,
+        ),
         # Query-level actions (child-level)
         Action(
             name="view-query",

datasette/default_column_types.py

@@ -76,6 +76,12 @@ class JsonColumnType(ColumnType):
         return None
 
 
+class TextareaColumnType(ColumnType):
+    name = "textarea"
+    description = "Multiline text"
+    sqlite_types = (SQLiteType.TEXT,)
+
+
 @hookimpl
 def register_column_types(datasette):
-    return [UrlColumnType, EmailColumnType, JsonColumnType]
+    return [UrlColumnType, EmailColumnType, JsonColumnType, TextareaColumnType]

datasette/default_debug_menu.py

@@ -37,6 +37,11 @@ DEBUG_MENU_ITEMS = (
         "Debug allow rules",
         "Explore how allow blocks match actors against permission rules.",
     ),
+    (
+        "/-/debug/autocomplete",
+        "Debug autocomplete",
+        "Try out table autocomplete against a detected label column.",
+    ),
     (
         "/-/threads",
         "Debug threads",

datasette/default_magic_parameters.py

@@ -1,8 +1,9 @@
-from datasette import hookimpl
 import datetime
 import os
 import time
 
+from datasette import hookimpl
+
 
 def header(key, request):
     key = key.replace("_", "-").encode("utf-8")

datasette/default_permissions/__init__.py

@@ -17,18 +17,29 @@ UNION/INTERSECT operations. The order of evaluation is:
 
 from __future__ import annotations
 
-# Re-export all hooks and public utilities
-from .restrictions import (
-    actor_restrictions_sql as actor_restrictions_sql,
-    restrictions_allow_action as restrictions_allow_action,
-    ActorRestrictions as ActorRestrictions,
-)
-from .root import root_user_permissions_sql as root_user_permissions_sql
 from .config import config_permissions_sql as config_permissions_sql
+from .defaults import (
+    DEFAULT_ALLOW_ACTIONS as DEFAULT_ALLOW_ACTIONS,
+)
+from .defaults import (
+    default_action_permissions_sql as default_action_permissions_sql,
+)
 from .defaults import (
     # Avoid "datasette.default_permissions" does not explicitly export attribute
     default_allow_sql_check as default_allow_sql_check,
-    default_action_permissions_sql as default_action_permissions_sql,
-    default_query_permissions_sql as default_query_permissions_sql,
-    DEFAULT_ALLOW_ACTIONS as DEFAULT_ALLOW_ACTIONS,
 )
+from .defaults import (
+    default_query_permissions_sql as default_query_permissions_sql,
+)
+from .restrictions import (
+    ActorRestrictions as ActorRestrictions,
+)
+
+# Re-export all hooks and public utilities
+from .restrictions import (
+    actor_restrictions_sql as actor_restrictions_sql,
+)
+from .restrictions import (
+    restrictions_allow_action as restrictions_allow_action,
+)
+from .root import root_user_permissions_sql as root_user_permissions_sql

datasette/default_permissions/config.py

@@ -6,7 +6,7 @@ Applies permission rules from datasette.yaml configuration.
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Any, List, Optional, Set, Tuple
+from typing import TYPE_CHECKING, Any
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -55,8 +55,8 @@ class ConfigPermissionProcessor:
 
     def __init__(
         self,
-        datasette: "Datasette",
-        actor: Optional[dict],
+        datasette: Datasette,
+        actor: dict | None,
         action: str,
     ):
         self.datasette = datasette
@@ -74,8 +74,8 @@ class ConfigPermissionProcessor:
         self.restrictions = actor.get("_r", {}) if actor else {}
 
         # Pre-compute restriction info for efficiency
-        self.restricted_databases: Set[str] = set()
-        self.restricted_tables: Set[Tuple[str, str]] = set()
+        self.restricted_databases: set[str] = set()
+        self.restricted_tables: set[tuple[str, str]] = set()
 
         if self.has_restrictions:
             self.restricted_databases = {
@@ -92,16 +92,20 @@ class ConfigPermissionProcessor:
             # Tables implicitly reference their parent databases
             self.restricted_databases.update(db for db, _ in self.restricted_tables)
 
-    def evaluate_allow_block(self, allow_block: Any) -> Optional[bool]:
+    def evaluate_allow_block(self, allow_block: Any) -> bool | None:
         """Evaluate an allow block against the current actor."""
         if allow_block is None:
             return None
+        # Values passed using ``-s permissions.* 1`` or ``0`` are parsed as
+        # integers, but should retain the CLI's boolean 1/0 behavior.
+        if isinstance(allow_block, int) and allow_block in (0, 1):
+            return bool(allow_block)
         return actor_matches_allow(self.actor, allow_block)
 
     def is_in_restriction_allowlist(
         self,
-        parent: Optional[str],
-        child: Optional[str],
+        parent: str | None,
+        child: str | None,
     ) -> bool:
         """Check if resource is allowed by actor restrictions."""
         if not self.has_restrictions:
@@ -143,9 +147,9 @@ class ConfigPermissionProcessor:
 
     def add_permissions_rule(
         self,
-        parent: Optional[str],
-        child: Optional[str],
-        permissions_block: Optional[dict],
+        parent: str | None,
+        child: str | None,
+        permissions_block: dict | None,
         scope_desc: str,
     ) -> None:
         """Add a rule from a permissions:{action} block."""
@@ -165,8 +169,8 @@ class ConfigPermissionProcessor:
 
     def add_allow_block_rule(
         self,
-        parent: Optional[str],
-        child: Optional[str],
+        parent: str | None,
+        child: str | None,
         allow_block: Any,
         scope_desc: str,
     ) -> None:
@@ -198,8 +202,8 @@ class ConfigPermissionProcessor:
 
     def _add_restriction_gate_denies(
         self,
-        parent: Optional[str],
-        child: Optional[str],
+        parent: str | None,
+        child: str | None,
         is_allowed: bool,
         scope_desc: str,
     ) -> None:
@@ -231,7 +235,7 @@ class ConfigPermissionProcessor:
                     if db_name == parent:
                         self.collector.add(db_name, table_name, False, reason)
 
-    def process(self) -> Optional[PermissionSQL]:
+    def process(self) -> PermissionSQL | None:
         """Process all config rules and return combined PermissionSQL."""
         self._process_root_permissions()
         self._process_databases()
@@ -421,10 +425,10 @@ class ConfigPermissionProcessor:
 
 @hookimpl(specname="permission_resources_sql")
 async def config_permissions_sql(
-    datasette: "Datasette",
-    actor: Optional[dict],
+    datasette: Datasette,
+    actor: dict | None,
     action: str,
-) -> Optional[List[PermissionSQL]]:
+) -> list[PermissionSQL] | None:
     """
     Apply permission rules from datasette.yaml configuration.
 

datasette/default_permissions/defaults.py

@@ -6,7 +6,7 @@ Provides default allow rules for standard view/execute actions.
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -29,29 +29,28 @@ DEFAULT_ALLOW_ACTIONS = frozenset(
 
 @hookimpl(specname="permission_resources_sql")
 async def default_allow_sql_check(
-    datasette: "Datasette",
-    actor: Optional[dict],
+    datasette: Datasette,
+    actor: dict | None,
     action: str,
-) -> Optional[PermissionSQL]:
+) -> PermissionSQL | None:
     """
     Enforce the default_allow_sql setting.
 
     When default_allow_sql is false (the default), execute-sql is denied
     unless explicitly allowed by config or other rules.
     """
-    if action == "execute-sql":
-        if not datasette.setting("default_allow_sql"):
-            return PermissionSQL.deny(reason="default_allow_sql is false")
+    if action == "execute-sql" and not datasette.setting("default_allow_sql"):
+        return PermissionSQL.deny(reason="default_allow_sql is false")
 
     return None
 
 
 @hookimpl(specname="permission_resources_sql")
 async def default_action_permissions_sql(
-    datasette: "Datasette",
-    actor: Optional[dict],
+    datasette: Datasette,
+    actor: dict | None,
     action: str,
-) -> Optional[PermissionSQL]:
+) -> PermissionSQL | None:
     """
     Provide default allow rules for standard view/execute actions.
 
@@ -71,10 +70,10 @@ async def default_action_permissions_sql(
 
 @hookimpl(specname="permission_resources_sql")
 async def default_query_permissions_sql(
-    datasette: "Datasette",
-    actor: Optional[dict],
+    datasette: Datasette,
+    actor: dict | None,
     action: str,
-) -> Optional[PermissionSQL]:
+) -> PermissionSQL | None:
     actor_id = actor.get("id") if isinstance(actor, dict) else None
 
     if action not in {"view-query", "update-query", "delete-query"}:

datasette/default_permissions/helpers.py

@@ -5,7 +5,7 @@ Shared helper utilities for default permission implementations.
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, List, Optional, Set
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -13,7 +13,7 @@ if TYPE_CHECKING:
 from datasette.permissions import PermissionSQL
 
 
-def get_action_name_variants(datasette: "Datasette", action: str) -> Set[str]:
+def get_action_name_variants(datasette: Datasette, action: str) -> set[str]:
     """
     Get all name variants for an action (full name and abbreviation).
 
@@ -27,7 +27,7 @@ def get_action_name_variants(datasette: "Datasette", action: str) -> Set[str]:
     return variants
 
 
-def action_in_list(datasette: "Datasette", action: str, action_list: list) -> bool:
+def action_in_list(datasette: Datasette, action: str, action_list: list) -> bool:
     """Check if an action (or its abbreviation) is in a list."""
     return bool(get_action_name_variants(datasette, action).intersection(action_list))
 
@@ -36,8 +36,8 @@ def action_in_list(datasette: "Datasette", action: str, action_list: list) -> bo
 class PermissionRow:
     """A single permission rule row."""
 
-    parent: Optional[str]
-    child: Optional[str]
+    parent: str | None
+    child: str | None
     allow: bool
     reason: str
 
@@ -46,14 +46,14 @@ class PermissionRowCollector:
     """Collects permission rows and converts them to PermissionSQL."""
 
     def __init__(self, prefix: str = "row"):
-        self.rows: List[PermissionRow] = []
+        self.rows: list[PermissionRow] = []
         self.prefix = prefix
 
     def add(
         self,
-        parent: Optional[str],
-        child: Optional[str],
-        allow: Optional[bool],
+        parent: str | None,
+        child: str | None,
+        allow: bool | None,
         reason: str,
         if_not_none: bool = False,
     ) -> None:
@@ -62,7 +62,7 @@ class PermissionRowCollector:
             return
         self.rows.append(PermissionRow(parent, child, allow, reason))
 
-    def to_permission_sql(self) -> Optional[PermissionSQL]:
+    def to_permission_sql(self) -> PermissionSQL | None:
         """Convert collected rows to a PermissionSQL object."""
         if not self.rows:
             return None

datasette/default_permissions/restrictions.py

@@ -8,7 +8,7 @@ contains allowlists of resources the actor can access.
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, List, Optional, Set, Tuple
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -23,12 +23,12 @@ from .helpers import action_in_list, get_action_name_variants
 class ActorRestrictions:
     """Parsed actor restrictions from the _r key."""
 
-    global_actions: List[str]  # _r.a - globally allowed actions
+    global_actions: list[str]  # _r.a - globally allowed actions
     database_actions: dict  # _r.d - {db_name: [actions]}
     table_actions: dict  # _r.r - {db_name: {table: [actions]}}
 
     @classmethod
-    def from_actor(cls, actor: Optional[dict]) -> Optional["ActorRestrictions"]:
+    def from_actor(cls, actor: dict | None) -> ActorRestrictions | None:
         """Parse restrictions from actor dict. Returns None if no restrictions."""
         if not actor:
             return None
@@ -44,11 +44,11 @@ class ActorRestrictions:
             table_actions=restrictions.get("r", {}),
         )
 
-    def is_action_globally_allowed(self, datasette: "Datasette", action: str) -> bool:
+    def is_action_globally_allowed(self, datasette: Datasette, action: str) -> bool:
         """Check if action is in the global allowlist."""
         return action_in_list(datasette, action, self.global_actions)
 
-    def get_allowed_databases(self, datasette: "Datasette", action: str) -> Set[str]:
+    def get_allowed_databases(self, datasette: Datasette, action: str) -> set[str]:
         """Get database names where this action is allowed."""
         allowed = set()
         for db_name, db_actions in self.database_actions.items():
@@ -57,8 +57,8 @@ class ActorRestrictions:
         return allowed
 
     def get_allowed_tables(
-        self, datasette: "Datasette", action: str
-    ) -> Set[Tuple[str, str]]:
+        self, datasette: Datasette, action: str
+    ) -> set[tuple[str, str]]:
         """Get (database, table) pairs where this action is allowed."""
         allowed = set()
         for db_name, tables in self.table_actions.items():
@@ -70,10 +70,10 @@ class ActorRestrictions:
 
 @hookimpl(specname="permission_resources_sql")
 async def actor_restrictions_sql(
-    datasette: "Datasette",
-    actor: Optional[dict],
+    datasette: Datasette,
+    actor: dict | None,
     action: str,
-) -> Optional[List[PermissionSQL]]:
+) -> list[PermissionSQL] | None:
     """
     Handle actor restriction-based permission rules.
 
@@ -140,10 +140,10 @@ async def actor_restrictions_sql(
 
 
 def restrictions_allow_action(
-    datasette: "Datasette",
+    datasette: Datasette,
     restrictions: dict,
     action: str,
-    resource: Optional[str | Tuple[str, str]],
+    resource: str | tuple[str, str] | None,
 ) -> bool:
     """
     Check if restrictions allow the requested action on the requested resource.

datasette/default_permissions/root.py

@@ -6,7 +6,7 @@ Grants full permissions to the root user when --root flag is used.
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -17,9 +17,9 @@ from datasette.permissions import PermissionSQL
 
 @hookimpl(specname="permission_resources_sql")
 async def root_user_permissions_sql(
-    datasette: "Datasette",
-    actor: Optional[dict],
-) -> Optional[PermissionSQL]:
+    datasette: Datasette,
+    actor: dict | None,
+) -> PermissionSQL | None:
     """
     Grant root user full permissions when --root flag is used.
     """

datasette/default_permissions/tokens.py

@@ -7,7 +7,7 @@ to datasette.verify_token() so all registered handlers are tried.
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from datasette.app import Datasette
@@ -17,15 +17,13 @@ from datasette.tokens import SignedTokenHandler
 
 
 @hookimpl
-def register_token_handler(datasette: "Datasette"):
+def register_token_handler(datasette: Datasette):
     """Register the default signed token handler."""
     return SignedTokenHandler()
 
 
 @hookimpl(specname="actor_from_request")
-async def actor_from_signed_api_token(
-    datasette: "Datasette", request
-) -> Optional[dict]:
+async def actor_from_signed_api_token(datasette: Datasette, request) -> dict | None:
     """
     Authenticate requests using API tokens by delegating to all registered
     token handlers via datasette.verify_token().

datasette/default_query_actions.py

@@ -0,0 +1,48 @@
+from datasette import hookimpl
+from datasette.resources import QueryResource
+
+
+@hookimpl
+def query_actions(datasette, actor, database, query_name, request):
+    # Only stored queries (with a name) can be edited or deleted
+    if not query_name:
+        return None
+
+    async def inner():
+        query = await datasette.get_query(database, query_name)
+        if query is None:
+            return []
+        # Config-defined and trusted queries are managed outside the UI
+        if query.source == "config" or query.is_trusted:
+            return []
+
+        links = []
+        if await datasette.allowed(
+            action="update-query",
+            resource=QueryResource(database, query_name),
+            actor=actor,
+        ):
+            links.append(
+                {
+                    "href": datasette.urls.table(database, query_name) + "/-/edit",
+                    "label": "Edit this query",
+                    "description": (
+                        "Change the title, description, SQL or visibility."
+                    ),
+                }
+            )
+        if await datasette.allowed(
+            action="delete-query",
+            resource=QueryResource(database, query_name),
+            actor=actor,
+        ):
+            links.append(
+                {
+                    "href": datasette.urls.table(database, query_name) + "/-/delete",
+                    "label": "Delete this query",
+                    "description": "Permanently remove this saved query.",
+                }
+            )
+        return links
+
+    return inner

datasette/default_table_actions.py

@@ -0,0 +1,29 @@
+from datasette import hookimpl
+from datasette.resources import TableResource
+
+
+@hookimpl
+def table_actions(datasette, actor, database, table, request):
+    async def inner():
+        db = datasette.get_database(database)
+        if not db.is_mutable:
+            return []
+        if not await datasette.allowed(
+            action="alter-table",
+            resource=TableResource(database=database, table=table),
+            actor=actor,
+        ):
+            return []
+        return [
+            {
+                "type": "button",
+                "label": "Alter table",
+                "description": "Change columns and primary key for this table.",
+                "attrs": {
+                    "aria-label": f"Alter table {table}",
+                    "data-table-action": "alter-table",
+                },
+            }
+        ]
+
+    return inner

datasette/events.py

@@ -1,8 +1,9 @@
 from abc import ABC, abstractproperty
 from dataclasses import asdict, dataclass, field
-from datasette.hookspecs import hookimpl
 from datetime import datetime, timezone
 
+from datasette.hookspecs import hookimpl
+
 
 @dataclass
 class Event(ABC):

datasette/extras.py

@@ -0,0 +1,141 @@
+import re
+from dataclasses import dataclass
+from enum import Enum
+from typing import ClassVar
+
+from asyncinject import Registry
+
+from datasette.utils.asgi import BadRequest
+
+
+def extra_names_from_request(request):
+    extra_bits = request.args.getlist("_extra")
+    extras = set()
+    for bit in extra_bits:
+        extras.update(part for part in bit.split(",") if part)
+    return extras
+
+
+class ExtraScope(Enum):
+    TABLE = "table"
+    ROW = "row"
+    QUERY = "query"
+
+
+@dataclass(frozen=True)
+class ExtraExample:
+    path: str | None = None
+    key: str | None = None
+    value: object | None = None
+    note: str | None = None
+
+
+class Provider:
+    name: ClassVar[str | None] = None
+    scopes: ClassVar[set[ExtraScope]] = set()
+    public: ClassVar[bool] = False
+
+    @classmethod
+    def key(cls):
+        return cls.name or _camel_to_snake(cls.__name__)
+
+    @classmethod
+    def available_for(cls, scope):
+        return scope in cls.scopes
+
+    async def resolve(self, context):
+        raise NotImplementedError
+
+
+class Extra(Provider):
+    description: ClassVar[str | None] = None
+    example: ClassVar[ExtraExample | None] = None
+    examples: ClassVar[dict[ExtraScope, ExtraExample | list[ExtraExample]]] = {}
+    public: ClassVar[bool] = True
+    expensive: ClassVar[bool] = False
+    docs_note: ClassVar[str | None] = None
+
+    @classmethod
+    def example_for_scope(cls, scope):
+        return cls.examples.get(scope, cls.example)
+
+
+class ExtraRegistry:
+    def __init__(self, classes):
+        self.classes = list(classes)
+        self.classes_by_name = {cls.key(): cls for cls in self.classes}
+        # Lazily-built shared state, keyed by scope. Safe to share across
+        # requests because Extra instances are stateless and asyncinject's
+        # Registry keeps per-call state local to each resolve_multi() call.
+        # If extras classes ever become registerable at runtime (e.g. via a
+        # plugin hook) these caches will need invalidating.
+        self._scope_registries = {}
+        self._allowed_names = {}
+
+    def classes_for_scope(self, scope, include_internal=True):
+        classes = [
+            cls
+            for cls in self.classes
+            if cls.available_for(scope) and (include_internal or cls.public)
+        ]
+        return classes
+
+    def public_classes_for_scope(self, scope):
+        return self.classes_for_scope(scope, include_internal=False)
+
+    def internal_classes_for_scope(self, scope):
+        # Extras that are available to HTML templates but excluded from
+        # JSON responses - plain Providers are dependency plumbing and
+        # never surface as keys, so they are not included
+        return [
+            cls
+            for cls in self.classes_for_scope(scope)
+            if issubclass(cls, Extra) and not cls.public
+        ]
+
+    def _registry_for_scope(self, scope):
+        registry = self._scope_registries.get(scope)
+        if registry is None:
+            registry = Registry()
+            for cls in self.classes_for_scope(scope):
+                registry.register(cls().resolve, name=cls.key())
+            self._scope_registries[scope] = registry
+        return registry
+
+    def _allowed_names_for_scope(self, scope, include_internal):
+        key = (scope, include_internal)
+        names = self._allowed_names.get(key)
+        if names is None:
+            names = {
+                cls.key()
+                for cls in self.classes_for_scope(
+                    scope, include_internal=include_internal
+                )
+            }
+            self._allowed_names[key] = names
+        return names
+
+    def validate_requested(self, requested, scope):
+        """
+        Raise BadRequest if any requested extra name is not a public extra
+        for this scope. Used by data formats such as .json - HTML pages
+        silently ignore unknown names instead.
+        """
+        allowed = self._allowed_names_for_scope(scope, include_internal=False)
+        unknown = sorted(name for name in requested if name not in allowed)
+        if unknown:
+            raise BadRequest("Unknown _extra: {}".format(", ".join(unknown)))
+
+    async def resolve(self, requested, context, scope, include_internal=False):
+        allowed_names = self._allowed_names_for_scope(scope, include_internal)
+        requested_names = [name for name in requested if name in allowed_names]
+        resolved = await self._registry_for_scope(scope).resolve_multi(
+            requested_names, results={"context": context}
+        )
+        return {name: resolved[name] for name in requested_names}
+
+
+def _camel_to_snake(name):
+    name = re.sub(r"(Extra|Provider)$", "", name)
+    name = re.sub("(.)([A-Z][a-z]+)", r"\1_\2", name)
+    return re.sub("([a-z0-9])([A-Z])", r"\1_\2", name).lower()

datasette/facets.py

@@ -1,12 +1,13 @@
 import json
 import urllib
+
 from datasette import hookimpl
 from datasette.database import QueryInterrupted
 from datasette.utils import (
+    detect_json1,
     escape_sqlite,
     path_with_added_args,
     path_with_removed_args,
-    detect_json1,
     sqlite3,
 )
 
@@ -30,7 +31,7 @@ def load_facet_configs(request, table_config):
             assert (
                 len(facet_config.values()) == 1
             ), "Metadata config dicts should be {type: config}"
-            type, facet_config = list(facet_config.items())[0]
+            type, facet_config = next(iter(facet_config.items()))
             if isinstance(facet_config, str):
                 facet_config = {"simple": facet_config}
         facet_configs.setdefault(type, []).append(
@@ -85,7 +86,7 @@ class Facet:
         self.database = database
         # For foreign key expansion. Can be None for e.g. stored SQL queries:
         self.table = table
-        self.sql = sql or f"select * from [{table}]"
+        self.sql = sql or f"select * from {escape_sqlite(table)}"
         self.params = params or []
         self.table_config = table_config
         # row_count can be None, in which case we calculate it ourselves:
@@ -160,18 +161,13 @@ class ColumnFacet(Facet):
         for column in columns:
             if column in already_enabled:
                 continue
-            suggested_facet_sql = """
-                with limited as (select * from ({sql}) limit {suggest_consider})
-                select {column} as value, count(*) as n from limited
+            suggested_facet_sql = f"""
+                with limited as (select * from ({self.sql}) limit {self.suggest_consider})
+                select {escape_sqlite(column)} as value, count(*) as n from limited
                 where value is not null
                 group by value
-                limit {limit}
-            """.format(
-                column=escape_sqlite(column),
-                sql=self.sql,
-                limit=facet_size + 1,
-                suggest_consider=self.suggest_consider,
-            )
+                limit {facet_size + 1}
+            """
             distinct_values = None
             try:
                 distinct_values = await self.ds.execute(
@@ -267,7 +263,7 @@ class ColumnFacet(Facet):
                 for row in facet_rows:
                     column_qs = column
                     if column.startswith("_"):
-                        column_qs = "{}__exact".format(column)
+                        column_qs = f"{column}__exact"
                     selected = (column_qs, str(row["value"])) in qs_pairs
                     if selected:
                         toggle_path = path_with_removed_args(
@@ -342,12 +338,12 @@ class ArrayFacet(Facet):
                         for v in await self.ds.execute(
                             self.database,
                             (
-                                "select {column} from ({sql}) "
-                                "where {column} is not null "
-                                "and {column} != '' "
-                                "and json_array_length({column}) > 0 "
+                                f"select {escape_sqlite(column)} from ({self.sql}) "
+                                f"where {escape_sqlite(column)} is not null "
+                                f"and {escape_sqlite(column)} != '' "
+                                f"and json_array_length({escape_sqlite(column)}) > 0 "
                                 "limit 100"
-                            ).format(column=escape_sqlite(column), sql=self.sql),
+                            ),
                             self.params,
                             truncate=False,
                             custom_time_limit=self.ds.setting(
@@ -388,14 +384,14 @@ class ArrayFacet(Facet):
             source = source_and_config["source"]
             column = config.get("column") or config["simple"]
             # https://github.com/simonw/datasette/issues/448
-            facet_sql = """
-                with inner as ({sql}),
+            facet_sql = f"""
+                with inner as ({self.sql}),
                 deduped_array_items as (
                     select
                         distinct j.value,
                         inner.*
                     from
-                        json_each([inner].{col}) j
+                        json_each([inner].{escape_sqlite(column)}) j
                         join inner
                 )
                 select
@@ -406,12 +402,8 @@ class ArrayFacet(Facet):
                 group by
                     value
                 order by
-                    count(*) desc, value limit {limit}
-            """.format(
-                col=escape_sqlite(column),
-                sql=self.sql,
-                limit=facet_size + 1,
-            )
+                    count(*) desc, value limit {facet_size + 1}
+            """
             try:
                 facet_rows_results = await self.ds.execute(
                     self.database,

datasette/filters.py

@@ -1,8 +1,11 @@
+import json
+from typing import ClassVar
+
 from datasette import hookimpl
 from datasette.resources import DatabaseResource
-from datasette.views.base import DatasetteError
 from datasette.utils.asgi import BadRequest
-import json
+from datasette.views.base import DatasetteError
+
 from .utils import detect_json1, escape_sqlite, path_with_removed_args
 
 
@@ -99,9 +102,9 @@ def search_filters(request, database, table, datasette):
                             fts_table=escape_sqlite(fts_table),
                             search_col=escape_sqlite(search_col),
                             match_clause=(
-                                ":search_{}".format(i)
+                                f":search_{i}"
                                 if search_mode_raw
-                                else "escape_fts(:search_{})".format(i)
+                                else f"escape_fts(:search_{i})"
                             ),
                         )
                     )
@@ -134,11 +137,11 @@ def through_filters(request, database, table, datasette):
                 value = through_data["value"]
                 db = datasette.get_database(database)
                 outgoing_foreign_keys = await db.foreign_keys_for_table(through_table)
-                try:
-                    fk_to_us = [
-                        fk for fk in outgoing_foreign_keys if fk["other_table"] == table
-                    ][0]
-                except IndexError:
+                fk_to_us = next(
+                    (fk for fk in outgoing_foreign_keys if fk["other_table"] == table),
+                    None,
+                )
+                if fk_to_us is None:
                     raise DatasetteError(
                         "Invalid _through - could not find corresponding foreign key"
                     )
@@ -365,7 +368,7 @@ class Filters:
             ),
         ]
     )
-    _filters_by_key = {f.key: f for f in _filters}
+    _filters_by_key: ClassVar[dict[str, Filter]] = {f.key: f for f in _filters}
 
     def __init__(self, pairs):
         self.pairs = pairs

datasette/fixtures.py

@@ -1,9 +1,10 @@
-from datasette.utils.sqlite import sqlite3
-from datasette.utils import documented
 import itertools
 import random
 import string
 
+from datasette.utils import documented
+from datasette.utils.sqlite import sqlite3
+
 __all__ = [
     "EXTRA_DATABASE_SQL",
     "TABLES",
@@ -346,9 +347,7 @@ CREATE VIEW searchable_view_configured_by_metadata AS
     + '\nINSERT INTO no_primary_key VALUES ("RENDER_CELL_DEMO", "a202", "b202", "c202");\n'
     + "\n".join(
         [
-            'INSERT INTO compound_three_primary_keys VALUES ("{a}", "{b}", "{c}", "{content}");'.format(
-                a=a, b=b, c=c, content=content
-            )
+            f'INSERT INTO compound_three_primary_keys VALUES ("{a}", "{b}", "{c}", "{content}");'
             for a, b, c, content in generate_compound_rows(1001)
         ]
     )

datasette/forbidden.py

@@ -1,9 +1,20 @@
-from datasette import hookimpl, Response
+from datasette import Response, hookimpl
+
+from .utils import add_cors_headers
 
 
 @hookimpl(trylast=True)
 def forbidden(datasette, request, message):
     async def inner():
+        if (
+            request.path.split("?")[0].endswith(".json")
+            or "application/json" in (request.headers.get("accept") or "")
+            or request.headers.get("content-type") == "application/json"
+        ):
+            headers = {}
+            if datasette.cors:
+                add_cors_headers(headers)
+            return Response.error(message, 403, headers=headers)
         return Response.html(
             await datasette.render_template(
                 "error.html",

datasette/handle_exception.py

@@ -1,16 +1,21 @@
-from datasette import hookimpl, Response
-from .utils import add_cors_headers
+import traceback
+
+from markupsafe import Markup
+
+from datasette import Response, hookimpl
+
+from .utils import add_cors_headers, error_body
 from .utils.asgi import (
     Base400,
 )
 from .views.base import DatasetteError
-from markupsafe import Markup
-import traceback
 
+# Debugger imports are deliberate - they back the "pdb" setting, which drops
+# into a debugger on unhandled exceptions
 try:
-    import ipdb as pdb
+    import ipdb as pdb  # noqa: T100
 except ImportError:
-    import pdb
+    import pdb  # noqa: T100
 
 try:
     import rich
@@ -28,6 +33,7 @@ def handle_exception(datasette, request, exception):
             rich.get_console().print_exception(show_locals=True)
 
         title = None
+        plain_message = None
         if isinstance(exception, Base400):
             status = exception.status
             info = {}
@@ -36,6 +42,7 @@ def handle_exception(datasette, request, exception):
             status = exception.status
             info = exception.error_dict
             message = exception.message
+            plain_message = exception.plain_message
             if exception.message_is_html:
                 message = Markup(message)
             title = exception.title
@@ -45,6 +52,13 @@ def handle_exception(datasette, request, exception):
             message = str(exception)
             traceback.print_exc()
         templates = [f"{status}.html", "error.html"]
+        headers = {}
+        if datasette.cors:
+            add_cors_headers(headers)
+        if request.path.split("?")[0].endswith(".json"):
+            body = dict(info)
+            body.update(error_body(plain_message or message, status))
+            return Response.json(body, status=status, headers=headers)
         info.update(
             {
                 "ok": False,
@@ -53,25 +67,18 @@ def handle_exception(datasette, request, exception):
                 "title": title,
             }
         )
-        headers = {}
-        if datasette.cors:
-            add_cors_headers(headers)
-        if request.path.split("?")[0].endswith(".json"):
-            return Response.json(info, status=status, headers=headers)
-        else:
-            environment = datasette.get_jinja_environment(request)
-            template = environment.select_template(templates)
-            return Response.html(
-                await template.render_async(
-                    dict(
-                        info,
-                        urls=datasette.urls,
-                        app_css_hash=datasette.app_css_hash(),
-                        menu_links=lambda: [],
-                    )
-                ),
-                status=status,
-                headers=headers,
-            )
+        environment = datasette.get_jinja_environment(request)
+        template = environment.select_template(templates)
+        return Response.html(
+            await template.render_async(
+                dict(
+                    info,
+                    urls=datasette.urls,
+                    menu_links=list,
+                )
+            ),
+            status=status,
+            headers=headers,
+        )
 
     return inner

datasette/hookspecs.py

@@ -1,5 +1,4 @@
-from pluggy import HookimplMarker
-from pluggy import HookspecMarker
+from pluggy import HookimplMarker, HookspecMarker
 
 hookspec = HookspecMarker("datasette")
 hookimpl = HookimplMarker("datasette")
@@ -159,32 +158,32 @@ def jump_items_sql(datasette, actor, request):
 
 @hookspec
 def row_actions(datasette, actor, request, database, table, row):
-    """Links for the row actions menu"""
+    """Items for the row actions menu"""
 
 
 @hookspec
 def table_actions(datasette, actor, database, table, request):
-    """Links for the table actions menu"""
+    """Items for the table actions menu"""
 
 
 @hookspec
 def view_actions(datasette, actor, database, view, request):
-    """Links for the view actions menu"""
+    """Items for the view actions menu"""
 
 
 @hookspec
 def query_actions(datasette, actor, database, query_name, request, sql, params):
-    """Links for the query and stored query actions menu"""
+    """Items for the query and stored query actions menu"""
 
 
 @hookspec
 def database_actions(datasette, actor, database, request):
-    """Links for the database actions menu"""
+    """Items for the database actions menu"""
 
 
 @hookspec
 def homepage_actions(datasette, actor, request):
-    """Links for the homepage actions menu"""
+    """Items for the homepage actions menu"""
 
 
 @hookspec

datasette/inspect.py

@@ -1,13 +1,13 @@
 import hashlib
 
 from .utils import (
-    detect_spatialite,
     detect_fts,
     detect_primary_keys,
+    detect_spatialite,
     escape_sqlite,
     get_all_foreign_keys,
-    table_columns,
     sqlite3,
+    table_columns,
 )
 
 HASH_BLOCK_SIZE = 1024 * 1024
@@ -95,10 +95,10 @@ def inspect_tables(conn, database_metadata):
                 """)
         ]
 
-    for t in tables.keys():
+    for t, table_info in tables.items():
         for hidden_table in hidden_tables:
             if t == hidden_table or t.startswith(hidden_table):
-                tables[t]["hidden"] = True
+                table_info["hidden"] = True
                 continue
 
     return tables

datasette/jump.py

@@ -21,7 +21,7 @@ class JumpSQL:
         search_text: str | None = None,
         display_name: str | None = None,
         item_type: str = "menu",
-    ) -> "JumpSQL":
+    ) -> JumpSQL:
         if search_text is None:
             search_text = " ".join(
                 text for text in (label, display_name, description) if text is not None

datasette/permissions.py

@@ -1,13 +1,21 @@
+import contextvars
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from typing import Any, NamedTuple
-import contextvars
 
 # Context variable to track when permission checks should be skipped
 _skip_permission_checks = contextvars.ContextVar(
     "skip_permission_checks", default=False
 )
 
+# Request-scoped cache of permission check results. The ASGI router sets
+# this to a fresh dict at the start of each request, so cached verdicts
+# never outlive a request or leak between actors. Keys are
+# (actor_json, action, parent, child) tuples, values are booleans.
+_permission_check_cache: contextvars.ContextVar[dict | None] = contextvars.ContextVar(
+    "permission_check_cache", default=None
+)
+
 
 class SkipPermissions:
     """Context manager to temporarily skip permission checks.
@@ -64,8 +72,8 @@ class Resource(ABC):
         )
 
     def __repr__(self) -> str:
-        return "{}(parent={!r}, child={!r})".format(
-            self.__class__.__name__, self.parent, self.child
+        return (
+            f"{self.__class__.__name__}(parent={self.parent!r}, child={self.child!r})"
         )
 
     @property
@@ -121,7 +129,6 @@ class Resource(ABC):
 
         Must return two columns: parent, child
         """
-        pass
 
 
 class AllowedResource(NamedTuple):

datasette/plugins.py

@@ -1,20 +1,14 @@
 import importlib
+import importlib.metadata as importlib_metadata
+import importlib.resources as importlib_resources
 import os
-import pluggy
-from pprint import pprint
 import sys
+from pprint import pprint
+
+import pluggy
+
 from . import hookspecs
 
-if sys.version_info >= (3, 9):
-    import importlib.resources as importlib_resources
-else:
-    import importlib_resources
-if sys.version_info >= (3, 10):
-    import importlib.metadata as importlib_metadata
-else:
-    import importlib_metadata
-
-
 DEFAULT_PLUGINS = (
     "datasette.publish.heroku",
     "datasette.publish.cloudrun",
@@ -31,6 +25,8 @@ DEFAULT_PLUGINS = (
     "datasette.default_debug_menu",
     "datasette.default_jump_items",
     "datasette.default_database_actions",
+    "datasette.default_table_actions",
+    "datasette.default_query_actions",
     "datasette.handle_exception",
     "datasette.forbidden",
     "datasette.events",
@@ -83,7 +79,7 @@ if DATASETTE_LOAD_PLUGINS is not None:
                     # Ensure name can be found in plugin_to_distinfo later:
                     pm._plugin_distinfo.append((mod, distribution))
         except importlib_metadata.PackageNotFoundError:
-            sys.stderr.write("Plugin {} could not be found\n".format(package_name))
+            sys.stderr.write(f"Plugin {package_name} could not be found\n")
 
 
 # Load default plugins

datasette/publish/cloudrun.py

@@ -1,15 +1,17 @@
-from datasette import hookimpl
-import click
 import json
 import os
 import re
 from subprocess import CalledProcessError, check_call, check_output
 
+import click
+
+from datasette import hookimpl
+
+from ..utils import temporary_docker_directory
 from .common import (
     add_common_publish_arguments_and_options,
     fail_if_publish_binary_not_installed,
 )
-from ..utils import temporary_docker_directory
 
 
 @hookimpl
@@ -219,7 +221,7 @@ def publish_subcommand(publish):
 
             check_call(
                 "gcloud builds submit --tag {}{}".format(
-                    image_id, " --timeout {}".format(timeout) if timeout else ""
+                    image_id, f" --timeout {timeout}" if timeout else ""
                 ),
                 shell=True,
             )
@@ -231,7 +233,7 @@ def publish_subcommand(publish):
             ("--min-instances", min_instances),
         ):
             if value is not None:
-                extra_deploy_options.append("{} {}".format(option, value))
+                extra_deploy_options.append(f"{option} {value}")
         check_call(
             "gcloud run deploy --allow-unauthenticated --platform=managed --image {} {}{}".format(
                 image_id,
@@ -258,24 +260,16 @@ def _ensure_artifact_registry(artifact_project, artifact_region, artifact_reposi
         ) from exc
 
     describe_cmd = (
-        "gcloud artifacts repositories describe {repo} --project {project} "
-        "--location {location} --quiet"
-    ).format(
-        repo=artifact_repository,
-        project=artifact_project,
-        location=artifact_region,
+        f"gcloud artifacts repositories describe {artifact_repository} --project {artifact_project} "
+        f"--location {artifact_region} --quiet"
     )
     try:
         check_call(describe_cmd, shell=True)
         return
     except CalledProcessError:
         create_cmd = (
-            "gcloud artifacts repositories create {repo} --repository-format=docker "
-            '--location {location} --project {project} --description "Datasette Cloud Run images" --quiet'
-        ).format(
-            repo=artifact_repository,
-            location=artifact_region,
-            project=artifact_project,
+            f"gcloud artifacts repositories create {artifact_repository} --repository-format=docker "
+            f'--location {artifact_region} --project {artifact_project} --description "Datasette Cloud Run images" --quiet'
         )
         try:
             check_call(create_cmd, shell=True)

datasette/publish/common.py

@@ -1,9 +1,11 @@
-from ..utils import StaticMount
-import click
 import os
 import shutil
 import sys
 
+import click
+
+from ..utils import StaticMount
+
 
 def add_common_publish_arguments_and_options(subcommand):
     for decorator in reversed(
@@ -76,9 +78,7 @@ def fail_if_publish_binary_not_installed(binary, publish_target, install_link):
     """Exit (with error message) if ``binary` isn't installed"""
     if not shutil.which(binary):
         click.secho(
-            "Publishing to {publish_target} requires {binary} to be installed and configured".format(
-                publish_target=publish_target, binary=binary
-            ),
+            f"Publishing to {publish_target} requires {binary} to be installed and configured",
             bg="red",
             fg="white",
             bold=True,

datasette/publish/heroku.py

@@ -1,19 +1,21 @@
-from contextlib import contextmanager
-from datasette import hookimpl
-import click
 import json
 import os
 import pathlib
 import shlex
 import shutil
-from subprocess import call, check_output
 import tempfile
+from contextlib import contextmanager
+from subprocess import call, check_output
+
+import click
+
+from datasette import hookimpl
+from datasette.utils import link_or_copy, link_or_copy_directory, parse_metadata
 
 from .common import (
     add_common_publish_arguments_and_options,
     fail_if_publish_binary_not_installed,
 )
-from datasette.utils import link_or_copy, link_or_copy_directory, parse_metadata
 
 
 @hookimpl
@@ -234,7 +236,7 @@ def temporary_heroku_directory(
             extras.extend(["--static", f"{mount_point}:{mount_point}"])
 
         quoted_files = " ".join(
-            ["-i {}".format(shlex.quote(file_name)) for file_name in file_names]
+            [f"-i {shlex.quote(file_name)}" for file_name in file_names]
         )
         procfile_cmd = "web: datasette serve --host 0.0.0.0 {quoted_files} --cors --port $PORT --inspect-file inspect-data.json {extras}".format(
             quoted_files=quoted_files, extras=" ".join(extras)

datasette/renderer.py

@@ -1,10 +1,13 @@
 import json
+
+from datasette.extras import extra_names_from_request
 from datasette.utils import (
-    value_as_boolean,
-    remove_infinites,
     CustomJSONEncoder,
+    error_body,
     path_from_row_pks,
+    remove_infinites,
     sqlite3,
+    value_as_boolean,
 )
 from datasette.utils.asgi import Response
 
@@ -51,8 +54,7 @@ def json_renderer(request, args, data, error, truncated=None):
     if error:
         shape = "objects"
         status_code = 400
-        data["error"] = error
-        data["ok"] = False
+        data.update(error_body(error, status_code))
 
     if truncated is not None:
         data["truncated"] = truncated
@@ -86,7 +88,8 @@ def json_renderer(request, args, data, error, truncated=None):
                         object_rows[pk_string] = row
                     data = object_rows
             if shape_error:
-                data = {"ok": False, "error": shape_error}
+                status_code = 400
+                data = error_body(shape_error, status_code)
         elif shape == "array":
             data = data["rows"]
 
@@ -99,16 +102,11 @@ def json_renderer(request, args, data, error, truncated=None):
             data["rows"] = [list(row.values()) for row in data["rows"]]
     else:
         status_code = 400
-        data = {
-            "ok": False,
-            "error": f"Invalid _shape: {shape}",
-            "status": 400,
-            "title": None,
-        }
+        data = error_body(f"Invalid _shape: {shape}", status_code)
 
     # Don't include "columns" in output
     # https://github.com/simonw/datasette/issues/2136
-    if isinstance(data, dict) and "columns" not in request.args.getlist("_extra"):
+    if isinstance(data, dict) and "columns" not in extra_names_from_request(request):
         data.pop("columns", None)
 
     # Handle _nl option for _shape=array

datasette/static/autocomplete.js

@@ -0,0 +1,344 @@
+(function () {
+  function autocompleteValueFromRow(row) {
+    var pks = (row && row.pks) || {};
+    var keys = Object.keys(pks);
+    if (!keys.length) {
+      return "";
+    }
+    if (keys.length === 1) {
+      return String(pks[keys[0]]);
+    }
+    return keys
+      .map(function (key) {
+        return key + "=" + pks[key];
+      })
+      .join(", ");
+  }
+
+  function autocompleteLabelFromRow(row) {
+    var value = autocompleteValueFromRow(row);
+    if (row.label && String(row.label) !== value) {
+      return row.label + " (" + value + ")";
+    }
+    return value;
+  }
+
+  if (!window.customElements || customElements.get("datasette-autocomplete")) {
+    return;
+  }
+
+  class DatasetteAutocomplete extends HTMLElement {
+    constructor() {
+      super();
+      this.input = null;
+      this.listbox = null;
+      this.status = null;
+      this.results = [];
+      this.activeIndex = -1;
+      this.fetchId = 0;
+      this.searchTimer = null;
+      this.boundInput = this.handleInput.bind(this);
+      this.boundKeydown = this.handleKeydown.bind(this);
+      this.boundBlur = this.handleBlur.bind(this);
+      this.boundFocus = this.handleFocus.bind(this);
+      this.boundPositionListbox = this.positionListbox.bind(this);
+    }
+
+    connectedCallback() {
+      if (this.input) {
+        return;
+      }
+      this.input = this.querySelector("input");
+      if (!this.input) {
+        return;
+      }
+
+      var inputId =
+        this.input.id ||
+        "datasette-autocomplete-" + Math.random().toString(36).slice(2);
+      this.input.id = inputId;
+      var listboxId = inputId + "-listbox";
+      var statusId = inputId + "-status";
+
+      this.classList.add("datasette-autocomplete");
+      this.input.setAttribute("role", "combobox");
+      this.input.setAttribute("aria-autocomplete", "list");
+      this.input.setAttribute("aria-expanded", "false");
+      this.input.setAttribute("aria-controls", listboxId);
+      this.input.setAttribute("autocomplete", "off");
+
+      this.listbox = document.createElement("div");
+      this.listbox.className = "datasette-autocomplete-list";
+      this.listbox.id = listboxId;
+      this.listbox.setAttribute("role", "listbox");
+      this.listbox.hidden = true;
+
+      this.status = document.createElement("span");
+      this.status.className = "datasette-autocomplete-status";
+      this.status.id = statusId;
+      this.status.setAttribute("role", "status");
+      this.status.setAttribute("aria-live", "polite");
+
+      this.input.setAttribute(
+        "aria-describedby",
+        [this.input.getAttribute("aria-describedby"), statusId]
+          .filter(Boolean)
+          .join(" "),
+      );
+
+      this.appendChild(this.listbox);
+      this.appendChild(this.status);
+
+      this.input.addEventListener("input", this.boundInput);
+      this.input.addEventListener("keydown", this.boundKeydown);
+      this.input.addEventListener("blur", this.boundBlur);
+      this.input.addEventListener("focus", this.boundFocus);
+    }
+
+    disconnectedCallback() {
+      if (!this.input) {
+        return;
+      }
+      this.input.removeEventListener("input", this.boundInput);
+      this.input.removeEventListener("keydown", this.boundKeydown);
+      this.input.removeEventListener("blur", this.boundBlur);
+      this.input.removeEventListener("focus", this.boundFocus);
+    }
+
+    handleInput() {
+      this.scheduleSearch();
+    }
+
+    handleFocus() {
+      if (this.input.value.trim() || this.hasAttribute("suggest-on-focus")) {
+        this.scheduleSearch();
+      }
+    }
+
+    handleBlur() {
+      window.setTimeout(() => this.close(), 150);
+    }
+
+    handleKeydown(ev) {
+      if (ev.key === "Escape") {
+        if (!this.listbox.hidden) {
+          ev.preventDefault();
+          this.close();
+        }
+        return;
+      }
+      if (ev.key === "ArrowDown") {
+        ev.preventDefault();
+        if (this.listbox.hidden) {
+          this.scheduleSearch();
+        } else {
+          this.setActiveIndex(this.activeIndex + 1);
+        }
+        return;
+      }
+      if (ev.key === "ArrowUp") {
+        ev.preventDefault();
+        if (!this.listbox.hidden) {
+          this.setActiveIndex(this.activeIndex - 1);
+        }
+        return;
+      }
+      if (ev.key === "Enter" && !this.listbox.hidden && this.activeIndex >= 0) {
+        ev.preventDefault();
+        this.chooseIndex(this.activeIndex);
+      }
+    }
+
+    scheduleSearch() {
+      window.clearTimeout(this.searchTimer);
+      this.searchTimer = window.setTimeout(() => this.search(), 150);
+    }
+
+    async search() {
+      var query = this.input.value.trim();
+      var initial = !query && this.hasAttribute("suggest-on-focus");
+      if (!query && !initial) {
+        this.close();
+        this.status.textContent = "";
+        return;
+      }
+      var src = this.getAttribute("src");
+      if (!src) {
+        return;
+      }
+
+      var url = new URL(src, location.href);
+      url.searchParams.set("q", query);
+      if (initial) {
+        url.searchParams.set("_initial", "1");
+      } else {
+        url.searchParams.delete("_initial");
+      }
+      var fetchId = this.fetchId + 1;
+      this.fetchId = fetchId;
+      this.status.textContent = "Searching...";
+
+      try {
+        var response = await fetch(url.toString(), {
+          headers: {
+            Accept: "application/json",
+          },
+        });
+        if (!response.ok) {
+          throw new Error("HTTP " + response.status);
+        }
+        var data = await response.json();
+        if (fetchId !== this.fetchId) {
+          return;
+        }
+        this.results = (data && data.rows) || [];
+        this.render();
+      } catch (_error) {
+        if (fetchId !== this.fetchId) {
+          return;
+        }
+        this.results = [];
+        this.close();
+        this.status.textContent = "Could not load suggestions";
+      }
+    }
+
+    render() {
+      this.listbox.textContent = "";
+      this.activeIndex = -1;
+      if (!this.results.length) {
+        this.close();
+        this.status.textContent = "No matches";
+        return;
+      }
+
+      this.results.forEach((row, index) => {
+        var option = document.createElement("div");
+        option.className = "datasette-autocomplete-option";
+        option.id = this.input.id + "-option-" + index;
+        option.setAttribute("role", "option");
+        option.setAttribute("aria-selected", "false");
+        option.dataset.index = String(index);
+        option.dataset.value = autocompleteValueFromRow(row);
+        option.textContent = autocompleteLabelFromRow(row);
+        option.addEventListener("mousedown", (ev) => {
+          ev.preventDefault();
+          this.chooseIndex(index);
+        });
+        this.listbox.appendChild(option);
+      });
+
+      this.listbox.hidden = false;
+      this.input.setAttribute("aria-expanded", "true");
+      this.status.textContent =
+        this.results.length + (this.results.length === 1 ? " match" : " matches");
+      this.positionListbox();
+      this.setActiveIndex(0);
+    }
+
+    positionListbox() {
+      if (!this.input || !this.listbox || this.listbox.hidden) {
+        return;
+      }
+
+      var gap = 3;
+      var margin = 8;
+      var inputRect = this.input.getBoundingClientRect();
+      this.listbox.style.maxHeight = "";
+      var defaultMaxHeight = parseFloat(
+        window.getComputedStyle(this.listbox).maxHeight,
+      );
+      if (!Number.isFinite(defaultMaxHeight)) {
+        defaultMaxHeight = 256;
+      }
+      var scrollHeight = Math.ceil(this.listbox.scrollHeight);
+      var desiredHeight = Math.min(scrollHeight, defaultMaxHeight);
+      var availableBelow = Math.max(
+        0,
+        (window.innerHeight || document.documentElement.clientHeight) -
+          inputRect.bottom -
+          gap -
+          margin,
+      );
+
+      this.listbox.style.left = inputRect.left + "px";
+      this.listbox.style.top = inputRect.bottom + gap + "px";
+      this.listbox.style.width = inputRect.width + "px";
+      if (scrollHeight <= defaultMaxHeight && scrollHeight <= availableBelow) {
+        this.listbox.style.maxHeight = "none";
+      } else {
+        this.listbox.style.maxHeight =
+          Math.min(defaultMaxHeight, desiredHeight, availableBelow || defaultMaxHeight) +
+          "px";
+      }
+      window.addEventListener("resize", this.boundPositionListbox);
+      document.addEventListener("scroll", this.boundPositionListbox, true);
+    }
+
+    setActiveIndex(index) {
+      var options = this.listbox.querySelectorAll("[role='option']");
+      if (!options.length) {
+        this.activeIndex = -1;
+        this.input.removeAttribute("aria-activedescendant");
+        return;
+      }
+      if (index < 0) {
+        index = options.length - 1;
+      }
+      if (index >= options.length) {
+        index = 0;
+      }
+      options.forEach((option, optionIndex) => {
+        option.setAttribute(
+          "aria-selected",
+          optionIndex === index ? "true" : "false",
+        );
+      });
+      this.activeIndex = index;
+      this.input.setAttribute("aria-activedescendant", options[index].id);
+    }
+
+    chooseIndex(index) {
+      var row = this.results[index];
+      if (!row) {
+        return;
+      }
+      var value = autocompleteValueFromRow(row);
+      var label = autocompleteLabelFromRow(row);
+      this.input.value = value;
+      this.input.dispatchEvent(new Event("change", { bubbles: true }));
+      this.close();
+      this.status.textContent = "Selected " + label;
+      this.dispatchEvent(
+        new CustomEvent("datasette-autocomplete-select", {
+          bubbles: true,
+          detail: {
+            row: row,
+            value: value,
+            label: label,
+          },
+        }),
+      );
+    }
+
+    close() {
+      if (this.listbox) {
+        this.listbox.hidden = true;
+        this.listbox.textContent = "";
+        this.listbox.style.left = "";
+        this.listbox.style.maxHeight = "";
+        this.listbox.style.top = "";
+        this.listbox.style.width = "";
+      }
+      if (this.input) {
+        this.input.setAttribute("aria-expanded", "false");
+        this.input.removeAttribute("aria-activedescendant");
+      }
+      window.removeEventListener("resize", this.boundPositionListbox);
+      document.removeEventListener("scroll", this.boundPositionListbox, true);
+      this.activeIndex = -1;
+    }
+  }
+
+  customElements.define("datasette-autocomplete", DatasetteAutocomplete);
+})();

datasette/static/column-chooser.js

@@ -31,9 +31,9 @@ class ColumnChooser extends HTMLElement {
       <style>
         :host {
           --ink: #0f0f0f;
-          --paper: #f5f3ef;
+          --paper: #eef6ff;
           --muted: #6b6b6b;
-          --rule: #e2dfd8;
+          --rule: #d8e6f5;
           --accent: #1a56db;
           --accent-light: #e8effd;
           --card: #ffffff;

datasette/static/datasette-manager.js

@@ -82,6 +82,35 @@ const datasetteManager = {
     return columnActions;
   },
 
+  /**
+   * Allows JavaScript plugins to replace or enhance insert/edit modal fields
+   * for specific Datasette column types.
+   *
+   * The first plugin to return a control object wins. Returning null or
+   * undefined means "I do not handle this field".
+   */
+  makeColumnField: (context) => {
+    for (const [pluginName, plugin] of datasetteManager.plugins) {
+      if (!plugin.makeColumnField) {
+        continue;
+      }
+      let control = null;
+      try {
+        control = plugin.makeColumnField(context);
+      } catch (error) {
+        console.error(
+          `Error in makeColumnField() for plugin ${pluginName}`,
+          error,
+        );
+        continue;
+      }
+      if (control) {
+        return Object.assign({ pluginName }, control);
+      }
+    }
+    return null;
+  },
+
   makeJumpSections: (context) => {
     let jumpSections = [];
 

datasette/static/table.js

@@ -12,7 +12,6 @@ var DROPDOWN_ICON_SVG = `<svg xmlns="http://www.w3.org/2000/svg" width="14" heig
 
 var SET_COLUMN_TYPE_DIALOG_ID = "set-column-type-dialog";
 var setColumnTypeDialogState = null;
-
 function getParams() {
   return new URLSearchParams(location.search);
 }
@@ -634,32 +633,151 @@ const initDatasetteTable = function (manager) {
   });
 };
 
-/* Add x buttons to the filter rows */
-function addButtonsToFilterRows(manager) {
-  var x = "✖";
-  var rows = Array.from(
-    document.querySelectorAll(manager.selectors.filterRow),
+function filterRowSelector(manager) {
+  return manager.selectors.filterRows || manager.selectors.filterRow;
+}
+
+function filterRowsWithControls(manager) {
+  return Array.from(
+    document.querySelectorAll(filterRowSelector(manager)),
   ).filter((el) => el.querySelector(".filter-op"));
-  rows.forEach((row) => {
-    var a = document.createElement("a");
-    a.setAttribute("href", "#");
-    a.setAttribute("aria-label", "Remove this filter");
-    a.style.textDecoration = "none";
-    a.innerText = x;
-    a.addEventListener("click", (ev) => {
-      ev.preventDefault();
-      let row = ev.target.closest("div");
-      row.querySelector("select").value = "";
-      row.querySelector(".filter-op select").value = "exact";
-      row.querySelector("input.filter-value").value = "";
-      ev.target.closest("a").style.display = "none";
-    });
-    row.appendChild(a);
+}
+
+function filterRowNumberFromName(name) {
+  var match = name && name.match(/^_filter_column_(\d+)$/);
+  return match ? parseInt(match[1], 10) : 0;
+}
+
+function nextFilterRowNumber(manager) {
+  return filterRowsWithControls(manager).reduce((max, row) => {
     var column = row.querySelector("select");
-    if (!column.value) {
-      a.style.display = "none";
+    return Math.max(max, filterRowNumberFromName(column && column.name));
+  }, 0) + 1;
+}
+
+function setFilterRowNumber(row, number) {
+  row.querySelector("select").name = `_filter_column_${number}`;
+  row.querySelector(".filter-op select").name = `_filter_op_${number}`;
+  row.querySelector("input.filter-value").name = `_filter_value_${number}`;
+}
+
+function resetFilterRow(row) {
+  row.querySelector("select").value = "";
+  row.querySelector(".filter-op select").value = "exact";
+  row.querySelector("input.filter-value").value = "";
+}
+
+function updateFilterRowButtons(manager) {
+  var rows = filterRowsWithControls(manager);
+  rows.forEach((row, index) => {
+    var removeButton = row.querySelector(".filter-row-remove");
+    var addButton = row.querySelector(".filter-row-add");
+    var column = row.querySelector("select");
+    if (removeButton) {
+      removeButton.hidden = index === 0;
+    }
+    if (addButton) {
+      addButton.hidden = index !== rows.length - 1 || !column.value;
+    }
+    var visibleButtonCount = [removeButton, addButton].filter(function (button) {
+      return button && !button.hidden;
+    }).length;
+    row.classList.toggle(
+      "filter-controls-row-has-buttons",
+      visibleButtonCount > 0,
+    );
+    row.classList.toggle(
+      "filter-controls-row-one-button",
+      visibleButtonCount === 1,
+    );
+    row.classList.toggle(
+      "filter-controls-row-two-buttons",
+      visibleButtonCount === 2,
+    );
+  });
+}
+
+function cloneFilterRow(row) {
+  var clone = row.cloneNode(true);
+  clone.querySelector("select").name = "_filter_column";
+  clone.querySelector(".filter-op select").name = "_filter_op";
+  clone.querySelector("input.filter-value").name = "_filter_value";
+  resetFilterRow(clone);
+  clone.querySelectorAll(".filter-row-icon").forEach((button) => button.remove());
+  return clone;
+}
+
+var FILTER_REMOVE_ICON_SVG = `<svg class="filter-row-remove-icon" aria-hidden="true" xmlns="http://www.w3.org/2000/svg" width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.1" stroke-linecap="round" stroke-linejoin="round">
+  <path d="M3 6h18"></path>
+  <path d="M8 6V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2"></path>
+  <path d="M19 6l-1 14a2 2 0 0 1-2 2H8a2 2 0 0 1-2-2L5 6"></path>
+  <path d="M10 11v6"></path>
+  <path d="M14 11v6"></path>
+</svg>`;
+
+var FILTER_ADD_ICON_SVG = `<svg class="filter-row-add-icon" aria-hidden="true" xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="3" stroke-linecap="round" stroke-linejoin="round">
+  <path d="M5 12h14"></path>
+  <path d="M12 5v14"></path>
+</svg>`;
+
+function addFilterRowButtons(row, manager) {
+  var removeButton = document.createElement("button");
+  removeButton.type = "button";
+  removeButton.className = "filter-row-icon filter-row-remove";
+  removeButton.setAttribute("aria-label", "Remove this filter");
+  removeButton.title = "Remove this filter";
+  removeButton.tabIndex = 0;
+  removeButton.innerHTML = FILTER_REMOVE_ICON_SVG;
+  removeButton.addEventListener("click", (ev) => {
+    var row = ev.currentTarget.closest(filterRowSelector(manager));
+    var rows = filterRowsWithControls(manager);
+    var rowIndex = rows.indexOf(row);
+    var focusRow = rows[rowIndex + 1] || rows[rowIndex - 1] || null;
+    row.remove();
+    updateFilterRowButtons(manager);
+    if (focusRow) {
+      var focusTarget =
+        focusRow.querySelector(".filter-row-add:not([hidden])") ||
+        focusRow.querySelector("select");
+      if (focusTarget) {
+        focusTarget.focus();
+      }
     }
   });
+  row.appendChild(removeButton);
+
+  var addButton = document.createElement("button");
+  addButton.type = "button";
+  addButton.className = "filter-row-icon filter-row-add";
+  addButton.setAttribute("aria-label", "Add another filter");
+  addButton.title = "Add another filter";
+  addButton.tabIndex = 0;
+  addButton.innerHTML = FILTER_ADD_ICON_SVG;
+  addButton.addEventListener("click", (ev) => {
+    var row = ev.currentTarget.closest(filterRowSelector(manager));
+    if (row.querySelector("select").name === "_filter_column") {
+      setFilterRowNumber(row, nextFilterRowNumber(manager));
+    }
+    var clone = cloneFilterRow(row);
+    addFilterRowButtons(clone, manager);
+    row.parentNode.insertBefore(clone, row.nextSibling);
+    updateFilterRowButtons(manager);
+    clone.querySelector("select").focus();
+  });
+  row.appendChild(addButton);
+
+  row.querySelector("select").addEventListener("change", () => {
+    updateFilterRowButtons(manager);
+  });
+}
+
+/* Add buttons to the filter rows */
+function addButtonsToFilterRows(manager) {
+  var rows = filterRowsWithControls(manager);
+  rows.forEach((row) => {
+    addFilterRowButtons(row, manager);
+  });
+  updateFilterRowButtons(manager);
 }
 
 /* Set up datalist autocomplete for filter values */
@@ -688,11 +806,11 @@ function initAutocompleteForFilterValues(manager) {
     });
   }
   createDataLists();
-  // When any select with name=_filter_column changes, update the datalist
+  // When any filter column select changes, update the datalist
   document.body.addEventListener("change", function (event) {
-    if (event.target.name === "_filter_column") {
+    if (event.target.name && event.target.name.startsWith("_filter_column")) {
       event.target
-        .closest(manager.selectors.filterRow)
+        .closest(filterRowSelector(manager))
         .querySelector(".filter-value")
         .setAttribute("list", "datalist-" + event.target.value);
     }

datasette/stored_queries.py

@@ -1,8 +1,9 @@
 from __future__ import annotations
 
-from dataclasses import dataclass
 import json
-from typing import Any, Iterable
+from collections.abc import Iterable
+from dataclasses import dataclass
+from typing import Any
 
 from .utils import tilde_encode, urlsafe_components
 
@@ -62,7 +63,6 @@ def stored_query_to_dict(query: StoredQuery) -> dict[str, Any]:
         "description_html": query.description_html,
         "hide_sql": query.hide_sql,
         "fragment": query.fragment,
-        "params": list(query.parameters),
         "parameters": list(query.parameters),
         "is_write": query.is_write,
         "is_private": query.is_private,
@@ -84,7 +84,6 @@ def stored_query_page_to_dict(page: StoredQueryPage) -> dict[str, Any]:
     return {
         "queries": [stored_query_to_dict(query) for query in page.queries],
         "next": page.next,
-        "has_more": page.has_more,
         "limit": page.limit,
     }
 
@@ -388,7 +387,7 @@ async def count_queries(
                 OR q.sql LIKE :query_search
             )
             """)
-        params["query_search"] = "%{}%".format(q)
+        params["query_search"] = f"%{q}%"
     if is_write is not None:
         where_clauses.append("q.is_write = :query_is_write")
         params["query_is_write"] = int(bool(is_write))
@@ -464,7 +463,7 @@ async def list_queries(
         except ValueError:
             components = []
         if database is None and len(components) == 3:
-            where_clauses.append("""
+            where_clauses.append(f"""
                 (
                     q.database_name > :cursor_database
                     OR (
@@ -478,12 +477,12 @@ async def list_queries(
                         )
                     )
                 )
-                """.format(sort_key_sql=sort_key_sql))
+                """)
             params["cursor_database"] = components[0]
             params["cursor_sort_key"] = components[1]
             params["cursor_name"] = components[2]
         elif database is not None and len(components) == 2:
-            where_clauses.append("""
+            where_clauses.append(f"""
                 (
                     {sort_key_sql} > :cursor_sort_key
                     OR (
@@ -491,7 +490,7 @@ async def list_queries(
                         AND q.name > :cursor_name
                     )
                 )
-                """.format(sort_key_sql=sort_key_sql))
+                """)
             params["cursor_sort_key"] = components[0]
             params["cursor_name"] = components[1]
 
@@ -504,7 +503,7 @@ async def list_queries(
                 OR q.sql LIKE :query_search
             )
             """)
-        params["query_search"] = "%{}%".format(q)
+        params["query_search"] = f"%{q}%"
     if is_write is not None:
         where_clauses.append("q.is_write = :query_is_write")
         params["query_is_write"] = int(bool(is_write))

datasette/template_contexts.py

@@ -0,0 +1,40 @@
+"""
+Index of the documented template contexts for Datasette's core HTML pages.
+
+This module deliberately contains no documentation strings of its own -
+the documentation lives next to the code it describes:
+
+- Every page renders a Context dataclass defined in its view module
+  (DatabaseContext, QueryContext in views/database.py, TableContext in
+  views/table.py, RowContext in views/row.py). Fields added by view code
+  carry ``help`` metadata; fields declared with from_extra() take their
+  documentation from the description on the matching Extra class in
+  views/table_extras.py.
+- The keys render_template() adds to every page are documented in
+  TEMPLATE_BASE_CONTEXT in datasette/app.py, next to the code that adds
+  them.
+
+The contract tests in tests/test_template_context.py assert that the real
+rendered context for each page exactly matches what is documented, and
+docs/template_context_doc.py generates docs/template_context.rst from the
+same classes.
+"""
+
+from datasette.app import TEMPLATE_BASE_CONTEXT
+from datasette.views.database import DatabaseContext, QueryContext
+from datasette.views.row import RowContext
+from datasette.views.table import TableContext
+
+PAGES = {
+    "database": DatabaseContext,
+    "query": QueryContext,
+    "table": TableContext,
+    "row": RowContext,
+}
+
+
+def documented_context_keys(page_name):
+    "Set of every documented key for the named page, including base context keys"
+    return set(TEMPLATE_BASE_CONTEXT) | {
+        f.name for f in PAGES[page_name].documented_fields()
+    }

datasette/templates/_action_menu.html

@@ -15,14 +15,22 @@
         <div class="hook"></div>
         <ul role="menu">
             {% for link in action_links %}
-            <li role="none"><a href="{{ link.href }}" role="menuitem" tabindex="-1">{{ link.label }}
-            {% if link.description %}
-                <p class="dropdown-description">{{ link.description }}</p>
-            {% endif %}</a>
+            <li role="none">
+            {% if link.get("type") == "button" %}
+                <button type="button" class="button-as-link action-menu-button" role="menuitem" tabindex="-1"{% for name, value in (link.get("attrs") or {}).items() %} {{ name }}="{{ value }}"{% endfor %}>{{ link.label }}
+                {% if link.description %}
+                    <span class="dropdown-description">{{ link.description }}</span>
+                {% endif %}</button>
+            {% else %}
+                <a href="{{ link.href }}" role="menuitem" tabindex="-1">{{ link.label }}
+                {% if link.description %}
+                    <span class="dropdown-description">{{ link.description }}</span>
+                {% endif %}</a>
+            {% endif %}
             </li>
             {% endfor %}
         </ul>
     </div>
 </details>
 </div>
-{% endif %}
+{% endif %}

datasette/templates/_codemirror.html

@@ -1,5 +1,5 @@
-<script src="{{ base_url }}-/static/sql-formatter-2.3.3.min.js" defer></script>
-<script src="{{ base_url }}-/static/cm-editor-6.0.1.bundle.js"></script>
+<script src="{{ static('sql-formatter-2.3.3.min.js') }}" defer></script>
+<script src="{{ static('cm-editor-6.0.1.bundle.js') }}"></script>
 <style>
   .cm-editor {
     resize: both;

datasette/templates/_facet_results.html

@@ -12,9 +12,9 @@
             <ul class="tight-bullets">
                 {% for facet_value in facet_info.results %}
                     {% if not facet_value.selected %}
-                        <li><a href="{{ facet_value.toggle_url }}" data-facet-value="{{ facet_value.value }}">{{ (facet_value.label | string()) or "-" }}</a> {{ "{:,}".format(facet_value.count) }}</li>
+                        <li><a href="{{ facet_value.toggle_url }}" data-facet-value="{{ facet_value.value }}">{{ (facet_value.label | string()) or "-" }}</a> <span class="facet-count">{{ "{:,}".format(facet_value.count) }}</span></li>
                     {% else %}
-                        <li>{{ facet_value.label or "-" }} &middot; {{ "{:,}".format(facet_value.count) }} <a href="{{ facet_value.toggle_url }}" class="cross">&#x2716;</a></li>
+                        <li>{{ facet_value.label or "-" }} &middot; <span class="facet-count">{{ "{:,}".format(facet_value.count) }}</span> <a href="{{ facet_value.toggle_url }}" class="cross">&#x2716;</a></li>
                     {% endif %}
                 {% endfor %}
                 {% if facet_info.truncated %}

datasette/templates/_permission_ui_styles.html

@@ -6,8 +6,20 @@
     padding: 1.5em;
     margin-bottom: 2em;
 }
+.permission-form form {
+    max-width: 60rem;
+}
+.permission-form-grid {
+    display: grid;
+    gap: 1.5rem;
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+}
+.permission-form-result {
+    margin-top: 1rem;
+    max-width: 60rem;
+}
 .form-section {
-    margin-bottom: 1em;
+    margin-bottom: 1.25em;
 }
 .form-section label {
     display: block;
@@ -15,22 +27,51 @@
     font-weight: bold;
 }
 .form-section input[type="text"],
-.form-section select {
-    width: 100%;
-    max-width: 500px;
-    padding: 0.5em;
+.form-section input[type="number"],
+.form-section select,
+.permission-textarea {
+    background-color: #fff;
+    border: 1px solid #aaa;
+    border-radius: 4px;
     box-sizing: border-box;
-    border: 1px solid #ccc;
-    border-radius: 3px;
+    box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.08);
+    color: #222;
+    font-family: inherit;
+    font-size: 1rem;
+    line-height: 1.4;
+    max-width: none;
+    width: 100%;
+}
+.form-section input[type="text"] {
+    height: 3rem;
+    padding: 0.6rem 0.75rem;
+}
+.form-section input[type="number"] {
+    height: 3rem;
+    max-width: 7rem;
+    padding: 0.6rem 0.75rem;
+}
+.form-section select {
+    height: 3rem;
+    padding: 0.6rem 0.75rem;
+}
+.permission-textarea {
+    font-family: monospace;
+    min-height: 12rem;
+    padding: 0.75rem;
+    resize: vertical;
 }
 .form-section input[type="text"]:focus,
-.form-section select:focus {
-    outline: 2px solid #0066cc;
+.form-section input[type="number"]:focus,
+.form-section select:focus,
+.permission-textarea:focus {
     border-color: #0066cc;
+    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.18);
+    outline: none;
 }
 .form-section small {
     display: block;
-    margin-top: 0.3em;
+    margin-top: 0.45em;
     color: #666;
 }
 .form-actions {
@@ -142,4 +183,9 @@
     text-align: center;
     color: #666;
 }
+@media only screen and (max-width: 576px) {
+    .permission-form-grid {
+        grid-template-columns: minmax(0, 1fr);
+    }
+}
 </style>

datasette/templates/_permissions_debug_tabs.html

@@ -44,10 +44,10 @@
 </style>
 
 <nav class="permissions-debug-tabs">
-    <a href="{{ urls.path('-/permissions') }}" {% if current_tab == "permissions" %}class="active"{% endif %}>Playground</a>
-    <a href="{{ urls.path('-/check') }}{{ query_string }}" {% if current_tab == "check" %}class="active"{% endif %}>Check</a>
-    <a href="{{ urls.path('-/allowed') }}{{ query_string }}" {% if current_tab == "allowed" %}class="active"{% endif %}>Allowed</a>
-    <a href="{{ urls.path('-/rules') }}{{ query_string }}" {% if current_tab == "rules" %}class="active"{% endif %}>Rules</a>
+    <a href="{{ urls.path('-/check') }}{{ query_string }}" {% if current_tab == "check" %}class="active"{% endif %}>Explain</a>
+    <a href="{{ urls.path('-/allowed') }}{{ query_string }}" {% if current_tab == "allowed" %}class="active"{% endif %}>Access map</a>
+    <a href="{{ urls.path('-/rules') }}{{ query_string }}" {% if current_tab == "rules" %}class="active"{% endif %}>Rule explorer</a>
+    <a href="{{ urls.path('-/permissions') }}" {% if current_tab == "permissions" %}class="active"{% endif %}>Activity</a>
     <a href="{{ urls.path('-/actions') }}" {% if current_tab == "actions" %}class="active"{% endif %}>Actions</a>
     <a href="{{ urls.path('-/allow-debug') }}" {% if current_tab == "allow_debug" %}class="active"{% endif %}>Allow debug</a>
 </nav>

datasette/templates/_query_form_styles.html

@@ -0,0 +1,138 @@
+<style>
+.query-create-page {
+    max-width: 64rem;
+}
+.query-create-form {
+    --query-create-label-width: clamp(7rem, 18vw, 10rem);
+    --query-create-column-gap: 0.8rem;
+    --query-create-control-width: minmax(16rem, 1fr);
+}
+.query-create-fields {
+    margin: 0 0 0.85rem;
+    max-width: 52rem;
+}
+.query-create-field {
+    align-items: start;
+    column-gap: var(--query-create-column-gap);
+    display: grid;
+    grid-template-columns: var(--query-create-label-width) var(--query-create-control-width);
+    margin: 0 0 0.65rem;
+}
+.query-create-field label {
+    padding-top: 0.55rem;
+    width: auto;
+}
+.query-create-field input[type=text],
+.query-create-field textarea {
+    box-sizing: border-box;
+    width: 100%;
+}
+form.sql .query-create-field textarea {
+    width: 100%;
+}
+.query-create-url-control {
+    align-items: center;
+    box-sizing: border-box;
+    display: grid;
+    gap: 0.35rem;
+    grid-template-columns: max-content minmax(12rem, 1fr);
+    width: 100%;
+}
+.query-create-url-prefix {
+    color: #4f5b6d;
+    font-family: var(--font-monospace, monospace);
+    white-space: nowrap;
+}
+.query-create-url-control input[type=text] {
+    border: 1px solid #ccc;
+    border-radius: 3px;
+}
+.query-create-url-static {
+    color: #39445a;
+    font-family: var(--font-monospace, monospace);
+    word-break: break-all;
+}
+.query-create-field textarea {
+    border: 1px solid #ccc;
+    border-radius: 3px;
+    display: block;
+    font-family: Helvetica, sans-serif;
+    font-size: 1em;
+    min-height: 5rem;
+    padding: 9px 4px;
+    resize: vertical;
+}
+form.sql .query-create-sql {
+    column-gap: var(--query-create-column-gap);
+    display: grid;
+    grid-template-columns: var(--query-create-label-width) var(--query-create-control-width);
+    margin: 0.9rem 0 0.75rem;
+    max-width: 52rem;
+}
+.query-create-sql .cm-editor,
+form.sql .query-create-sql textarea#sql-editor {
+    grid-column: 2;
+    width: 100%;
+}
+.query-create-options {
+    align-items: center;
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.8rem 1.4rem;
+    margin: 0 0 0.9rem calc(var(--query-create-label-width) + var(--query-create-column-gap));
+    max-width: calc(52rem - var(--query-create-label-width) - var(--query-create-column-gap));
+}
+.query-create-options label {
+    align-items: center;
+    display: inline-flex;
+    gap: 0.35rem;
+    width: auto;
+}
+.query-create-options input[type=checkbox] {
+    margin: 0;
+}
+.query-create-option-note,
+.query-create-analysis-note {
+    color: #4f5b6d;
+    flex-basis: 100%;
+    font-size: 0.82rem;
+}
+.query-create-option-note {
+    margin: -0.45rem 0 0;
+}
+.query-create-analysis-note {
+    margin: 0;
+}
+.query-create-analysis {
+    margin-top: 0.8rem;
+}
+.query-create-submit {
+    margin-left: calc(var(--query-create-label-width) + var(--query-create-column-gap));
+    margin-bottom: 0.9rem;
+    margin-top: 1rem;
+}
+@media (max-width: 560px) {
+    .query-create-form {
+        --query-create-label-width: 1fr;
+        --query-create-column-gap: 0;
+    }
+    .query-create-field {
+        grid-template-columns: 1fr;
+        row-gap: 0.25rem;
+    }
+    .query-create-field label {
+        padding-top: 0;
+    }
+    form.sql .query-create-sql {
+        grid-template-columns: 1fr;
+    }
+    .query-create-sql .cm-editor,
+    form.sql .query-create-sql textarea#sql-editor {
+        grid-column: 1;
+    }
+    .query-create-options,
+    .query-create-submit {
+        margin-left: 0;
+    }
+}
+</style>

datasette/templates/_sql_parameter_scripts.html

@@ -27,16 +27,20 @@ window.datasetteSqlParameters = (() => {
     manager.section
       .querySelectorAll("[data-parameter-control]")
       .forEach((control) => {
-        manager.parameterState.set(control.name, controlState(control));
+        manager.parameterState.set(
+          control.dataset.parameterName,
+          controlState(control)
+        );
       });
   }
 
-  function createControl(parameter, id, state) {
+  function createControl(parameter, id, state, namePrefix) {
     const control = document.createElement(state.expanded ? "textarea" : "input");
     control.id = id;
-    control.name = parameter;
+    control.name = `${namePrefix || ""}${parameter}`;
     control.value = state.value;
     control.setAttribute("data-parameter-control", "");
+    control.dataset.parameterName = parameter;
     if (state.expanded) {
       control.rows = 5;
     } else {
@@ -53,10 +57,16 @@ window.datasetteSqlParameters = (() => {
     value,
     selectionStart
   ) {
-    const replacement = createControl(control.name, control.id, {
-      value: value === undefined ? control.value : value,
-      expanded: expand,
-    });
+    const parameter = control.dataset.parameterName;
+    const replacement = createControl(
+      parameter,
+      control.id,
+      {
+        value: value === undefined ? control.value : value,
+        expanded: expand,
+      },
+      manager.namePrefix
+    );
     button.textContent = expand ? "Collapse" : "Expand";
     button.setAttribute("aria-expanded", expand ? "true" : "false");
     control.replaceWith(replacement);
@@ -64,7 +74,7 @@ window.datasetteSqlParameters = (() => {
     if (selectionStart !== undefined && replacement.setSelectionRange) {
       replacement.setSelectionRange(selectionStart, selectionStart);
     }
-    manager.parameterState.set(replacement.name, controlState(replacement));
+    manager.parameterState.set(parameter, controlState(replacement));
   }
 
   function renderParameters(manager, parameters) {
@@ -99,7 +109,7 @@ window.datasetteSqlParameters = (() => {
       label.htmlFor = id;
       label.textContent = parameter;
 
-      const control = createControl(parameter, id, state);
+      const control = createControl(parameter, id, state, manager.namePrefix);
 
       row.append(label, control);
       if (manager.allowExpand) {
@@ -124,7 +134,10 @@ window.datasetteSqlParameters = (() => {
       if (!control.matches || !control.matches("[data-parameter-control]")) {
         return;
       }
-      manager.parameterState.set(control.name, controlState(control));
+      manager.parameterState.set(
+        control.dataset.parameterName,
+        controlState(control)
+      );
     });
 
     if (!manager.allowExpand) {
@@ -230,6 +243,7 @@ window.datasetteSqlParameters = (() => {
             ? section.dataset.allowExpand === "1"
             : false
           : options.allowExpand,
+      namePrefix: section ? section.dataset.parameterNamePrefix || "" : "",
       parameterState: new Map(),
     };
     if (section) {

datasette/templates/_sql_parameters.html

@@ -1,9 +1,10 @@
-<div id="{{ sql_parameters_section_id|default("sql-parameters-section") }}" class="sql-parameters-section" data-sql-parameters-section{% if sql_parameters_allow_expand|default(false) %} data-allow-expand="1"{% endif %}>
+{% set sql_parameter_name_prefix = sql_parameter_name_prefix|default("") %}
+<div id="{{ sql_parameters_section_id|default("sql-parameters-section") }}" class="sql-parameters-section" data-sql-parameters-section{% if sql_parameter_name_prefix %} data-parameter-name-prefix="{{ sql_parameter_name_prefix }}"{% endif %}{% if sql_parameters_allow_expand|default(false) %} data-allow-expand="1"{% endif %}>
     {% if parameter_names %}
         <h2>Parameters</h2>
         {% for parameter in parameter_names %}
             {% set parameter_id = (sql_parameter_id_prefix|default("qp")) ~ loop.index %}
-            <p class="sql-parameter-row"><label for="{{ parameter_id }}">{{ parameter }}</label> <input type="text" id="{{ parameter_id }}" name="{{ parameter }}" value="{{ parameter_values.get(parameter, "") }}" data-parameter-control>{% if sql_parameters_allow_expand|default(false) %} <button type="button" class="sql-parameter-toggle" data-parameter-toggle aria-controls="{{ parameter_id }}" aria-expanded="false">Expand</button>{% endif %}</p>
+            <p class="sql-parameter-row"><label for="{{ parameter_id }}">{{ parameter }}</label> <input type="text" id="{{ parameter_id }}" name="{{ sql_parameter_name_prefix }}{{ parameter }}" value="{{ parameter_values.get(parameter, "") }}" data-parameter-control data-parameter-name="{{ parameter }}">{% if sql_parameters_allow_expand|default(false) %} <button type="button" class="sql-parameter-toggle" data-parameter-toggle aria-controls="{{ parameter_id }}" aria-expanded="false">Expand</button>{% endif %}</p>
         {% endfor %}
     {% endif %}
 </div>

datasette/templates/_table.html

@@ -22,7 +22,7 @@
         </thead>
         <tbody>
         {% for row in display_rows %}
-            <tr>
+            <tr{% if row.pk_path is not none %} data-row="{{ row.row_path }}"{% if row.row_label %} data-row-label="{{ row.row_label }}"{% endif %}{% endif %}>
                 {% for cell in row %}
                     <td class="col-{{ cell.column|to_css_class }} type-{{ cell.value_type }}">{{ cell.value }}</td>
                 {% endfor %}

datasette/templates/allow_debug.html

@@ -3,29 +3,11 @@
 {% block title %}Debug allow rules{% endblock %}
 
 {% block extra_head %}
+{% include "_permission_ui_styles.html" %}
 <style>
-textarea {
-    height: 10em;
-    width: 95%;
-    box-sizing: border-box;
-    padding: 0.5em;
-    border: 2px dotted black;
-}
-.two-col {
-    display: inline-block;
-    width: 48%;
-}
-.two-col label {
-    width: 48%;
-}
 p.message-warning {
     white-space: pre-wrap;
 }
-@media only screen and (max-width: 576px) {
-    .two-col {
-        width: 100%;
-    }
-}
 </style>
 {% endblock %}
 
@@ -38,24 +20,28 @@ p.message-warning {
 
 <p>Use this tool to try out different actor and allow combinations. See <a href="https://docs.datasette.io/en/stable/authentication.html#defining-permissions-with-allow-blocks">Defining permissions with "allow" blocks</a> for documentation.</p>
 
-<form class="core" action="{{ urls.path('-/allow-debug') }}" method="get" style="margin-bottom: 1em">
-    <div class="two-col">
-        <p><label>Allow block</label></p>
-        <textarea name="allow">{{ allow_input }}</textarea>
-    </div>
-    <div class="two-col">
-        <p><label>Actor</label></p>
-        <textarea name="actor">{{ actor_input }}</textarea>
-    </div>
-    <div style="margin-top: 1em;">
-        <input type="submit" value="Apply allow block to actor">
-    </div>
-</form>
+<div class="permission-form">
+    <form class="core" action="{{ urls.path('-/allow-debug') }}" method="get">
+        <div class="permission-form-grid">
+            <div class="form-section">
+                <label for="allow-block">Allow block</label>
+                <textarea class="permission-textarea" id="allow-block" name="allow">{{ allow_input }}</textarea>
+            </div>
+            <div class="form-section">
+                <label for="allow-actor">Actor</label>
+                <textarea class="permission-textarea" id="allow-actor" name="actor">{{ actor_input }}</textarea>
+            </div>
+        </div>
+        <div class="form-actions">
+            <button type="submit" class="submit-btn">Apply allow block to actor</button>
+        </div>
+    </form>
 
-{% if error %}<p class="message-warning">{{ error }}</p>{% endif %}
+    {% if error %}<p class="message-warning permission-form-result">{{ error }}</p>{% endif %}
 
-{% if result == "True" %}<p class="message-info">Result: allow</p>{% endif %}
+    {% if result == "True" %}<p class="message-info permission-form-result">Result: allow</p>{% endif %}
 
-{% if result == "False" %}<p class="message-error">Result: deny</p>{% endif %}
+    {% if result == "False" %}<p class="message-error permission-form-result">Result: deny</p>{% endif %}
+</div>
 
 {% endblock %}

datasette/templates/api_explorer.html

@@ -3,7 +3,7 @@
 {% block title %}API Explorer{% endblock %}
 
 {% block extra_head %}
-<script src="{{ base_url }}-/static/json-format-highlight-1.0.1.js"></script>
+<script src="{{ static('json-format-highlight-1.0.1.js') }}"></script>
 {% endblock %}
 
 {% block content %}

datasette/templates/base.html

@@ -2,13 +2,13 @@
 <html lang="en">
 <head>
     <title>{% block title %}{% endblock %}</title>
-    <link rel="stylesheet" href="{{ urls.static('app.css') }}?{{ app_css_hash }}">
+    <link rel="stylesheet" href="{{ static('app.css') }}">
     <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
 {% for url in extra_css_urls %}
     <link rel="stylesheet" href="{{ url.url }}"{% if url.get("sri") %} integrity="{{ url.sri }}" crossorigin="anonymous"{% endif %}>
 {% endfor %}
 <script>window.datasetteVersion = '{{ datasette_version }}';</script>
-<script src="{{ urls.static('datasette-manager.js') }}" defer></script>
+<script src="{{ static('datasette-manager.js') }}" defer></script>
 {% for url in extra_js_urls %}
     <script {% if url.module %}type="module" {% endif %}src="{{ url.url }}"{% if url.get("sri") %} integrity="{{ url.sri }}" crossorigin="anonymous"{% endif %}></script>
 {% endfor %}
@@ -70,7 +70,7 @@
 {% endfor %}
 
 {% if select_templates %}<!-- Templates considered: {{ select_templates|join(", ") }} -->{% endif %}
-<script src="{{ urls.static('navigation-search.js') }}" defer></script>
+<script src="{{ static('navigation-search.js') }}" defer></script>
 <navigation-search url="{{ urls.path("/-/jump") }}"></navigation-search>
 </body>
 </html>

datasette/templates/database.html

@@ -6,6 +6,10 @@
 {{- super() -}}
 {% include "_codemirror.html" %}
 {% include "_sql_parameter_styles.html" %}
+{% if database_page_data.createTable %}
+<script>window._datasetteDatabaseData = {{ database_page_data|tojson }};</script>
+<script src="{{ static('edit-tools.js') }}" defer></script>
+{% endif %}
 {% endblock %}
 
 {% block body_class %}db db-{{ database|to_css_class }}{% endblock %}
@@ -72,7 +76,7 @@
 <div class="db-table">
     <h3><a href="{{ urls.table(database, table.name) }}">{{ table.name }}</a>{% if table.private %} 🔒{% endif %}{% if table.hidden %}<em> (hidden)</em>{% endif %}</h3>
     <p><em>{% for column in table.columns %}{{ column }}{% if not loop.last %}, {% endif %}{% endfor %}</em></p>
-    <p>{% if table.count is none %}Many rows{% elif table.count == count_limit + 1 %}&gt;{{ "{:,}".format(count_limit) }} rows{% else %}{{ "{:,}".format(table.count) }} row{% if table.count == 1 %}{% else %}s{% endif %}{% endif %}</p>
+    <p>{% if table.count is none %}Many rows{% elif table.count_truncated %}&gt;{{ "{:,}".format(table.count - 1) }} rows{% else %}{{ "{:,}".format(table.count) }} row{% if table.count == 1 %}{% else %}s{% endif %}{% endif %}</p>
 </div>
 {% endif %}
 {% endfor %}

datasette/templates/debug_actions.html

@@ -9,7 +9,7 @@
 {% include "_permissions_debug_tabs.html" %}
 
 <p style="margin-bottom: 2em;">
-  This Datasette instance has registered {{ data|length }} action{{ data|length != 1 and "s" or "" }}.
+  This Datasette instance has registered {{ data.actions|length }} action{{ data.actions|length != 1 and "s" or "" }}.
   Actions are used by the permission system to control access to different features.
 </p>
 
@@ -26,7 +26,7 @@
     </tr>
   </thead>
   <tbody>
-    {% for action in data %}
+    {% for action in data.actions %}
     <tr>
       <td><strong>{{ action.name }}</strong></td>
       <td>{% if action.abbr %}<code>{{ action.abbr }}</code>{% endif %}</td>

datasette/templates/debug_allowed.html

@@ -3,7 +3,7 @@
 {% block title %}Allowed Resources{% endblock %}
 
 {% block extra_head %}
-<script src="{{ base_url }}-/static/json-format-highlight-1.0.1.js"></script>
+<script src="{{ static('json-format-highlight-1.0.1.js') }}"></script>
 {% include "_permission_ui_styles.html" %}
 {% include "_debug_common_functions.html" %}
 {% endblock %}
@@ -49,7 +49,7 @@
 
         <div class="form-section">
             <label for="page_size">Page size:</label>
-            <input type="number" id="page_size" name="page_size" value="50" min="1" max="200" style="max-width: 100px;">
+            <input type="number" id="page_size" name="_size" value="50" min="1" max="200">
             <small>Number of results per page (max 200)</small>
         </div>
 
@@ -88,7 +88,7 @@ const hasDebugPermission = {{ 'true' if has_debug_permission else 'false' }};
 (function() {
     const params = populateFormFromURL();
     const action = params.get('action');
-    const page = params.get('page');
+    const page = params.get('_page');
     if (action) {
         fetchResults(page ? parseInt(page) : 1);
     }
@@ -102,14 +102,14 @@ async function fetchResults(page = 1) {
     const params = new URLSearchParams();
 
     for (const [key, value] of formData.entries()) {
-        if (value && key !== 'page_size') {
+        if (value && key !== '_size' && key !== '_page') {
             params.append(key, value);
         }
     }
 
     const pageSize = document.getElementById('page_size').value || '50';
-    params.append('page', page.toString());
-    params.append('page_size', pageSize);
+    params.append('_page', page.toString());
+    params.append('_size', pageSize);
 
     try {
         const response = await fetch('{{ urls.path("-/allowed.json") }}?' + params.toString(), {

datasette/templates/debug_autocomplete.html

@@ -0,0 +1,78 @@
+{% extends "base.html" %}
+
+{% block title %}Debug autocomplete{% endblock %}
+
+{% block extra_head %}
+{{ super() }}
+<script src="{{ static('autocomplete.js') }}" defer></script>
+{% endblock %}
+
+{% block content %}
+<h1>Debug autocomplete</h1>
+
+<form class="core debug-autocomplete-form" action="{{ urls.path('-/debug/autocomplete') }}" method="get">
+    <p>
+        <label for="debug-autocomplete-database">Database</label>
+        <input id="debug-autocomplete-database" type="text" name="database" value="{{ database_name or "" }}">
+    </p>
+    <p>
+        <label for="debug-autocomplete-table">Table</label>
+        <input id="debug-autocomplete-table" type="text" name="table" value="{{ table_name or "" }}">
+    </p>
+    <p><input type="submit" value="Open autocomplete"></p>
+</form>
+
+{% if error %}
+    <p class="message-error">{{ error }}</p>
+{% elif autocomplete_url %}
+    <h2>{{ database_name }} / {{ table_name }}</h2>
+    {% if label_column %}
+        <p>Label column: <code>{{ label_column }}</code></p>
+    {% else %}
+        <p>No label column detected. Results will use primary key values.</p>
+    {% endif %}
+    <div class="debug-autocomplete-demo">
+        <label for="debug-autocomplete-input">Search rows</label>
+        <datasette-autocomplete src="{{ autocomplete_url }}">
+            <input id="debug-autocomplete-input" type="text">
+        </datasette-autocomplete>
+    </div>
+    <h3>Selected row</h3>
+    <pre class="debug-autocomplete-selected" aria-live="polite">No row selected.</pre>
+    <script>
+    document.addEventListener("datasette-autocomplete-select", function (event) {
+        var output = document.querySelector(".debug-autocomplete-selected");
+        if (output) {
+            output.textContent = JSON.stringify(event.detail.row, null, 2);
+        }
+    });
+    </script>
+{% else %}
+    <h2>Suggested tables</h2>
+    {% if suggestions %}
+        <p>Showing up to five tables with a detected label column.</p>
+        <table class="rows-and-columns">
+            <thead>
+                <tr>
+                    <th>Database</th>
+                    <th>Table</th>
+                    <th>Label column</th>
+                </tr>
+            </thead>
+            <tbody>
+                {% for suggestion in suggestions %}
+                    <tr>
+                        <td>{{ suggestion.database }}</td>
+                        <td><a href="{{ suggestion.url }}">{{ suggestion.table }}</a></td>
+                        <td><code>{{ suggestion.label_column }}</code></td>
+                    </tr>
+                {% endfor %}
+            </tbody>
+        </table>
+    {% else %}
+        <p>No tables with detected label columns found.</p>
+    {% endif %}
+    <p>Scanned {{ scanned }} table{% if scanned != 1 %}s{% endif %}{% if reached_scan_limit %}; stopped at the 100 table scan limit{% endif %}.</p>
+{% endif %}
+
+{% endblock %}

datasette/templates/debug_check.html

@@ -1,9 +1,9 @@
 {% extends "base.html" %}
 
-{% block title %}Permission Check{% endblock %}
+{% block title %}Explain a permission decision{% endblock %}
 
 {% block extra_head %}
-<script src="{{ base_url }}-/static/json-format-highlight-1.0.1.js"></script>
+<script src="{{ static('json-format-highlight-1.0.1.js') }}"></script>
 {% include "_permission_ui_styles.html" %}
 {% include "_debug_common_functions.html" %}
 <style>
@@ -13,29 +13,35 @@
     border-radius: 5px;
 }
 #output.allowed {
-    background-color: #e8f5e9;
+    background-color: #f3fbf4;
     border: 2px solid #4caf50;
 }
 #output.denied {
-    background-color: #ffebee;
+    background-color: #fff7f7;
     border: 2px solid #f44336;
 }
 #output h2 {
     margin-top: 0;
 }
-#output .result-badge {
+#output h3 {
+    margin-bottom: 0.5em;
+}
+#output .result-badge,
+.effect-badge,
+.rule-status {
     display: inline-block;
-    padding: 0.3em 0.8em;
+    padding: 0.2em 0.5em;
     border-radius: 3px;
     font-weight: bold;
-    font-size: 1.1em;
 }
-#output .allowed-badge {
-    background-color: #4caf50;
+#output .allowed-badge,
+.effect-allow {
+    background-color: #2e7d32;
     color: white;
 }
-#output .denied-badge {
-    background-color: #f44336;
+#output .denied-badge,
+.effect-deny {
+    background-color: #c62828;
     color: white;
 }
 .details-section {
@@ -48,70 +54,130 @@
 .details-section dd {
     margin-left: 1em;
 }
+.explanation-section {
+    background: rgba(255, 255, 255, 0.75);
+    border: 1px solid #ddd;
+    border-radius: 4px;
+    margin-top: 1em;
+    padding: 0 1em 1em;
+}
+.rules-table {
+    border-collapse: collapse;
+    width: 100%;
+}
+.rules-table th,
+.rules-table td {
+    border-bottom: 1px solid #ddd;
+    padding: 0.5em;
+    text-align: left;
+    vertical-align: top;
+}
+.rule-status {
+    background: #e8f5e9;
+    color: #1b5e20;
+}
+.rule-ignored {
+    background: #eee;
+    color: #555;
+    font-weight: normal;
+}
+.requirement-allowed {
+    color: #1b5e20;
+}
+.requirement-denied {
+    color: #b71c1c;
+}
+@media only screen and (max-width: 576px) {
+    .rules-table,
+    .rules-table tbody,
+    .rules-table tr,
+    .rules-table td {
+        display: block;
+    }
+    .rules-table thead {
+        display: none;
+    }
+    .rules-table td::before {
+        content: attr(data-label) ": ";
+        font-weight: bold;
+    }
+}
 </style>
 {% endblock %}
 
 {% block content %}
-<h1>Permission check</h1>
+<h1>Explain a permission decision</h1>
 
 {% set current_tab = "check" %}
 {% include "_permissions_debug_tabs.html" %}
 
-<p>Use this tool to test permission checks for the current actor. It queries the <code>/-/check.json</code> API endpoint.</p>
-
-{% if request.actor %}
-<p>Current actor: <strong>{{ request.actor.get("id", "anonymous") }}</strong></p>
-{% else %}
-<p>Current actor: <strong>anonymous (not logged in)</strong></p>
-{% endif %}
+<p>Test an actor, action and resource. The result explains which rules matched, which specificity level won, and whether actor restrictions or required actions changed the verdict.</p>
 
 <div class="permission-form">
-    <form id="check-form" method="get" action="{{ urls.path("-/check") }}">
+    <form id="check-form" method="get" action="{{ urls.path('-/check') }}">
         <div class="form-section">
-            <label for="action">Action (permission name):</label>
+            <label for="actor">Actor JSON:</label>
+            <textarea class="permission-textarea" id="actor" name="actor">{{ actor_json }}</textarea>
+            <small>Use <code>null</code> for an anonymous actor. This actor is simulated; it does not change who you are signed in as.</small>
+        </div>
+
+        <div class="form-section">
+            <label for="action">Action:</label>
             <select id="action" name="action" required>
                 <option value="">Select an action...</option>
-                {% for action_name in sorted_actions %}
-                <option value="{{ action_name }}">{{ action_name }}</option>
+                {% for action in actions %}
+                <option value="{{ action.name }}">{{ action.name }}{% if action.description %} — {{ action.description }}{% endif %}</option>
                 {% endfor %}
             </select>
-            <small>The permission action to check</small>
+            <small id="action-help">The operation to evaluate</small>
         </div>
 
-        <div class="form-section">
-            <label for="parent">Parent resource (optional):</label>
+        <div class="form-section" id="parent-section">
+            <label for="parent">Parent resource:</label>
             <input type="text" id="parent" name="parent" placeholder="e.g., database name">
-            <small>For database-level permissions, specify the database name</small>
+            <small>The database or other parent resource</small>
         </div>
 
-        <div class="form-section">
-            <label for="child">Child resource (optional):</label>
-            <input type="text" id="child" name="child" placeholder="e.g., table name">
-            <small>For table-level permissions, specify the table name (requires parent)</small>
+        <div class="form-section" id="child-section">
+            <label for="child">Child resource:</label>
+            <input type="text" id="child" name="child" placeholder="e.g., table or query name">
+            <small>The table, query or other child resource</small>
         </div>
 
         <div class="form-actions">
-            <button type="submit" class="submit-btn" id="submit-btn">Check Permission</button>
+            <button type="submit" class="submit-btn" id="submit-btn">Explain decision</button>
         </div>
     </form>
 </div>
 
 <div id="output" style="display: none;">
     <h2>Result: <span class="result-badge" id="result-badge"></span></h2>
+    <p id="result-summary"></p>
 
     <dl class="details-section">
+        <dt>Actor:</dt>
+        <dd><code id="result-actor"></code></dd>
         <dt>Action:</dt>
-        <dd id="result-action"></dd>
-
-        <dt>Resource Path:</dt>
-        <dd id="result-resource"></dd>
-
-        <dt>Actor ID:</dt>
-        <dd id="result-actor"></dd>
-
-        <div id="additional-details"></div>
+        <dd><code id="result-action"></code></dd>
+        <dt>Resource:</dt>
+        <dd><code id="result-resource"></code></dd>
     </dl>
 
+    <section class="explanation-section">
+        <h3>Matching rules</h3>
+        <div id="matching-rules"></div>
+    </section>
+
+    <section class="explanation-section" id="restrictions-section">
+        <h3>Actor restrictions</h3>
+        <div id="restriction-results"></div>
+    </section>
+
+    <section class="explanation-section" id="requirements-section">
+        <h3>Required actions</h3>
+        <div id="requirement-results"></div>
+    </section>
+
     <details style="margin-top: 1em;">
         <summary style="cursor: pointer; font-weight: bold;">Raw JSON response</summary>
         <pre id="raw-json" style="margin-top: 1em; padding: 1em; background-color: #f5f5f5; border: 1px solid #ddd; border-radius: 3px; overflow-x: auto;"></pre>
@@ -119,152 +185,134 @@
 </div>
 
 <script>
+const actions = Object.fromEntries({{ actions|tojson }}.map(action => [action.name, action]));
 const form = document.getElementById('check-form');
 const output = document.getElementById('output');
 const submitBtn = document.getElementById('submit-btn');
+const actionSelect = document.getElementById('action');
+
+function updateResourceFields() {
+    const action = actions[actionSelect.value];
+    document.getElementById('parent-section').style.display = action && action.takes_parent ? 'block' : 'none';
+    document.getElementById('child-section').style.display = action && action.takes_child ? 'block' : 'none';
+    let help = action && action.description ? action.description : 'The operation to evaluate';
+    if (action && action.also_requires) {
+        help += `; also requires ${action.also_requires}`;
+    }
+    document.getElementById('action-help').textContent = help;
+}
 
 async function performCheck() {
     submitBtn.disabled = true;
-    submitBtn.textContent = 'Checking...';
-
-    const formData = new FormData(form);
-    const params = new URLSearchParams();
-
-    for (const [key, value] of formData.entries()) {
-        if (value) {
-            params.append(key, value);
-        }
-    }
+    submitBtn.textContent = 'Explaining...';
+    const params = new URLSearchParams(new FormData(form));
 
     try {
         const response = await fetch('{{ urls.path("-/check.json") }}?' + params.toString(), {
-            method: 'GET',
-            headers: {
-                'Accept': 'application/json',
-            }
+            headers: {'Accept': 'application/json'}
         });
-
         const data = await response.json();
-
         if (response.ok) {
             displayResult(data);
         } else {
             displayError(data);
         }
     } catch (error) {
-        alert('Error: ' + error.message);
+        displayError({error: error.message});
     } finally {
         submitBtn.disabled = false;
-        submitBtn.textContent = 'Check Permission';
+        submitBtn.textContent = 'Explain decision';
     }
 }
 
-// Populate form on initial load
-(function() {
-    const params = populateFormFromURL();
-    const action = params.get('action');
-    if (action) {
-        performCheck();
-    }
-})();
-
 function displayResult(data) {
     output.style.display = 'block';
-
-    // Set badge and styling
     const resultBadge = document.getElementById('result-badge');
-    if (data.allowed) {
-        output.className = 'allowed';
-        resultBadge.className = 'result-badge allowed-badge';
-        resultBadge.textContent = 'ALLOWED ✓';
-    } else {
-        output.className = 'denied';
-        resultBadge.className = 'result-badge denied-badge';
-        resultBadge.textContent = 'DENIED ✗';
-    }
-
-    // Basic details
-    document.getElementById('result-action').textContent = data.action || 'N/A';
-    document.getElementById('result-resource').textContent = data.resource?.path || '/';
-    document.getElementById('result-actor').textContent = data.actor_id || 'anonymous';
-
-    // Additional details
-    const additionalDetails = document.getElementById('additional-details');
-    additionalDetails.innerHTML = '';
-
-    if (data.reason !== undefined) {
-        const dt = document.createElement('dt');
-        dt.textContent = 'Reason:';
-        const dd = document.createElement('dd');
-        dd.textContent = data.reason || 'N/A';
-        additionalDetails.appendChild(dt);
-        additionalDetails.appendChild(dd);
-    }
-
-    if (data.source_plugin !== undefined) {
-        const dt = document.createElement('dt');
-        dt.textContent = 'Source Plugin:';
-        const dd = document.createElement('dd');
-        dd.textContent = data.source_plugin || 'N/A';
-        additionalDetails.appendChild(dt);
-        additionalDetails.appendChild(dd);
-    }
-
-    if (data.used_default !== undefined) {
-        const dt = document.createElement('dt');
-        dt.textContent = 'Used Default:';
-        const dd = document.createElement('dd');
-        dd.textContent = data.used_default ? 'Yes' : 'No';
-        additionalDetails.appendChild(dt);
-        additionalDetails.appendChild(dd);
-    }
-
-    if (data.depth !== undefined) {
-        const dt = document.createElement('dt');
-        dt.textContent = 'Depth:';
-        const dd = document.createElement('dd');
-        dd.textContent = data.depth;
-        additionalDetails.appendChild(dt);
-        additionalDetails.appendChild(dd);
-    }
-
-    // Raw JSON
+    output.className = data.allowed ? 'allowed' : 'denied';
+    resultBadge.className = `result-badge ${data.allowed ? 'allowed-badge' : 'denied-badge'}`;
+    resultBadge.textContent = data.allowed ? 'ALLOWED ✓' : 'DENIED ✗';
+    document.getElementById('result-summary').textContent = data.explanation.summary;
+    document.getElementById('result-actor').textContent = data.actor === null ? 'anonymous' : JSON.stringify(data.actor);
+    document.getElementById('result-action').textContent = data.action;
+    document.getElementById('result-resource').textContent = data.resource.path;
+    displayRules(data.explanation);
+    displayRestrictions(data.explanation.restrictions);
+    displayRequirements(data.explanation.required_actions);
     document.getElementById('raw-json').innerHTML = jsonFormatHighlight(data);
+}
 
-    // Scroll to output
-    output.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
+function displayRules(explanation) {
+    const container = document.getElementById('matching-rules');
+    if (!explanation.matched_rules.length) {
+        container.innerHTML = '<p>No rules matched. Datasette denies access when there is no matching rule.</p>';
+        return;
+    }
+    let html = '<table class="rules-table"><thead><tr><th>Effect</th><th>Scope</th><th>Source</th><th>Reason</th><th>Role in decision</th></tr></thead><tbody>';
+    for (const rule of explanation.matched_rules) {
+        const status = rule.decisive
+            ? '<span class="rule-status">Decisive</span>'
+            : `<span class="rule-status rule-ignored">${escapeHtml(rule.ignored_because)}</span>`;
+        html += '<tr>';
+        html += `<td data-label="Effect"><span class="effect-badge effect-${rule.effect}">${rule.effect.toUpperCase()}</span></td>`;
+        html += `<td data-label="Scope">${escapeHtml(rule.scope)}</td>`;
+        html += `<td data-label="Source"><code>${escapeHtml(rule.source || 'unknown')}</code></td>`;
+        html += `<td data-label="Reason">${escapeHtml(rule.reason || 'No reason supplied')}</td>`;
+        html += `<td data-label="Role in decision">${status}</td>`;
+        html += '</tr>';
+    }
+    container.innerHTML = html + '</tbody></table>';
+}
+
+function displayRestrictions(restrictions) {
+    const section = document.getElementById('restrictions-section');
+    const container = document.getElementById('restriction-results');
+    section.style.display = restrictions.length ? 'block' : 'none';
+    container.innerHTML = restrictions.map(restriction => {
+        const className = restriction.allowed ? 'requirement-allowed' : 'requirement-denied';
+        const verdict = restriction.allowed ? 'INCLUDED ✓' : 'EXCLUDED ✗';
+        return `<p class="${className}"><strong>${verdict}</strong> by <code>${escapeHtml(restriction.source || 'unknown')}</code>: ${escapeHtml(restriction.reason)}</p>`;
+    }).join('');
+}
+
+function displayRequirements(requirements) {
+    const section = document.getElementById('requirements-section');
+    const container = document.getElementById('requirement-results');
+    section.style.display = requirements.length ? 'block' : 'none';
+    container.innerHTML = requirements.map(requirement => {
+        const className = requirement.allowed ? 'requirement-allowed' : 'requirement-denied';
+        const verdict = requirement.allowed ? 'ALLOWED ✓' : 'DENIED ✗';
+        return `<p class="${className}"><strong>${escapeHtml(requirement.action)}: ${verdict}</strong> — ${escapeHtml(requirement.summary)}</p>`;
+    }).join('');
 }
 
 function displayError(data) {
     output.style.display = 'block';
     output.className = 'denied';
-
     const resultBadge = document.getElementById('result-badge');
     resultBadge.className = 'result-badge denied-badge';
     resultBadge.textContent = 'ERROR';
-
-    document.getElementById('result-action').textContent = 'N/A';
-    document.getElementById('result-resource').textContent = 'N/A';
-    document.getElementById('result-actor').textContent = 'N/A';
-
-    const additionalDetails = document.getElementById('additional-details');
-    additionalDetails.innerHTML = '<dt>Error:</dt><dd>' + (data.error || 'Unknown error') + '</dd>';
-
+    document.getElementById('result-summary').textContent = data.error || 'Unknown error';
+    document.getElementById('result-actor').textContent = '—';
+    document.getElementById('result-action').textContent = '—';
+    document.getElementById('result-resource').textContent = '—';
+    document.getElementById('matching-rules').innerHTML = '';
+    document.getElementById('restrictions-section').style.display = 'none';
+    document.getElementById('requirements-section').style.display = 'none';
     document.getElementById('raw-json').innerHTML = jsonFormatHighlight(data);
-
-    output.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
 }
 
-// Disable child input if parent is empty
-const parentInput = document.getElementById('parent');
-const childInput = document.getElementById('child');
-
-childInput.addEventListener('focus', () => {
-    if (!parentInput.value) {
-        alert('Please specify a parent resource first before adding a child resource.');
-        parentInput.focus();
-    }
+form.addEventListener('submit', event => {
+    event.preventDefault();
+    performCheck();
 });
-</script>
+actionSelect.addEventListener('change', updateResourceFields);
 
+(function initializeFromUrl() {
+    const params = populateFormFromURL();
+    updateResourceFields();
+    if (params.get('action')) {
+        performCheck();
+    }
+})();
+</script>
 {% endblock %}

datasette/templates/debug_permissions_playground.html

@@ -1,6 +1,6 @@
 {% extends "base.html" %}
 
-{% block title %}Debug permissions{% endblock %}
+{% block title %}Permission activity{% endblock %}
 
 {% block extra_head %}
 {% include "_permission_ui_styles.html" %}
@@ -20,60 +20,45 @@
 .check-action, .check-when, .check-result {
     font-size: 1.3em;
 }
-textarea {
-    height: 10em;
-    width: 95%;
-    box-sizing: border-box;
-    padding: 0.5em;
-    border: 2px dotted black;
-}
-.two-col {
-    display: inline-block;
-    width: 48%;
-}
-.two-col label {
-    width: 48%;
-}
-@media only screen and (max-width: 576px) {
-    .two-col {
-        width: 100%;
-    }
-}
 </style>
 {% endblock %}
 
 {% block content %}
-<h1>Permission playground</h1>
+<h1>Permission activity</h1>
 
 {% set current_tab = "permissions" %}
 {% include "_permissions_debug_tabs.html" %}
 
-<p>This tool lets you simulate an actor and a permission check for that actor.</p>
+<h2>Raw simulator</h2>
+
+<p>This form runs a hypothetical permission check and returns its raw explanation JSON. Use the <a href="{{ urls.path('-/check') }}">Explain tool</a> for a visual explanation of the same decision.</p>
 
 <div class="permission-form">
     <form action="{{ urls.path('-/permissions') }}" id="debug-post" method="post">
-        <div class="two-col">
-            <div class="form-section">
-                <label>Actor</label>
-                <textarea name="actor">{% if actor_input %}{{ actor_input }}{% else %}{"id": "root"}{% endif %}</textarea>
+        <div class="permission-form-grid">
+            <div>
+                <div class="form-section">
+                    <label for="activity-actor">Actor</label>
+                    <textarea class="permission-textarea" id="activity-actor" name="actor">{% if actor_input %}{{ actor_input }}{% else %}{"id": "root"}{% endif %}</textarea>
+                </div>
             </div>
-        </div>
-        <div class="two-col" style="vertical-align: top">
-            <div class="form-section">
-                <label for="permission">Action</label>
-                <select name="permission" id="permission">
-                    {% for permission in permissions %}
-                        <option value="{{ permission.name }}">{{ permission.name }}</option>
-                    {% endfor %}
-                </select>
-            </div>
-            <div class="form-section">
-                <label for="resource_1">Parent</label>
-                <input type="text" id="resource_1" name="resource_1" placeholder="e.g., database name">
-            </div>
-            <div class="form-section">
-                <label for="resource_2">Child</label>
-                <input type="text" id="resource_2" name="resource_2" placeholder="e.g., table name">
+            <div>
+                <div class="form-section">
+                    <label for="permission">Action</label>
+                    <select name="permission" id="permission">
+                        {% for permission in permissions %}
+                            <option value="{{ permission.name }}">{{ permission.name }}</option>
+                        {% endfor %}
+                    </select>
+                </div>
+                <div class="form-section">
+                    <label for="resource_1">Parent</label>
+                    <input type="text" id="resource_1" name="resource_1" placeholder="e.g., database name">
+                </div>
+                <div class="form-section">
+                    <label for="resource_2">Child</label>
+                    <input type="text" id="resource_2" name="resource_2" placeholder="e.g., table name">
+                </div>
             </div>
         </div>
         <div class="form-actions">
@@ -125,7 +110,7 @@ debugPost.addEventListener('submit', function(ev) {
 });
 </script>
 
-<h1>Recent permissions checks</h1>
+<h2>Recent permission checks</h2>
 
 <p>
     {% if filter != "all" %}<a href="?filter=all">All</a>{% else %}<strong>All</strong>{% endif %},

datasette/templates/debug_rules.html

@@ -3,7 +3,7 @@
 {% block title %}Permission Rules{% endblock %}
 
 {% block extra_head %}
-<script src="{{ base_url }}-/static/json-format-highlight-1.0.1.js"></script>
+<script src="{{ static('json-format-highlight-1.0.1.js') }}"></script>
 {% include "_permission_ui_styles.html" %}
 {% include "_debug_common_functions.html" %}
 {% endblock %}
@@ -37,7 +37,7 @@
 
         <div class="form-section">
             <label for="page_size">Page size:</label>
-            <input type="number" id="page_size" name="page_size" value="50" min="1" max="200" style="max-width: 100px;">
+            <input type="number" id="page_size" name="_size" value="50" min="1" max="200">
             <small>Number of results per page (max 200)</small>
         </div>
 
@@ -75,7 +75,7 @@ const submitBtn = document.getElementById('submit-btn');
 (function() {
     const params = populateFormFromURL();
     const action = params.get('action');
-    const page = params.get('page');
+    const page = params.get('_page');
     if (action) {
         fetchResults(page ? parseInt(page) : 1);
     }
@@ -89,14 +89,14 @@ async function fetchResults(page = 1) {
     const params = new URLSearchParams();
 
     for (const [key, value] of formData.entries()) {
-        if (value && key !== 'page_size') {
+        if (value && key !== '_size' && key !== '_page') {
             params.append(key, value);
         }
     }
 
     const pageSize = document.getElementById('page_size').value || '50';
-    params.append('page', page.toString());
-    params.append('page_size', pageSize);
+    params.append('_page', page.toString());
+    params.append('_size', pageSize);
 
     try {
         const response = await fetch('{{ urls.path("-/rules.json") }}?' + params.toString(), {

datasette/templates/execute_write.html

@@ -56,6 +56,11 @@ form.sql.core input[data-execute-write-submit]:disabled {
     cursor: not-allowed;
     opacity: 1;
 }
+.execute-write form.sql .sql-editor-min-lines .cm-content,
+.execute-write form.sql .sql-editor-min-lines .cm-gutter {
+    /* Four visible editor lines without adding blank lines to the SQL value. */
+    min-height: calc(5.6em + 8px);
+}
 .execute-write-disabled-reason {
     color: #4f5b6d;
     font-size: 0.85rem;
@@ -93,20 +98,25 @@ form.sql.core input[data-execute-write-submit]:disabled {
 {% endif %}
 
 <form class="sql core" action="{{ urls.database(database) }}/-/execute-write" method="post" data-analyze-url="{{ urls.database(database) }}/-/execute-write/analyze">
-    {% if write_template_tables %}
+    {% if write_create_table_template_sql or write_template_tables %}
         <div class="execute-write-template-menu">
             <details>
                 <summary>Start with a template</summary>
                 <p class="execute-write-template-controls">
-                    <label for="execute-write-template-table">Table</label>
-                    <select id="execute-write-template-table">
-                        {% for table_name, table in write_template_tables|dictsort %}
-                            <option value="{{ table_name }}"{% for operation, template_sql in table.templates|dictsort %} data-template-{{ operation }}-sql="{{ template_sql }}"{% endfor %}>{{ table_name }}</option>
+                    {% if write_create_table_template_sql %}
+                        <button type="button" data-sql-template="create" data-template-sql="{{ write_create_table_template_sql }}">Create table</button>
+                    {% endif %}
+                    {% if write_template_tables %}
+                        <label for="execute-write-template-table">{% if write_create_table_template_sql %}or table:{% else %}Table{% endif %}</label>
+                        <select id="execute-write-template-table">
+                            {% for table_name, table in write_template_tables|dictsort %}
+                                <option value="{{ table_name }}"{% for operation, template_sql in table.templates|dictsort %} data-template-{{ operation }}-sql="{{ template_sql }}"{% endfor %}>{{ table_name }}</option>
+                            {% endfor %}
+                        </select>
+                        {% for operation in write_template_operations %}
+                            <button type="button" data-sql-template="{{ operation.name }}">{{ operation.label }}</button>
                         {% endfor %}
-                    </select>
-                    {% for operation in write_template_operations %}
-                        <button type="button" data-sql-template="{{ operation.name }}">{{ operation.label }}</button>
-                    {% endfor %}
+                    {% endif %}
                 </p>
             </details>
         </div>
@@ -114,7 +124,7 @@ form.sql.core input[data-execute-write-submit]:disabled {
         <p class="message-warning execute-write-template-unavailable">There are no tables that you can currently edit.</p>
     {% endif %}
 
-    <p class="sql-editor"><textarea id="sql-editor" name="sql"{% if sql %} style="height: {{ sql.split("\n")|length + 2 }}em"{% endif %}>{{ sql }}</textarea></p>
+    <p class="sql-editor{% if not sql %} sql-editor-min-lines{% endif %}"><textarea id="sql-editor" name="sql"{% if sql %} style="height: {{ sql.split("\n")|length + 2 }}em"{% endif %}>{{ sql }}</textarea></p>
 
     {% set sql_parameters_section_id = "execute-write-parameters-section" %}
     {% set sql_parameters_allow_expand = true %}
@@ -159,19 +169,13 @@ form.sql.core input[data-execute-write-submit]:disabled {
     </p>
 </form>
 
-<script>
-const executeWriteSqlInput = document.querySelector("textarea#sql-editor");
-if (executeWriteSqlInput && !executeWriteSqlInput.value) {
-  executeWriteSqlInput.value = "\n\n\n";
-}
-</script>
-
 {% include "_codemirror_foot.html" %}
 {% include "_sql_parameter_scripts.html" %}
 {% include "_execute_write_analysis_scripts.html" %}
 
 <script>
 window.addEventListener("DOMContentLoaded", () => {
+  const executeWriteSqlInput = document.querySelector("textarea#sql-editor");
   const form = document.querySelector("form.sql.core");
   const analysisSection = document.querySelector("#execute-write-analysis-section");
   const submitButton = form
@@ -252,11 +256,12 @@ window.addEventListener("DOMContentLoaded", () => {
 });
 </script>
 
-{% if write_template_tables %}
+{% if write_create_table_template_sql or write_template_tables %}
 <script>
 window.addEventListener("DOMContentLoaded", () => {
   const tableSelect = document.querySelector("#execute-write-template-table");
   const templateButtons = document.querySelectorAll("[data-sql-template]");
+  const sqlInput = document.querySelector("textarea#sql-editor");
 
   function dataKey(operation) {
     return `template${operation.charAt(0).toUpperCase()}${operation.slice(1)}Sql`;
@@ -266,26 +271,59 @@ window.addEventListener("DOMContentLoaded", () => {
     return tableSelect ? tableSelect.options[tableSelect.selectedIndex] : null;
   }
 
-  function templateSql(operation) {
+  function templateSql(button) {
+    if (button.dataset.templateSql) {
+      return button.dataset.templateSql;
+    }
+    const operation = button.dataset.sqlTemplate;
     const option = selectedOption();
     return option ? option.dataset[dataKey(operation)] || "" : "";
   }
 
   function updateTemplateButtons() {
     templateButtons.forEach((button) => {
-      button.hidden = !templateSql(button.dataset.sqlTemplate);
+      button.hidden = !templateSql(button);
     });
   }
 
+  function updateSqlUrl(sql) {
+    if (!window.history || !window.history.replaceState) {
+      return;
+    }
+    const url = new URL(window.location.href);
+    url.searchParams.set("sql", sql);
+    window.history.replaceState(null, "", url.toString());
+  }
+
+  function setEditorSql(sql) {
+    if (window.editor) {
+      window.editor.dispatch({
+        changes: {
+          from: 0,
+          to: window.editor.state.doc.length,
+          insert: sql,
+        },
+        selection: { anchor: sql.length },
+      });
+      window.editor.focus();
+      if (sqlInput) {
+        sqlInput.value = sql;
+      }
+    } else if (sqlInput) {
+      sqlInput.value = sql;
+      sqlInput.dispatchEvent(new Event("input", { bubbles: true }));
+      sqlInput.focus();
+    }
+    updateSqlUrl(sql);
+  }
+
   templateButtons.forEach((button) => {
     button.addEventListener("click", () => {
-      const sql = templateSql(button.dataset.sqlTemplate);
+      const sql = templateSql(button);
       if (!sql) {
         return;
       }
-      const url = new URL(window.location.href);
-      url.searchParams.set("sql", sql);
-      window.location.href = url.toString();
+      setEditorSql(sql);
     });
   });
   if (tableSelect) {

datasette/templates/patterns.html

@@ -2,7 +2,7 @@
 <html lang="en">
 <head>
     <title>Datasette: Pattern Portfolio</title>
-    <link rel="stylesheet" href="{{ base_url }}-/static/app.css?{{ app_css_hash }}">
+    <link rel="stylesheet" href="{{ static('app.css') }}">
     <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
     <meta name="robots" content="noindex">
     <style></style>
@@ -202,9 +202,9 @@
     <h3>3 rows
         where characteristic_id = 2
     </h3>
-    <form class="filters" action="{{ base_url }}fixtures/roadside_attraction_characteristics" method="get">
+    <form class="core filters" action="{{ base_url }}fixtures/roadside_attraction_characteristics" method="get">
     <div class="search-row"><label for="_search">Search:</label><input id="_search" type="search" name="_search" value=""></div>
-        <div class="filter-row">
+        <div class="filter-row filter-controls-row">
             <div class="select-wrapper">
                 <select name="_filter_column_1">
                     <option value="">- remove filter -</option>
@@ -238,7 +238,7 @@
                 </select>
             </div><input type="text" name="_filter_value_1" class="filter-value" value="2">
         </div>
-    <div class="filter-row">
+    <div class="filter-row filter-controls-row">
         <div class="select-wrapper">
             <select name="_filter_column">
                 <option value="">- column -</option>
@@ -272,8 +272,8 @@
             </select>
         </div><input type="text" name="_filter_value" class="filter-value">
     </div>
-    <div class="filter-row">
-            <div class="select-wrapper small-screen-only">
+    <div class="filter-row filter-actions-row">
+            <div class="select-wrapper">
                 <select name="_sort" id="sort_by">
                     <option value="">Sort...</option>
                     <option value="rowid" selected>Sort by rowid</option>
@@ -281,8 +281,8 @@
                     <option value="characteristic_id">Sort by characteristic_id</option>
                 </select>
             </div>
-            <label class="sort_by_desc small-screen-only"><input type="checkbox" name="_sort_by_desc"> descending</label>
-        <input type="submit" value="Apply">
+            <label class="sort_by_desc"><input type="checkbox" name="_sort_by_desc"> descending</label>
+        <input type="submit" value="Apply filters">
     </div>
   </form>
 

datasette/templates/query_create.html

@@ -6,139 +6,7 @@
 {{- super() -}}
 {% include "_codemirror.html" %}
 {% include "_execute_write_analysis_styles.html" %}
-<style>
-.query-create-page {
-    max-width: 64rem;
-}
-.query-create-form {
-    --query-create-label-width: clamp(7rem, 18vw, 10rem);
-    --query-create-column-gap: 0.8rem;
-    --query-create-control-width: minmax(16rem, 1fr);
-}
-.query-create-fields {
-    margin: 0 0 0.85rem;
-    max-width: 52rem;
-}
-.query-create-field {
-    align-items: start;
-    column-gap: var(--query-create-column-gap);
-    display: grid;
-    grid-template-columns: var(--query-create-label-width) var(--query-create-control-width);
-    margin: 0 0 0.65rem;
-}
-.query-create-field label {
-    padding-top: 0.55rem;
-    width: auto;
-}
-.query-create-field input[type=text],
-.query-create-field textarea {
-    box-sizing: border-box;
-    width: 100%;
-}
-form.sql .query-create-field textarea {
-    width: 100%;
-}
-.query-create-url-control {
-    align-items: center;
-    box-sizing: border-box;
-    display: grid;
-    gap: 0.35rem;
-    grid-template-columns: max-content minmax(12rem, 1fr);
-    width: 100%;
-}
-.query-create-url-prefix {
-    color: #4f5b6d;
-    font-family: var(--font-monospace, monospace);
-    white-space: nowrap;
-}
-.query-create-url-control input[type=text] {
-    border: 1px solid #ccc;
-    border-radius: 3px;
-}
-.query-create-field textarea {
-    border: 1px solid #ccc;
-    border-radius: 3px;
-    display: block;
-    font-family: Helvetica, sans-serif;
-    font-size: 1em;
-    min-height: 5rem;
-    padding: 9px 4px;
-    resize: vertical;
-}
-form.sql .query-create-sql {
-    column-gap: var(--query-create-column-gap);
-    display: grid;
-    grid-template-columns: var(--query-create-label-width) var(--query-create-control-width);
-    margin: 0.9rem 0 0.75rem;
-    max-width: 52rem;
-}
-.query-create-sql .cm-editor,
-form.sql .query-create-sql textarea#sql-editor {
-    grid-column: 2;
-    width: 100%;
-}
-.query-create-options {
-    align-items: center;
-    display: flex;
-    flex-wrap: wrap;
-    gap: 0.8rem 1.4rem;
-    margin: 0 0 0.9rem calc(var(--query-create-label-width) + var(--query-create-column-gap));
-    max-width: calc(52rem - var(--query-create-label-width) - var(--query-create-column-gap));
-}
-.query-create-options label {
-    align-items: center;
-    display: inline-flex;
-    gap: 0.35rem;
-    width: auto;
-}
-.query-create-options input[type=checkbox] {
-    margin: 0;
-}
-.query-create-option-note,
-.query-create-analysis-note {
-    color: #4f5b6d;
-    flex-basis: 100%;
-    font-size: 0.82rem;
-}
-.query-create-option-note {
-    margin: -0.45rem 0 0;
-}
-.query-create-analysis-note {
-    margin: 0;
-}
-.query-create-analysis {
-    margin-top: 0.8rem;
-}
-.query-create-submit {
-    margin-left: calc(var(--query-create-label-width) + var(--query-create-column-gap));
-    margin-bottom: 0.9rem;
-    margin-top: 1rem;
-}
-@media (max-width: 560px) {
-    .query-create-form {
-        --query-create-label-width: 1fr;
-        --query-create-column-gap: 0;
-    }
-    .query-create-field {
-        grid-template-columns: 1fr;
-        row-gap: 0.25rem;
-    }
-    .query-create-field label {
-        padding-top: 0;
-    }
-    form.sql .query-create-sql {
-        grid-template-columns: 1fr;
-    }
-    .query-create-sql .cm-editor,
-    form.sql .query-create-sql textarea#sql-editor {
-        grid-column: 1;
-    }
-    .query-create-options,
-    .query-create-submit {
-        margin-left: 0;
-    }
-}
-</style>
+{% include "_query_form_styles.html" %}
 {% endblock %}
 
 {% block body_class %}query-create db-{{ database|to_css_class }}{% endblock %}

datasette/templates/query_delete.html

@@ -0,0 +1,82 @@
+{% extends "base.html" %}
+
+{% block title %}Delete query: {{ query.name }}{% endblock %}
+
+{% block extra_head %}
+{{- super() -}}
+<style>
+.query-delete-page {
+    max-width: 48rem;
+}
+.query-delete-summary {
+    background-color: #f7f7f9;
+    border: 1px solid #d7dde5;
+    border-radius: 4px;
+    margin: 0.75rem 0 1.25rem;
+    padding: 0.75rem 1rem;
+}
+.query-delete-summary dt {
+    color: #4f5b6d;
+    font-size: 0.82rem;
+    font-weight: 700;
+}
+.query-delete-summary dd {
+    margin: 0 0 0.6rem;
+}
+.query-delete-summary dd pre {
+    margin: 0.2rem 0 0;
+    white-space: pre-wrap;
+}
+.query-delete-actions {
+    align-items: center;
+    display: flex;
+    gap: 1rem;
+}
+.query-delete-form input[type=submit] {
+    background: linear-gradient(180deg, #d73a31 0%, #b42318 100%);
+    border-color: #b42318;
+    font-weight: 700;
+}
+.query-delete-form input[type=submit]:hover,
+.query-delete-form input[type=submit]:focus {
+    background: linear-gradient(180deg, #c3342b 0%, #971c14 100%);
+    border-color: #971c14;
+}
+</style>
+{% endblock %}
+
+{% block body_class %}query-delete db-{{ database|to_css_class }}{% endblock %}
+
+{% block crumbs %}
+{{ crumbs.nav(request=request, database=database) }}
+{% endblock %}
+
+{% block content %}
+
+<div class="query-delete-page">
+
+<h1 style="padding-left: 10px; border-left: 10px solid #{{ database_color }}">Delete query: {{ query.title or query.name }}</h1>
+
+<p>Are you sure you want to delete this saved query? This cannot be undone.</p>
+
+<dl class="query-delete-summary">
+    <dt>URL</dt>
+    <dd><a href="{{ query_url }}">{{ query_url }}</a></dd>
+    {% if query.description %}
+        <dt>Description</dt>
+        <dd>{{ query.description }}</dd>
+    {% endif %}
+    <dt>SQL</dt>
+    <dd><pre>{{ query.sql }}</pre></dd>
+</dl>
+
+<form class="core query-delete-form" action="{{ query_url }}/-/delete" method="post">
+    <p class="query-delete-actions">
+        <input type="submit" value="Delete query">
+        <a href="{{ query_url }}">Cancel</a>
+    </p>
+</form>
+
+</div>
+
+{% endblock %}

datasette/templates/query_edit.html

@@ -0,0 +1,133 @@
+{% extends "base.html" %}
+
+{% block title %}Edit query: {{ name }}{% endblock %}
+
+{% block extra_head %}
+{{- super() -}}
+{% include "_codemirror.html" %}
+{% include "_execute_write_analysis_styles.html" %}
+{% include "_query_form_styles.html" %}
+{% endblock %}
+
+{% block body_class %}query-edit db-{{ database|to_css_class }}{% endblock %}
+
+{% block crumbs %}
+{{ crumbs.nav(request=request, database=database) }}
+{% endblock %}
+
+{% block content %}
+
+<div class="query-create-page">
+
+<h1 style="padding-left: 10px; border-left: 10px solid #{{ database_color }}">Edit query: {{ title or name }}</h1>
+
+<form class="sql core query-create-form" action="{{ query_url }}/-/edit" method="post" data-analyze-url="{{ urls.database(database) }}/-/queries/analyze">
+    <div class="query-create-fields">
+        <p class="query-create-field"><label for="query-title">Title</label> <input id="query-title" name="title" type="text" value="{{ title or "" }}"></p>
+        <p class="query-create-field"><label>URL</label> <span class="query-create-url-static">{{ query_url }}</span></p>
+        <p class="query-create-field"><label for="query-description">Description</label> <textarea id="query-description" name="description" rows="3">{{ description or "" }}</textarea></p>
+    </div>
+
+    <p class="query-create-sql sql-editor"><textarea id="sql-editor" name="sql"{% if sql %} style="height: {{ sql.split("\n")|length + 2 }}em"{% endif %}>{{ sql }}</textarea></p>
+
+    <p class="query-create-options">
+        <span class="query-create-analysis-note" data-query-create-analysis-note aria-live="polite">{% if analysis_error %}This query cannot be saved until the SQL is valid.{% elif not has_sql %}Enter SQL to analyze this query.{% elif analysis_is_write %}This query updates data in the database.{% else %}This is a read-only query.{% endif %}</span>
+        <input type="hidden" name="is_private" value="0">
+        <label><input type="checkbox" name="is_private" value="1"{% if is_private %} checked{% endif %}> Private</label>
+        <span class="query-create-option-note">Queries marked private can only be seen and edited by you, their owner.</span>
+    </p>
+    <p class="query-create-submit"><input type="submit" value="Save changes" data-query-create-submit{% if save_disabled %} disabled{% endif %}> <a href="{{ query_url }}">Cancel</a></p>
+
+    <div class="query-create-analysis" id="query-create-analysis-section"{% if not has_sql %} hidden{% endif %}>
+        {% if has_sql %}
+            <h2>Query operations</h2>
+            {% if analysis_error %}
+                <p class="message-error">{{ analysis_error }}</p>
+            {% elif analysis_rows %}
+                <div class="table-wrapper"><table class="execute-write-analysis">
+                    <thead>
+                        <tr>
+                            <th scope="col">Operation</th>
+                            <th scope="col">Database</th>
+                            <th scope="col">Table</th>
+                            <th scope="col">Required permission</th>
+                            <th scope="col">Allowed</th>
+                        </tr>
+                    </thead>
+                    <tbody>
+                        {% for row in analysis_rows %}
+                            <tr>
+                                <td><code>{{ row.operation }}</code></td>
+                                <td><code>{{ row.database }}</code></td>
+                                <td><code>{{ row.table }}</code></td>
+                                <td>{% if row.required_permission %}<code>{{ row.required_permission }}</code>{% else %}<span class="execute-write-analysis-na">n/a</span>{% endif %}</td>
+                                <td>{% if row.allowed is none %}<span class="execute-write-analysis-na">n/a</span>{% elif row.allowed %}<span class="execute-write-analysis-allowed">yes</span>{% else %}<span class="execute-write-analysis-denied">no</span>{% endif %}</td>
+                            </tr>
+                        {% endfor %}
+                    </tbody>
+                </table></div>
+            {% else %}
+                <p>Analysis will show each affected table and required permission.</p>
+            {% endif %}
+        {% endif %}
+    </div>
+</form>
+
+</div>
+
+{% include "_codemirror_foot.html" %}
+{% include "_sql_parameter_scripts.html" %}
+{% include "_execute_write_analysis_scripts.html" %}
+
+<script>
+window.addEventListener("DOMContentLoaded", () => {
+  const form = document.querySelector("form.sql.core");
+  const analysisSection = document.querySelector("#query-create-analysis-section");
+  const submitButton = form
+    ? form.querySelector("[data-query-create-submit]")
+    : null;
+  const analysisNote = form
+    ? form.querySelector("[data-query-create-analysis-note]")
+    : null;
+
+  function updateAnalysisNote(data) {
+    if (!analysisNote) {
+      return;
+    }
+    if (data.analysis_error) {
+      analysisNote.textContent = "This query cannot be saved until the SQL is valid.";
+    } else if (data.has_sql === false) {
+      analysisNote.textContent = "Enter SQL to analyze this query.";
+    } else if (data.analysis_is_write) {
+      analysisNote.textContent = "This query updates data in the database.";
+    } else {
+      analysisNote.textContent = "This is a read-only query.";
+    }
+  }
+
+  window.datasetteSqlParameters.setupSqlParameterRefresh({
+    form,
+    url: form.dataset.analyzeUrl,
+    renderParameters: false,
+    onData(data) {
+      window.datasetteSqlAnalysis.renderAnalysis(analysisSection, data);
+      if (submitButton) {
+        submitButton.disabled = data.save_disabled;
+      }
+      updateAnalysisNote(data);
+    },
+    onError(error) {
+      window.datasetteSqlAnalysis.renderAnalysis(analysisSection, {
+        analysis_error: error.message,
+        analysis_rows: [],
+      });
+      if (submitButton) {
+        submitButton.disabled = true;
+      }
+      updateAnalysisNote({ analysis_error: error.message });
+    },
+  });
+});
+</script>
+
+{% endblock %}

datasette/templates/query_list.html

@@ -205,32 +205,32 @@
 
 <h1 style="padding-left: 10px; border-left: 10px solid #{% if database_color %}{{ database_color }}{% else %}666{% endif %}">Queries</h1>
 
-<form class="query-list-filters core" action="{{ query_list_path }}" method="get">
-    <p class="query-list-search">
-        <label for="query-search">Search</label>
-        <input id="query-search" type="search" name="q" value="{{ filters.q }}">
-        {% if filters.is_write %}<input type="hidden" name="is_write" value="{{ filters.is_write }}">{% endif %}
-        {% if filters.is_private %}<input type="hidden" name="is_private" value="{{ filters.is_private }}">{% endif %}
-        {% if filters.source %}<input type="hidden" name="source" value="{{ filters.source }}">{% endif %}
-        {% if filters.owner_id %}<input type="hidden" name="owner_id" value="{{ filters.owner_id }}">{% endif %}
-        <button type="submit">Search</button>
-    </p>
-</form>
-
-<nav class="query-list-facets" aria-label="Query filters">
-    {% for facet in facets %}
-        <section class="query-list-facet">
-            <h2>{{ facet.title }}</h2>
-            <ul>
-                {% for item in facet["items"] %}
-                    <li>{% if item.href %}<a class="query-list-facet-link{% if item.active %} query-list-facet-link-active{% endif %}" href="{{ item.href }}"{% if item.active %} aria-current="true"{% endif %}>{% else %}<span class="query-list-facet-link query-list-facet-disabled">{% endif %}<span>{{ item.label }}</span><span class="query-list-facet-count">{{ item.count }}</span>{% if item.href %}</a>{% else %}</span>{% endif %}</li>
-                {% endfor %}
-            </ul>
-        </section>
-    {% endfor %}
-</nav>
-
 {% if queries %}
+    <form class="query-list-filters core" action="{{ query_list_path }}" method="get">
+        <p class="query-list-search">
+            <label for="query-search">Search</label>
+            <input id="query-search" type="search" name="q" value="{{ filters.q }}">
+            {% if filters.is_write %}<input type="hidden" name="is_write" value="{{ filters.is_write }}">{% endif %}
+            {% if filters.is_private %}<input type="hidden" name="is_private" value="{{ filters.is_private }}">{% endif %}
+            {% if filters.source %}<input type="hidden" name="source" value="{{ filters.source }}">{% endif %}
+            {% if filters.owner_id %}<input type="hidden" name="owner_id" value="{{ filters.owner_id }}">{% endif %}
+            <button type="submit">Search</button>
+        </p>
+    </form>
+
+    <nav class="query-list-facets" aria-label="Query filters">
+        {% for facet in facets %}
+            <section class="query-list-facet">
+                <h2>{{ facet.title }}</h2>
+                <ul>
+                    {% for item in facet["items"] %}
+                        <li>{% if item.href %}<a class="query-list-facet-link{% if item.active %} query-list-facet-link-active{% endif %}" href="{{ item.href }}"{% if item.active %} aria-current="true"{% endif %}>{% else %}<span class="query-list-facet-link query-list-facet-disabled">{% endif %}<span>{{ item.label }}</span><span class="query-list-facet-count">{{ item.count }}</span>{% if item.href %}</a>{% else %}</span>{% endif %}</li>
+                    {% endfor %}
+                </ul>
+            </section>
+        {% endfor %}
+    </nav>
+
     <div class="table-wrapper"><table class="query-list-results">
         <thead>
             <tr>

datasette/templates/row.html

@@ -4,6 +4,13 @@
 
 {% block extra_head %}
 {{- super() -}}
+{% if row_mutation_ui %}
+<script>window._datasetteTableData = {{ table_page_data|tojson }};</script>
+{% if table_page_data.foreignKeys %}
+<script src="{{ static('autocomplete.js') }}" defer></script>
+{% endif %}
+<script src="{{ static('edit-tools.js') }}" defer></script>
+{% endif %}
 <style>
 @media only screen and (max-width: 576px) {
 {% for column in columns %}

datasette/templates/table.html

@@ -1,12 +1,17 @@
 {% extends "base.html" %}
 
-{% block title %}{{ database }}: {{ table }}: {% if count or count == 0 %}{{ "{:,}".format(count) }} row{% if count == 1 %}{% else %}s{% endif %}{% endif %}{% if human_description_en %} {{ human_description_en }}{% endif %}{% endblock %}
+{% block title %}{{ database }}: {{ table }}: {% if count_truncated %}>{{ "{:,}".format(count - 1) }} rows{% elif count or count == 0 %}{{ "{:,}".format(count) }} row{% if count == 1 %}{% else %}s{% endif %}{% endif %}{% if human_description_en %} {{ human_description_en }}{% endif %}{% endblock %}
 
 {% block extra_head %}
 {{- super() -}}
-<script src="{{ urls.static('column-chooser.js') }}" defer></script>
-<script src="{{ urls.static('table.js') }}" defer></script>
-<script src="{{ urls.static('mobile-column-actions.js') }}" defer></script>
+<script>window._datasetteTableData = {{ table_page_data|tojson }};</script>
+<script src="{{ static('column-chooser.js') }}" defer></script>
+{% if table_page_data.foreignKeys %}
+<script src="{{ static('autocomplete.js') }}" defer></script>
+{% endif %}
+<script src="{{ static('edit-tools.js') }}" defer></script>
+<script src="{{ static('table.js') }}" defer></script>
+<script src="{{ static('mobile-column-actions.js') }}" defer></script>
 <script>DATASETTE_ALLOW_FACET = {{ datasette_allow_facet }};</script>
 <style>
 @media only screen and (max-width: 576px) {
@@ -43,19 +48,19 @@
 
 {% if count or human_description_en %}
     <h3>
-        {% if count == count_limit + 1 %}&gt;{{ "{:,}".format(count_limit) }} rows
+        {% if count_truncated %}&gt;{{ "{:,}".format(count - 1) }} rows
         {% if allow_execute_sql and query.sql %} <a class="count-sql" style="font-size: 0.8em;" href="{{ urls.database_query(database, count_sql) }}">count all</a>{% endif %}
         {% elif count or count == 0 %}{{ "{:,}".format(count) }} row{% if count == 1 %}{% else %}s{% endif %}{% endif %}
         {% if human_description_en %}{{ human_description_en }}{% endif %}
     </h3>
 {% endif %}
 
-<form class="core" class="filters" action="{{ urls.table(database, table) }}" method="get">
+<form class="core filters" action="{{ urls.table(database, table) }}" method="get">
     {% if supports_search %}
         <div class="search-row"><label for="_search">Search:</label><input id="_search" type="search" name="_search" value="{{ search }}"></div>
     {% endif %}
     {% for column, lookup, value in filters.selections() %}
-        <div class="filter-row">
+        <div class="filter-row filter-controls-row">
             <div class="select-wrapper">
                 <select name="_filter_column_{{ loop.index }}">
                     <option value="">- remove filter -</option>
@@ -72,7 +77,7 @@
             </div><input type="text" name="_filter_value_{{ loop.index }}" class="filter-value" value="{{ value }}">
         </div>
     {% endfor %}
-    <div class="filter-row">
+    <div class="filter-row filter-controls-row">
         <div class="select-wrapper">
             <select name="_filter_column">
                 <option value="">- column -</option>
@@ -88,9 +93,9 @@
             </select>
         </div><input type="text" name="_filter_value" class="filter-value">
     </div>
-    <div class="filter-row">
+    <div class="filter-row filter-actions-row">
         {% if is_sortable %}
-            <div class="select-wrapper small-screen-only">
+            <div class="select-wrapper">
                 <select name="_sort" id="sort_by">
                     <option value="">Sort...</option>
                     {% for column in display_columns %}
@@ -100,12 +105,12 @@
                     {% endfor %}
                 </select>
             </div>
-            <label class="sort_by_desc small-screen-only"><input type="checkbox" name="_sort_by_desc"{% if sort_desc %} checked{% endif %}> descending</label>
+            <label class="sort_by_desc"><input type="checkbox" name="_sort_by_desc" tabindex="0"{% if sort_desc %} checked{% endif %}> descending</label>
         {% endif %}
         {% for key, value in form_hidden_args %}
             <input type="hidden" name="{{ key }}" value="{{ value }}">
         {% endfor %}
-        <input type="submit" value="Apply">
+        <input type="submit" value="Apply filters" tabindex="0">
     </div>
 </form>
 
@@ -158,6 +163,19 @@ window._setColumnTypeData = {{ set_column_type_ui|tojson }};
 </script>
 {% endif %}
 
+{% if table_insert_ui %}
+<div class="table-row-toolbar">
+    <button type="button" class="core table-insert-row" data-table-action="insert-row">
+        <svg class="row-inline-action-icon" aria-hidden="true" xmlns="http://www.w3.org/2000/svg" width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+            <rect width="18" height="18" x="3" y="3" rx="2"></rect>
+            <path d="M8 12h8"></path>
+            <path d="M12 8v8"></path>
+        </svg>
+        <span>Insert row</span>
+    </button>
+</div>
+{% endif %}
+
 {% include custom_table_templates %}
 
 {% if next_url %}

datasette/tokens.py

@@ -10,7 +10,7 @@ from __future__ import annotations
 
 import dataclasses
 import time
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING
 
 import itsdangerous
 
@@ -18,6 +18,21 @@ if TYPE_CHECKING:
     from datasette.app import Datasette
 
 
+class TokenInvalid(Exception):
+    """
+    Raised by a TokenHandler when a token it recognizes is invalid -
+    for example a bad signature, malformed payload or expired token.
+
+    Datasette responds to this with an HTTP 401 error. Handlers should
+    return None instead for tokens they do not recognize at all, so that
+    other registered handlers get a chance to verify them.
+    """
+
+    def __init__(self, message="Invalid token"):
+        self.message = message
+        super().__init__(message)
+
+
 @dataclasses.dataclass
 class TokenRestrictions:
     """
@@ -35,24 +50,24 @@ class TokenRestrictions:
     database: dict[str, list[str]] = dataclasses.field(default_factory=dict)
     resource: dict[str, dict[str, list[str]]] = dataclasses.field(default_factory=dict)
 
-    def allow_all(self, action: str) -> "TokenRestrictions":
+    def allow_all(self, action: str) -> TokenRestrictions:
         """Allow an action across all databases and resources."""
         self.all.append(action)
         return self
 
-    def allow_database(self, database: str, action: str) -> "TokenRestrictions":
+    def allow_database(self, database: str, action: str) -> TokenRestrictions:
         """Allow an action on a specific database."""
         self.database.setdefault(database, []).append(action)
         return self
 
     def allow_resource(
         self, database: str, resource: str, action: str
-    ) -> "TokenRestrictions":
+    ) -> TokenRestrictions:
         """Allow an action on a specific resource within a database."""
         self.resource.setdefault(database, {}).setdefault(resource, []).append(action)
         return self
 
-    def abbreviated(self, datasette: "Datasette") -> Optional[dict]:
+    def abbreviated(self, datasette: Datasette) -> dict | None:
         """
         Return the abbreviated ``_r`` dictionary shape for this set of
         restrictions, using action abbreviations registered with ``datasette``.
@@ -97,19 +112,23 @@ class TokenHandler:
 
     async def create_token(
         self,
-        datasette: "Datasette",
+        datasette: Datasette,
         actor_id: str,
         *,
-        expires_after: Optional[int] = None,
-        restrictions: Optional[TokenRestrictions] = None,
+        expires_after: int | None = None,
+        restrictions: TokenRestrictions | None = None,
     ) -> str:
         """Create and return a token string for the given actor."""
         raise NotImplementedError
 
-    async def verify_token(self, datasette: "Datasette", token: str) -> Optional[dict]:
+    async def verify_token(self, datasette: Datasette, token: str) -> dict | None:
         """
-        Verify a token and return an actor dict, or None if this handler
-        does not recognize the token.
+        Verify a token and return an actor dict.
+
+        Return None if this handler does not recognize the token at all,
+        so other handlers can try it. Raise TokenInvalid if the token is
+        recognized but invalid (bad signature, malformed, expired) - the
+        request will fail with a 401 error.
         """
         raise NotImplementedError
 
@@ -123,11 +142,11 @@ class SignedTokenHandler(TokenHandler):
 
     async def create_token(
         self,
-        datasette: "Datasette",
+        datasette: Datasette,
         actor_id: str,
         *,
-        expires_after: Optional[int] = None,
-        restrictions: Optional[TokenRestrictions] = None,
+        expires_after: int | None = None,
+        restrictions: TokenRestrictions | None = None,
     ) -> str:
         if not datasette.setting("allow_signed_tokens"):
             raise ValueError(
@@ -144,32 +163,35 @@ class SignedTokenHandler(TokenHandler):
                 token["_r"] = abbreviated
         return "dstok_{}".format(datasette.sign(token, namespace="token"))
 
-    async def verify_token(self, datasette: "Datasette", token: str) -> Optional[dict]:
+    async def verify_token(self, datasette: Datasette, token: str) -> dict | None:
         prefix = "dstok_"
 
-        if not datasette.setting("allow_signed_tokens"):
+        if not token.startswith(prefix):
+            # Not one of our tokens - leave it for other handlers
             return None
 
+        if not datasette.setting("allow_signed_tokens"):
+            raise TokenInvalid(
+                "Signed tokens are not enabled for this Datasette instance"
+            )
+
         max_signed_tokens_ttl = datasette.setting("max_signed_tokens_ttl")
 
-        if not token.startswith(prefix):
-            return None
-
         raw = token[len(prefix) :]
         try:
             decoded = datasette.unsign(raw, namespace="token")
         except itsdangerous.BadSignature:
-            return None
+            raise TokenInvalid("Invalid token signature")
 
         if "t" not in decoded:
-            return None
+            raise TokenInvalid("Invalid token: no timestamp")
         created = decoded["t"]
         if not isinstance(created, int):
-            return None
+            raise TokenInvalid("Invalid token: invalid timestamp")
 
         duration = decoded.get("d")
         if duration is not None and not isinstance(duration, int):
-            return None
+            raise TokenInvalid("Invalid token: invalid duration")
 
         if (duration is None and max_signed_tokens_ttl) or (
             duration is not None
@@ -178,9 +200,8 @@ class SignedTokenHandler(TokenHandler):
         ):
             duration = max_signed_tokens_ttl
 
-        if duration:
-            if time.time() - created > duration:
-                return None
+        if duration and time.time() - created > duration:
+            raise TokenInvalid("Token has expired")
 
         actor = {"id": decoded["a"], "token": "dstok"}
 

datasette/tracer.py

@@ -1,10 +1,11 @@
 import asyncio
+import json
+import time
+import traceback
 from contextlib import contextmanager
 from contextvars import ContextVar
+
 from markupsafe import escape
-import time
-import json
-import traceback
 
 tracers = {}
 
@@ -27,8 +28,10 @@ def get_task_id():
 @contextmanager
 def trace_child_tasks():
     token = trace_task_id.set(get_task_id())
-    yield
-    trace_task_id.reset(token)
+    try:
+        yield
+    finally:
+        trace_task_id.reset(token)
 
 
 @contextmanager
@@ -130,17 +133,17 @@ class AsgiTracer:
                     "num_traces": len(traces),
                     "traces": traces,
                 }
-                try:
-                    content_type = [
+                content_type = next(
+                    (
                         v.decode("utf8")
                         for k, v in response_headers
                         if k.lower() == b"content-type"
-                    ][0]
-                except IndexError:
-                    content_type = ""
+                    ),
+                    "",
+                )
                 if "text/html" in content_type and b"</body>" in accumulated_body:
                     extra = escape(json.dumps(trace_info, indent=2))
-                    extra_html = f"<pre>{extra}</pre></body>".encode("utf8")
+                    extra_html = f"<pre>{extra}</pre></body>".encode()
                     accumulated_body = accumulated_body.replace(b"</body>", extra_html)
                 elif "json" in content_type and accumulated_body.startswith(b"{"):
                     data = json.loads(accumulated_body.decode("utf8"))

datasette/url_builder.py

@@ -1,6 +1,7 @@
-from .utils import tilde_encode, path_with_format, PrefixedUrlString
 import urllib
 
+from .utils import PrefixedUrlString, path_with_format, tilde_encode
+
 
 class Urls:
     def __init__(self, ds):
@@ -8,8 +9,7 @@ class Urls:
 
     def path(self, path, format=None):
         if not isinstance(path, PrefixedUrlString):
-            if path.startswith("/"):
-                path = path[1:]
+            path = path.removeprefix("/")
             path = self.ds.setting("base_url") + path
         if format is not None:
             path = path_with_format(path=path, format=format)
@@ -56,6 +56,7 @@ class Urls:
         return PrefixedUrlString(path)
 
     def row_blob(self, database, table, row_path, column):
-        return self.table(database, table) + "/{}.blob?_blob_column={}".format(
-            row_path, urllib.parse.quote_plus(column)
+        return (
+            self.table(database, table)
+            + f"/{row_path}.blob?_blob_column={urllib.parse.quote_plus(column)}"
         )

datasette/utils/__init__.py

@@ -1,28 +1,31 @@
 import asyncio
-from contextlib import contextmanager
-import aiofiles
-import click
-from collections import OrderedDict, namedtuple, Counter
+import base64
+import binascii
 import copy
 import dataclasses
-import base64
 import hashlib
 import inspect
 import json
-import markupsafe
-import mergedeep
 import os
 import re
+import secrets
 import shlex
+import shutil
 import tempfile
-import typing
 import time
 import types
-import secrets
-import shutil
-from typing import Iterable, List, Tuple
+import typing
 import urllib
+from collections import Counter, OrderedDict, namedtuple
+from collections.abc import Iterable
+from contextlib import contextmanager
+
+import aiofiles
+import click
+import markupsafe
+import mergedeep
 import yaml
+
 from .shutil_backport import copytree
 from .sqlite import sqlite3, supports_table_xinfo
 
@@ -35,7 +38,7 @@ if typing.TYPE_CHECKING:
 class PaginatedResources:
     """Paginated results from allowed_resources query."""
 
-    resources: List["Resource"]
+    resources: list["Resource"]
     next: str | None  # Keyset token for next page (None if no more results)
     _datasette: typing.Any = dataclasses.field(default=None, repr=False)
     _action: str = dataclasses.field(default=None, repr=False)
@@ -82,22 +85,132 @@ class PaginatedResources:
 
 
 # From https://www.sqlite.org/lang_keywords.html
-reserved_words = set(
-    (
-        "abort action add after all alter analyze and as asc attach autoincrement "
-        "before begin between by cascade case cast check collate column commit "
-        "conflict constraint create cross current_date current_time "
-        "current_timestamp database default deferrable deferred delete desc detach "
-        "distinct drop each else end escape except exclusive exists explain fail "
-        "for foreign from full glob group having if ignore immediate in index "
-        "indexed initially inner insert instead intersect into is isnull join key "
-        "left like limit match natural no not notnull null of offset on or order "
-        "outer plan pragma primary query raise recursive references regexp reindex "
-        "release rename replace restrict right rollback row savepoint select set "
-        "table temp temporary then to transaction trigger union unique update using "
-        "vacuum values view virtual when where with without"
-    ).split()
-)
+reserved_words = {
+    "abort",
+    "action",
+    "add",
+    "after",
+    "all",
+    "alter",
+    "analyze",
+    "and",
+    "as",
+    "asc",
+    "attach",
+    "autoincrement",
+    "before",
+    "begin",
+    "between",
+    "by",
+    "cascade",
+    "case",
+    "cast",
+    "check",
+    "collate",
+    "column",
+    "commit",
+    "conflict",
+    "constraint",
+    "create",
+    "cross",
+    "current_date",
+    "current_time",
+    "current_timestamp",
+    "database",
+    "default",
+    "deferrable",
+    "deferred",
+    "delete",
+    "desc",
+    "detach",
+    "distinct",
+    "drop",
+    "each",
+    "else",
+    "end",
+    "escape",
+    "except",
+    "exclusive",
+    "exists",
+    "explain",
+    "fail",
+    "for",
+    "foreign",
+    "from",
+    "full",
+    "glob",
+    "group",
+    "having",
+    "if",
+    "ignore",
+    "immediate",
+    "in",
+    "index",
+    "indexed",
+    "initially",
+    "inner",
+    "insert",
+    "instead",
+    "intersect",
+    "into",
+    "is",
+    "isnull",
+    "join",
+    "key",
+    "left",
+    "like",
+    "limit",
+    "match",
+    "natural",
+    "no",
+    "not",
+    "notnull",
+    "null",
+    "of",
+    "offset",
+    "on",
+    "or",
+    "order",
+    "outer",
+    "plan",
+    "pragma",
+    "primary",
+    "query",
+    "raise",
+    "recursive",
+    "references",
+    "regexp",
+    "reindex",
+    "release",
+    "rename",
+    "replace",
+    "restrict",
+    "right",
+    "rollback",
+    "row",
+    "savepoint",
+    "select",
+    "set",
+    "table",
+    "temp",
+    "temporary",
+    "then",
+    "to",
+    "transaction",
+    "trigger",
+    "union",
+    "unique",
+    "update",
+    "using",
+    "vacuum",
+    "values",
+    "view",
+    "virtual",
+    "when",
+    "where",
+    "with",
+    "without",
+}
 
 APT_GET_DOCKERFILE_EXTRAS = r"""
 RUN apt-get update && \
@@ -157,7 +270,7 @@ functions_marked_as_documented = []
 
 def documented(fn=None, *, label=None):
     def decorate(fn):
-        fn._datasette_docs_label = label or "internals_utils_{}".format(fn.__name__)
+        fn._datasette_docs_label = label or f"internals_utils_{fn.__name__}"
         functions_marked_as_documented.append(fn)
         return fn
 
@@ -224,24 +337,71 @@ def compound_keys_after_sql(pks, start_index=0):
     return "({})".format("\n  or\n".join(or_clauses))
 
 
+@documented
 class CustomJSONEncoder(json.JSONEncoder):
+    """
+    The CustomJSONEncoder class handles serialization for objects commonly used by Datasette,
+    including SQLite cursors and binary blobs. Datasette uses it internally to serve .json endpoints,
+    and plugins that return JSON can use it to match Datasette's own handling.
+
+    Built-in types (text, numbers, lists, etc) are encoded the same as Python's built-in ``json`` module.
+
+    - ``sqlite3.Row`` becomes a tuple
+    - ``sqlite3.Cursor`` becomes a list
+
+    Binary blobs are encoded as an object, with the actual data base64-encoded,
+    like so: ::
+
+        {
+            "$base64": True,
+            "encoded": ...,
+        }
+
+    Example: https://latest.datasette.io/fixtures/binary_data.json
+    """
+
     def default(self, obj):
         if isinstance(obj, sqlite3.Row):
             return tuple(obj)
         if isinstance(obj, sqlite3.Cursor):
             return list(obj)
         if isinstance(obj, bytes):
-            # Does it encode to utf8?
-            try:
-                return obj.decode("utf8")
-            except UnicodeDecodeError:
-                return {
-                    "$base64": True,
-                    "encoded": base64.b64encode(obj).decode("latin1"),
-                }
+            return {
+                "$base64": True,
+                "encoded": base64.b64encode(obj).decode("latin1"),
+            }
         return json.JSONEncoder.default(self, obj)
 
 
+class WriteJsonValueError(ValueError):
+    pass
+
+
+def decode_write_json_cell(value):
+    if not isinstance(value, dict):
+        return value
+    keys = set(value.keys())
+    if keys == {"$raw"}:
+        return value["$raw"]
+    if keys == {"$base64", "encoded"} and value.get("$base64") is True:
+        encoded = value["encoded"]
+        if not isinstance(encoded, str):
+            raise WriteJsonValueError("$base64 encoded value must be a string")
+        try:
+            return base64.b64decode(encoded, validate=True)
+        except binascii.Error as ex:
+            raise WriteJsonValueError("Invalid $base64 encoded value") from ex
+    return value
+
+
+def decode_write_json_row(row):
+    return {key: decode_write_json_cell(value) for key, value in row.items()}
+
+
+def decode_write_json_rows(rows):
+    return [decode_write_json_row(row) for row in rows]
+
+
 @contextmanager
 def sqlite_timelimit(conn, ms):
     deadline = time.perf_counter() + (ms / 1000)
@@ -312,7 +472,7 @@ disallawed_sql_res = [
     (
         re.compile(f"pragma(?!_({'|'.join(allowed_pragmas)}))"),
         "Statement contained a disallowed PRAGMA. Allowed pragma functions are {}".format(
-            ", ".join("pragma_{}()".format(pragma) for pragma in allowed_pragmas)
+            ", ".join(f"pragma_{pragma}()" for pragma in allowed_pragmas)
         ),
     )
 ]
@@ -410,8 +570,7 @@ def escape_css_string(s):
 def escape_sqlite(s):
     if _boring_keyword_re.match(s) and (s.lower() not in reserved_words):
         return s
-    else:
-        return f"[{s}]"
+    return '"{}"'.format(s.replace('"', '""'))
 
 
 def make_dockerfile(
@@ -487,10 +646,7 @@ CMD {cmd}""".format(
             else ""
         ),
         environment_variables="\n".join(
-            [
-                "ENV {} '{}'".format(key, value)
-                for key, value in environment_variables.items()
-            ]
+            [f"ENV {key} '{value}'" for key, value in environment_variables.items()]
         ),
         install_from=" ".join(install),
         files=" ".join(files),
@@ -589,11 +745,11 @@ def detect_primary_keys(conn, table):
 
 
 def get_outbound_foreign_keys(conn, table):
-    infos = conn.execute(f"PRAGMA foreign_key_list([{table}])").fetchall()
+    infos = conn.execute(f"PRAGMA foreign_key_list({escape_sqlite(table)})").fetchall()
     fks = []
     for info in infos:
         if info is not None:
-            id, seq, table_name, from_, to_, on_update, on_delete, match = info
+            id, seq, table_name, from_, to_, _on_update, _on_delete, _match = info
             fks.append(
                 {
                     "column": from_,
@@ -694,7 +850,7 @@ def detect_json1(conn=None):
     try:
         conn.execute("SELECT json('{}')")
         return True
-    except Exception:
+    except sqlite3.Error:
         return False
     finally:
         if close_conn:
@@ -774,9 +930,7 @@ def is_url(value):
     if not value.startswith("http://") and not value.startswith("https://"):
         return False
     # Any whitespace at all is invalid
-    if whitespace_re.search(value):
-        return False
-    return True
+    return not whitespace_re.search(value)
 
 
 css_class_re = re.compile(r"^[a-zA-Z]+[_a-zA-Z0-9-]*$")
@@ -829,7 +983,9 @@ def module_from_path(path, name):
     mod.__file__ = path
     with open(path, "r") as file:
         code = compile(file.read(), path, "exec", dont_inherit=True)
-    exec(code, mod.__dict__)
+    # Executing the file is the whole point - this is how --plugins-dir loads
+    # plugins and how metadata/config .py files are evaluated
+    exec(code, mod.__dict__)  # noqa: S102
     return mod
 
 
@@ -986,9 +1142,7 @@ def escape_fts(query):
         query += '"'
     bits = _escape_fts_re.split(query)
     bits = [b for b in bits if b and b != '""']
-    return " ".join(
-        '"{}"'.format(bit) if not bit.startswith('"') else bit for bit in bits
-    )
+    return " ".join(f'"{bit}"' if not bit.startswith('"') else bit for bit in bits)
 
 
 class MultiParams:
@@ -1000,7 +1154,7 @@ class MultiParams:
                     data[key], (list, tuple)
                 ), "dictionary data should be a dictionary of key => [list]"
             self._data = data
-        elif isinstance(data, list) or isinstance(data, tuple):
+        elif isinstance(data, (list, tuple)):
             new_data = {}
             for item in data:
                 assert (
@@ -1090,9 +1244,7 @@ def _gather_arguments(fn, kwargs):
     for parameter in parameters:
         if parameter not in kwargs:
             raise TypeError(
-                "{} requires parameters {}, missing: {}".format(
-                    fn, tuple(parameters), set(parameters) - set(kwargs.keys())
-                )
+                f"{fn} requires parameters {tuple(parameters)}, missing: {set(parameters) - set(kwargs.keys())}"
             )
         call_with.append(kwargs[parameter])
     return call_with
@@ -1161,9 +1313,9 @@ def resolve_env_secrets(config, environ):
     """Create copy that recursively replaces {"$env": "NAME"} with values from environ"""
     if isinstance(config, dict):
         if list(config.keys()) == ["$env"]:
-            return environ.get(list(config.values())[0])
+            return environ.get(next(iter(config.values())))
         elif list(config.keys()) == ["$file"]:
-            with open(list(config.values())[0]) as fp:
+            with open(next(iter(config.values()))) as fp:
                 return fp.read()
         else:
             return {
@@ -1241,29 +1393,38 @@ class StartupError(Exception):
     pass
 
 
-_single_line_comment_re = re.compile(r"--.*")
-_multi_line_comment_re = re.compile(r"/\*.*?\*/", re.DOTALL)
-_single_quote_re = re.compile(r"'(?:''|[^'])*'")
-_double_quote_re = re.compile(r'"(?:\"\"|[^"])*"')
+# Comments and string literals, matched in a single pass so that whichever
+# construct starts first "wins" - this ensures a comment marker inside a string
+# literal (or a quote inside a comment) does not confuse the parameter scan.
+_comments_and_strings_re = re.compile(
+    r"""
+    --[^\n]*            # single line comment
+    | /\*.*?(?:\*/|\Z)  # multi line comment, possibly to end-of-input
+    | '(?:''|[^'])*'    # single quoted string ('' escapes a quote)
+    | "(?:""|[^"])*"    # double quoted identifier ("" escapes a quote)
+    | \[(?:[^\]])*\]    # square-bracket quoted identifier
+    | `(?:``|[^`])*`    # backtick quoted identifier
+    """,
+    re.DOTALL | re.VERBOSE,
+)
 _named_param_re = re.compile(r":(\w+)")
 
 
 @documented
-def named_parameters(sql: str) -> List[str]:
+def named_parameters(sql: str) -> list[str]:
     """
     Given a SQL statement, return a list of named parameters that are used in the statement
 
     e.g. for ``select * from foo where id=:id`` this would return ``["id"]``
     """
-    sql = _single_line_comment_re.sub("", sql)
-    sql = _multi_line_comment_re.sub("", sql)
-    sql = _single_quote_re.sub("", sql)
-    sql = _double_quote_re.sub("", sql)
+    # Strip comments and string literals first so that any ":name" sequences
+    # inside them are not mistaken for named parameters
+    sql = _comments_and_strings_re.sub("", sql)
     # Extract parameters from what is left
     return _named_param_re.findall(sql)
 
 
-async def derive_named_parameters(db: "Database", sql: str) -> List[str]:
+async def derive_named_parameters(db: "Database", sql: str) -> list[str]:
     """
     This undocumented but stable method exists for backwards compatibility
     with plugins that were using it before it switched to named_parameters()
@@ -1271,6 +1432,54 @@ async def derive_named_parameters(db: "Database", sql: str) -> List[str]:
     return named_parameters(sql)
 
 
+def parse_size_limit(value, default, maximum, name="_size"):
+    """
+    Parse a page-size parameter using the same semantics as the table
+    view's ?_size=: blank means default, "max" means maximum, integers
+    must be 0 or greater and no larger than maximum. Raises ValueError
+    with a message suitable for a 400 response.
+    """
+    if value in (None, ""):
+        return default
+    if value == "max":
+        return maximum
+    try:
+        size = int(value)
+        if size < 0:
+            raise ValueError
+    except ValueError:
+        raise ValueError(f"{name} must be a positive integer")
+    if size > maximum:
+        raise ValueError(f"{name} must be <= {maximum}")
+    return size
+
+
+UNSTABLE_API_MESSAGE = (
+    "This API is not part of Datasette's stable interface and may change at any time"
+)
+
+
+def error_body(messages, status):
+    """
+    The canonical JSON error body used by every Datasette JSON error response:
+
+        {"ok": False, "error": "...", "errors": ["...", ...], "status": 400}
+
+    "error" is all of the messages joined with "; ", "errors" is the full
+    list, "status" matches the HTTP status code. Callers may add extra
+    context keys to the returned dictionary but must not remove these four.
+    """
+    if isinstance(messages, str):
+        messages = [messages]
+    messages = [str(message) for message in messages]
+    return {
+        "ok": False,
+        "error": "; ".join(messages),
+        "errors": messages,
+        "status": status,
+    }
+
+
 def add_cors_headers(headers):
     headers["Access-Control-Allow-Origin"] = "*"
     headers["Access-Control-Allow-Headers"] = "Authorization, Content-Type"
@@ -1299,7 +1508,7 @@ class TildeEncoder(dict):
         elif b == _space:
             res = "+"
         else:
-            res = "~{:02X}".format(b)
+            res = f"~{b:02X}"
         self[b] = res
         return res
 
@@ -1394,7 +1603,7 @@ def _combine(base: dict, update: dict) -> dict:
     return base
 
 
-def pairs_to_nested_config(pairs: typing.List[typing.Tuple[str, typing.Any]]) -> dict:
+def pairs_to_nested_config(pairs: list[tuple[str, typing.Any]]) -> dict:
     """
     Parse a list of key-value pairs into a nested dictionary.
     """
@@ -1409,7 +1618,7 @@ def make_slot_function(name, datasette, request, **kwargs):
     from datasette.plugins import pm
 
     method = getattr(pm.hook, name, None)
-    assert method is not None, "No hook found for {}".format(name)
+    assert method is not None, f"No hook found for {name}"
 
     async def inner():
         html_bits = []
@@ -1433,7 +1642,7 @@ def prune_empty_dicts(d: dict):
                 d.pop(key, None)
 
 
-def move_plugins_and_allow(source: dict, destination: dict) -> Tuple[dict, dict]:
+def move_plugins_and_allow(source: dict, destination: dict) -> tuple[dict, dict]:
     """
     Move 'plugins' and 'allow' keys from source to destination dictionary. Creates
     hierarchy in destination if needed. After moving, recursively remove any keys
@@ -1544,6 +1753,17 @@ def md5_not_usedforsecurity(s):
 _etag_cache = {}
 
 
+def sha256_file(filepath, chunk_size=4096):
+    hasher = hashlib.sha256()
+    with open(filepath, "rb") as fp:
+        while True:
+            chunk = fp.read(chunk_size)
+            if not chunk:
+                break
+            hasher.update(chunk)
+    return hasher.hexdigest()
+
+
 async def calculate_etag(filepath, chunk_size=4096):
     if filepath in _etag_cache:
         return _etag_cache[filepath]

datasette/utils/actions_sql.py

@@ -21,6 +21,8 @@ The core pattern is:
 - Across levels, child beats parent beats global
 """
 
+import asyncio
+import re
 from typing import TYPE_CHECKING
 
 from datasette.utils.permissions import gather_permission_sql_from_hooks
@@ -250,88 +252,62 @@ async def _build_single_action_sql(
                 ]
             )
 
-    # Continue with the cascading logic
-    query_parts.extend(
-        [
-            "child_lvl AS (",
-            "  SELECT b.parent, b.child,",
-            "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-            "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow,",
-            "         json_group_array(CASE WHEN ar.allow = 0 THEN ar.source_plugin || ': ' || ar.reason END) AS deny_reasons,",
-            "         json_group_array(CASE WHEN ar.allow = 1 THEN ar.source_plugin || ': ' || ar.reason END) AS allow_reasons",
-            "  FROM base b",
-            "  LEFT JOIN all_rules ar ON ar.parent = b.parent AND ar.child = b.child",
-            "  GROUP BY b.parent, b.child",
-            "),",
-            "parent_lvl AS (",
-            "  SELECT b.parent, b.child,",
-            "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-            "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow,",
-            "         json_group_array(CASE WHEN ar.allow = 0 THEN ar.source_plugin || ': ' || ar.reason END) AS deny_reasons,",
-            "         json_group_array(CASE WHEN ar.allow = 1 THEN ar.source_plugin || ': ' || ar.reason END) AS allow_reasons",
-            "  FROM base b",
-            "  LEFT JOIN all_rules ar ON ar.parent = b.parent AND ar.child IS NULL",
-            "  GROUP BY b.parent, b.child",
-            "),",
-            "global_lvl AS (",
-            "  SELECT b.parent, b.child,",
-            "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-            "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow,",
-            "         json_group_array(CASE WHEN ar.allow = 0 THEN ar.source_plugin || ': ' || ar.reason END) AS deny_reasons,",
-            "         json_group_array(CASE WHEN ar.allow = 1 THEN ar.source_plugin || ': ' || ar.reason END) AS allow_reasons",
-            "  FROM base b",
-            "  LEFT JOIN all_rules ar ON ar.parent IS NULL AND ar.child IS NULL",
-            "  GROUP BY b.parent, b.child",
-            "),",
+    # Continue with the cascading logic.
+    # Aggregate the RULES by cascade level (small), rather than grouping
+    # base x rules (which scales with the number of resources).
+    def _agg(select_key, where, group_by):
+        parts = [
+            f"  SELECT {select_key}",
+            "         MAX(CASE WHEN allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
+            "         MAX(CASE WHEN allow = 1 THEN 1 ELSE 0 END) AS any_allow,",
+            "         json_group_array(CASE WHEN allow = 0 THEN source_plugin || ': ' || reason END) AS deny_reasons,",
+            "         json_group_array(CASE WHEN allow = 1 THEN source_plugin || ': ' || reason END) AS allow_reasons",
+            f"  FROM all_rules WHERE {where}",
         ]
+        if group_by:
+            parts.append(f"  GROUP BY {group_by}")
+        return parts
+
+    query_parts.extend(
+        ["child_agg AS ("]
+        + _agg(
+            "parent, child,",
+            "parent IS NOT NULL AND child IS NOT NULL",
+            "parent, child",
+        )
+        + ["),", "parent_agg AS ("]
+        + _agg("parent,", "parent IS NOT NULL AND child IS NULL", "parent")
+        + ["),", "global_agg AS ("]
+        + _agg("", "parent IS NULL AND child IS NULL", None)
+        + ["),"]
     )
 
     # Add anonymous decision logic if needed
     if include_is_private:
-        query_parts.extend(
-            [
-                "anon_child_lvl AS (",
-                "  SELECT b.parent, b.child,",
-                "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-                "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow",
-                "  FROM base b",
-                "  LEFT JOIN anon_rules ar ON ar.parent = b.parent AND ar.child = b.child",
-                "  GROUP BY b.parent, b.child",
-                "),",
-                "anon_parent_lvl AS (",
-                "  SELECT b.parent, b.child,",
-                "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-                "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow",
-                "  FROM base b",
-                "  LEFT JOIN anon_rules ar ON ar.parent = b.parent AND ar.child IS NULL",
-                "  GROUP BY b.parent, b.child",
-                "),",
-                "anon_global_lvl AS (",
-                "  SELECT b.parent, b.child,",
-                "         MAX(CASE WHEN ar.allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
-                "         MAX(CASE WHEN ar.allow = 1 THEN 1 ELSE 0 END) AS any_allow",
-                "  FROM base b",
-                "  LEFT JOIN anon_rules ar ON ar.parent IS NULL AND ar.child IS NULL",
-                "  GROUP BY b.parent, b.child",
-                "),",
-                "anon_decisions AS (",
-                "  SELECT",
-                "    b.parent, b.child,",
-                "    CASE",
-                "      WHEN acl.any_deny = 1 THEN 0",
-                "      WHEN acl.any_allow = 1 THEN 1",
-                "      WHEN apl.any_deny = 1 THEN 0",
-                "      WHEN apl.any_allow = 1 THEN 1",
-                "      WHEN agl.any_deny = 1 THEN 0",
-                "      WHEN agl.any_allow = 1 THEN 1",
-                "      ELSE 0",
-                "    END AS anon_is_allowed",
-                "  FROM base b",
-                "  JOIN anon_child_lvl acl ON b.parent = acl.parent AND (b.child = acl.child OR (b.child IS NULL AND acl.child IS NULL))",
-                "  JOIN anon_parent_lvl apl ON b.parent = apl.parent AND (b.child = apl.child OR (b.child IS NULL AND apl.child IS NULL))",
-                "  JOIN anon_global_lvl agl ON b.parent = agl.parent AND (b.child = agl.child OR (b.child IS NULL AND agl.child IS NULL))",
-                "),",
+
+        def _anon_agg(select_key, where, group_by):
+            parts = [
+                f"  SELECT {select_key}",
+                "         MAX(CASE WHEN allow = 0 THEN 1 ELSE 0 END) AS any_deny,",
+                "         MAX(CASE WHEN allow = 1 THEN 1 ELSE 0 END) AS any_allow",
+                f"  FROM anon_rules WHERE {where}",
             ]
+            if group_by:
+                parts.append(f"  GROUP BY {group_by}")
+            return parts
+
+        query_parts.extend(
+            ["anon_child_agg AS ("]
+            + _anon_agg(
+                "parent, child,",
+                "parent IS NOT NULL AND child IS NOT NULL",
+                "parent, child",
+            )
+            + ["),", "anon_parent_agg AS ("]
+            + _anon_agg("parent,", "parent IS NOT NULL AND child IS NULL", "parent")
+            + ["),", "anon_global_agg AS ("]
+            + _anon_agg("", "parent IS NULL AND child IS NULL", None)
+            + ["),"]
         )
 
     # Final decisions
@@ -340,31 +316,28 @@ async def _build_single_action_sql(
             "decisions AS (",
             "  SELECT",
             "    b.parent, b.child,",
-            "    -- Cascading permission logic: child → parent → global, DENY beats ALLOW at each level",
+            "    -- Cascading permission logic: child -> parent -> global, DENY beats ALLOW at each level",
             "    -- Priority order:",
-            "    --   1. Child-level deny (most specific, blocks access)",
-            "    --   2. Child-level allow (most specific, grants access)",
-            "    --   3. Parent-level deny (intermediate, blocks access)",
-            "    --   4. Parent-level allow (intermediate, grants access)",
-            "    --   5. Global-level deny (least specific, blocks access)",
-            "    --   6. Global-level allow (least specific, grants access)",
+            "    --   1. Child-level deny  2. Child-level allow",
+            "    --   3. Parent-level deny 4. Parent-level allow",
+            "    --   5. Global-level deny 6. Global-level allow",
             "    --   7. Default deny (no rules match)",
             "    CASE",
-            "      WHEN cl.any_deny = 1 THEN 0",
-            "      WHEN cl.any_allow = 1 THEN 1",
-            "      WHEN pl.any_deny = 1 THEN 0",
-            "      WHEN pl.any_allow = 1 THEN 1",
-            "      WHEN gl.any_deny = 1 THEN 0",
-            "      WHEN gl.any_allow = 1 THEN 1",
+            "      WHEN ca.any_deny = 1 THEN 0",
+            "      WHEN ca.any_allow = 1 THEN 1",
+            "      WHEN pa.any_deny = 1 THEN 0",
+            "      WHEN pa.any_allow = 1 THEN 1",
+            "      WHEN ga.any_deny = 1 THEN 0",
+            "      WHEN ga.any_allow = 1 THEN 1",
             "      ELSE 0",
             "    END AS is_allowed,",
             "    CASE",
-            "      WHEN cl.any_deny = 1 THEN cl.deny_reasons",
-            "      WHEN cl.any_allow = 1 THEN cl.allow_reasons",
-            "      WHEN pl.any_deny = 1 THEN pl.deny_reasons",
-            "      WHEN pl.any_allow = 1 THEN pl.allow_reasons",
-            "      WHEN gl.any_deny = 1 THEN gl.deny_reasons",
-            "      WHEN gl.any_allow = 1 THEN gl.allow_reasons",
+            "      WHEN ca.any_deny = 1 THEN ca.deny_reasons",
+            "      WHEN ca.any_allow = 1 THEN ca.allow_reasons",
+            "      WHEN pa.any_deny = 1 THEN pa.deny_reasons",
+            "      WHEN pa.any_allow = 1 THEN pa.allow_reasons",
+            "      WHEN ga.any_deny = 1 THEN ga.deny_reasons",
+            "      WHEN ga.any_allow = 1 THEN ga.allow_reasons",
             "      ELSE '[]'",
             "    END AS reason",
         ]
@@ -372,21 +345,34 @@ async def _build_single_action_sql(
 
     if include_is_private:
         query_parts.append(
-            "    , CASE WHEN ad.anon_is_allowed = 0 THEN 1 ELSE 0 END AS is_private"
+            "    , CASE WHEN ("
+            "CASE"
+            " WHEN aca.any_deny = 1 THEN 0"
+            " WHEN aca.any_allow = 1 THEN 1"
+            " WHEN apa.any_deny = 1 THEN 0"
+            " WHEN apa.any_allow = 1 THEN 1"
+            " WHEN aga.any_deny = 1 THEN 0"
+            " WHEN aga.any_allow = 1 THEN 1"
+            " ELSE 0 END"
+            ") = 0 THEN 1 ELSE 0 END AS is_private"
         )
 
     query_parts.extend(
         [
             "  FROM base b",
-            "  JOIN child_lvl cl ON b.parent = cl.parent AND (b.child = cl.child OR (b.child IS NULL AND cl.child IS NULL))",
-            "  JOIN parent_lvl pl ON b.parent = pl.parent AND (b.child = pl.child OR (b.child IS NULL AND pl.child IS NULL))",
-            "  JOIN global_lvl gl ON b.parent = gl.parent AND (b.child = gl.child OR (b.child IS NULL AND gl.child IS NULL))",
+            "  LEFT JOIN child_agg ca ON ca.parent = b.parent AND ca.child = b.child",
+            "  LEFT JOIN parent_agg pa ON pa.parent = b.parent",
+            "  CROSS JOIN global_agg ga",
         ]
     )
 
     if include_is_private:
-        query_parts.append(
-            "  JOIN anon_decisions ad ON b.parent = ad.parent AND (b.child = ad.child OR (b.child IS NULL AND ad.child IS NULL))"
+        query_parts.extend(
+            [
+                "  LEFT JOIN anon_child_agg aca ON aca.parent = b.parent AND aca.child = b.child",
+                "  LEFT JOIN anon_parent_agg apa ON apa.parent = b.parent",
+                "  CROSS JOIN anon_global_agg aga",
+            ]
         )
 
     query_parts.append(")")
@@ -398,8 +384,28 @@ async def _build_single_action_sql(
         restriction_intersect = "\nINTERSECT\n".join(
             f"SELECT * FROM ({sql})" for sql in restriction_sqls
         )
+        # Decompose by NULL-pattern so the final filter can use pure-equality
+        # EXISTS lookups (satisfiable via automatic indexes) instead of a
+        # correlated OR-scan over the whole list.
         query_parts.extend(
-            [",", "restriction_list AS (", f"  {restriction_intersect}", ")"]
+            [
+                ",",
+                "restriction_list AS (",
+                f"  {restriction_intersect}",
+                "),",
+                "restriction_exact AS (",
+                "  SELECT parent, child FROM restriction_list WHERE parent IS NOT NULL AND child IS NOT NULL",
+                "),",
+                "restriction_parent_any AS (",
+                "  SELECT DISTINCT parent FROM restriction_list WHERE parent IS NOT NULL AND child IS NULL",
+                "),",
+                "restriction_child_any AS (",
+                "  SELECT DISTINCT child FROM restriction_list WHERE parent IS NULL AND child IS NOT NULL",
+                "),",
+                "restriction_all AS (",
+                "  SELECT 1 AS matched FROM restriction_list WHERE parent IS NULL AND child IS NULL LIMIT 1",
+                ")",
+            ]
         )
 
     # Final SELECT
@@ -414,10 +420,11 @@ async def _build_single_action_sql(
     # Add restriction filter if there are restrictions
     if restriction_sqls:
         query_parts.append("""
-  AND EXISTS (
-    SELECT 1 FROM restriction_list r
-    WHERE (r.parent = decisions.parent OR r.parent IS NULL)
-      AND (r.child = decisions.child OR r.child IS NULL)
+  AND (
+    EXISTS (SELECT 1 FROM restriction_all)
+    OR EXISTS (SELECT 1 FROM restriction_parent_any r WHERE r.parent = decisions.parent)
+    OR EXISTS (SELECT 1 FROM restriction_child_any r WHERE r.child = decisions.child)
+    OR EXISTS (SELECT 1 FROM restriction_exact r WHERE r.parent = decisions.parent AND r.child = decisions.child)
   )""")
 
     # Add parent filter if specified
@@ -495,6 +502,153 @@ async def build_permission_rules_sql(
     return rules_union, all_params, restriction_sqls
 
 
+async def check_permissions_for_actions(
+    *,
+    datasette: "Datasette",
+    actor: dict | None,
+    actions: list[str],
+    parent: str | None,
+    child: str | None,
+) -> dict[str, bool]:
+    """
+    Check several actions for one actor and resource in a single query.
+
+    Args:
+        datasette: The Datasette instance
+        actor: The actor dict (or None)
+        actions: List of action names to check
+        parent: The parent resource identifier (e.g., database name, or None)
+        child: The child resource identifier (e.g., table name, or None)
+
+    Returns:
+        Dict mapping each action name to True (allowed) or False (denied)
+
+    Each action contributes its own tagged block of permission rules
+    (gathered from the permission_resources_sql hook, with parameters
+    namespaced per action to avoid collisions) plus an optional
+    restriction allowlist CTE. One internal database query resolves
+    the winning rule per action using the same specificity-then-deny
+    ordering as the rest of the permission system.
+
+    Note: this resolves each action independently - also_requires
+    dependencies are handled by the caller (Datasette.allowed_many).
+    """
+    from datasette.utils.permissions import SKIP_PERMISSION_CHECKS
+
+    for action in actions:
+        if not datasette.actions.get(action):
+            raise ValueError(f"Unknown action: {action}")
+
+    # Dedupe while preserving order
+    unique_actions = list(dict.fromkeys(actions))
+    if not unique_actions:
+        return {}
+
+    # Gather hook results for each action concurrently - hooks within a
+    # single action still run sequentially, preserving existing semantics
+    gathered = await asyncio.gather(
+        *(
+            gather_permission_sql_from_hooks(
+                datasette=datasette, actor=actor, action=action
+            )
+            for action in unique_actions
+        )
+    )
+
+    if any(result is SKIP_PERMISSION_CHECKS for result in gathered):
+        return {action: True for action in unique_actions}
+
+    params = {"_check_parent": parent, "_check_child": child}
+    ctes = []
+    result_rows = []
+    verdicts = {}
+
+    for i, (action, permission_sqls) in enumerate(zip(unique_actions, gathered)):
+        prefix = f"a{i}_"
+        rule_parts = []
+        restriction_parts = []
+
+        for permission_sql in permission_sqls:
+            sql = permission_sql.sql
+            restriction_sql = permission_sql.restriction_sql
+            # Namespace this block's params so identical names used for
+            # different actions cannot collide
+            for key in permission_sql.params or {}:
+                new_key = prefix + key
+                params[new_key] = permission_sql.params[key]
+                pattern = re.compile(":" + re.escape(key) + r"(?![A-Za-z0-9_])")
+                if sql:
+                    sql = pattern.sub(":" + new_key, sql)
+                if restriction_sql:
+                    restriction_sql = pattern.sub(":" + new_key, restriction_sql)
+
+            if restriction_sql:
+                restriction_parts.append(restriction_sql)
+
+            # Skip plugins that only provide restriction_sql (no permission rules)
+            if sql is None:
+                continue
+            rule_parts.append(
+                f"SELECT parent, child, allow, reason, '{permission_sql.source}' AS source_plugin FROM (\n{sql}\n)"
+            )
+
+        if not rule_parts:
+            # No rules from any plugin - default deny. Restrictions can
+            # only restrict, never grant, so no SQL is needed at all
+            verdicts[action] = False
+            continue
+        ctes.append(f"a{i}_rules AS (\n" + "\nUNION ALL\n".join(rule_parts) + "\n)")
+
+        # Winning rule for this action: most specific depth first, then
+        # deny-beats-allow, then source_plugin as a stable tie-break
+        verdict_sql = f"""COALESCE((
+  SELECT allow FROM (
+    SELECT allow, source_plugin,
+      CASE
+        WHEN child IS NOT NULL THEN 2
+        WHEN parent IS NOT NULL THEN 1
+        ELSE 0
+      END AS depth
+    FROM a{i}_rules
+    WHERE (parent IS NULL OR parent = :_check_parent)
+      AND (child IS NULL OR child = :_check_child)
+    ORDER BY
+      depth DESC,
+      CASE WHEN allow = 0 THEN 0 ELSE 1 END,
+      source_plugin
+    LIMIT 1
+  )
+), 0)"""
+
+        if restriction_parts:
+            # Database-level restrictions (parent, NULL) match all children
+            restriction_intersect = "\nINTERSECT\n".join(
+                f"SELECT * FROM ({sql})" for sql in restriction_parts
+            )
+            ctes.append(f"a{i}_restriction AS (\n{restriction_intersect}\n)")
+            verdict_sql = f"""({verdict_sql}) AND EXISTS (
+  SELECT 1 FROM a{i}_restriction r
+  WHERE (r.parent = :_check_parent OR r.parent IS NULL)
+    AND (r.child = :_check_child OR r.child IS NULL)
+)"""
+
+        result_rows.append(f"({i}, ({verdict_sql}))")
+
+    if result_rows:
+        ctes.append(
+            "results(action_idx, is_allowed) AS (VALUES\n"
+            + ",\n".join(result_rows)
+            + "\n)"
+        )
+        query = (
+            "WITH\n" + ",\n".join(ctes) + "\nSELECT action_idx, is_allowed FROM results"
+        )
+        result = await datasette.get_internal_database().execute(query, params)
+        for row in result.rows:
+            verdicts[unique_actions[row[0]]] = bool(row[1])
+    return verdicts
+
+
 async def check_permission_for_resource(
     *,
     datasette: "Datasette",
@@ -515,77 +669,248 @@ async def check_permission_for_resource(
 
     Returns:
         True if the actor is allowed, False otherwise
-
-    This builds the cascading permission query and checks if the specific
-    resource is in the allowed set.
     """
-    rules_union, all_params, restriction_sqls = await build_permission_rules_sql(
-        datasette, actor, action
+    results = await check_permissions_for_actions(
+        datasette=datasette,
+        actor=actor,
+        actions=[action],
+        parent=parent,
+        child=child,
+    )
+    return results[action]
+
+
+async def explain_permission_for_resource(
+    *,
+    datasette: "Datasette",
+    actor: dict | None,
+    action: str,
+    parent: str | None,
+    child: str | None,
+) -> dict:
+    """Explain a permission decision for one action and resource.
+
+    This is intended for Datasette's permission debugging tools. It uses the
+    same ``permission_resources_sql`` hook results and the same resolution
+    rules as :func:`check_permissions_for_actions`, but also returns the
+    matching rules, actor restriction results and ``also_requires`` chain.
+
+    The returned dictionary is part of Datasette's unstable debugging API.
+    """
+
+    action_obj = datasette.actions.get(action)
+    if action_obj is None:
+        raise ValueError(f"Unknown action: {action}")
+
+    explanation = await _explain_single_action(
+        datasette=datasette,
+        actor=actor,
+        action=action,
+        parent=parent,
+        child=child,
     )
 
-    # If no rules (empty SQL), default deny
-    if not rules_union:
-        return False
-
-    # Add parameters for the resource we're checking
-    all_params["_check_parent"] = parent
-    all_params["_check_child"] = child
-
-    # If there are restriction filters, check if the resource passes them first
-    if restriction_sqls:
-        # Check if resource is in restriction allowlist
-        # Database-level restrictions (parent, NULL) should match all children (parent, *)
-        # Wrap each restriction_sql in a subquery to avoid operator precedence issues
-        restriction_check = "\nINTERSECT\n".join(
-            f"SELECT * FROM ({sql})" for sql in restriction_sqls
+    required_actions = []
+    if action_obj.also_requires:
+        required = await explain_permission_for_resource(
+            datasette=datasette,
+            actor=actor,
+            action=action_obj.also_requires,
+            parent=parent,
+            child=child,
         )
-        restriction_query = f"""
-WITH restriction_list AS (
-    {restriction_check}
-)
-SELECT EXISTS (
-    SELECT 1 FROM restriction_list
-    WHERE (parent = :_check_parent OR parent IS NULL)
-      AND (child = :_check_child OR child IS NULL)
-) AS in_allowlist
-"""
-        result = await datasette.get_internal_database().execute(
-            restriction_query, all_params
+        required_actions.append(required)
+
+    explanation["required_actions"] = required_actions
+    explanation["allowed"] = bool(
+        explanation["rule_allowed"]
+        and explanation["restriction_allowed"]
+        and all(required["allowed"] for required in required_actions)
+    )
+    explanation["summary"] = _permission_explanation_summary(explanation)
+    return explanation
+
+
+async def _explain_single_action(
+    *,
+    datasette: "Datasette",
+    actor: dict | None,
+    action: str,
+    parent: str | None,
+    child: str | None,
+) -> dict:
+    """Return matching rules and restrictions for a single action."""
+    from datasette.utils.permissions import SKIP_PERMISSION_CHECKS
+
+    permission_sqls = await gather_permission_sql_from_hooks(
+        datasette=datasette,
+        actor=actor,
+        action=action,
+    )
+
+    if permission_sqls is SKIP_PERMISSION_CHECKS:
+        return {
+            "action": action,
+            "rule_allowed": True,
+            "restriction_allowed": True,
+            "winning_scope": "global",
+            "matched_rules": [
+                {
+                    "scope": "global",
+                    "effect": "allow",
+                    "source": "skip_permission_checks",
+                    "reason": "Permission checks were explicitly skipped",
+                    "decisive": True,
+                    "ignored_because": None,
+                }
+            ],
+            "restrictions": [],
+        }
+
+    db = datasette.get_internal_database()
+    matched_rules = []
+    restrictions = []
+
+    for permission_sql in permission_sqls:
+        params = dict(permission_sql.params or {})
+        parent_param = _unused_parameter_name(params, "_explain_parent")
+        params[parent_param] = parent
+        child_param = _unused_parameter_name(params, "_explain_child")
+        params[child_param] = child
+
+        if permission_sql.sql:
+            rows = await db.execute(
+                f"""
+                SELECT parent, child, allow, reason
+                FROM ({permission_sql.sql}) AS permission_rules
+                WHERE (parent IS NULL OR parent = :{parent_param})
+                  AND (child IS NULL OR child = :{child_param})
+                """,
+                params,
+            )
+            for row in rows:
+                specificity = (
+                    2
+                    if row["child"] is not None
+                    else 1 if row["parent"] is not None else 0
+                )
+                matched_rules.append(
+                    {
+                        "scope": ("resource", "parent", "global")[2 - specificity],
+                        "effect": "allow" if row["allow"] else "deny",
+                        "source": permission_sql.source,
+                        "reason": row["reason"],
+                        "_specificity": specificity,
+                    }
+                )
+
+        if permission_sql.restriction_sql:
+            restriction_row = (
+                await db.execute(
+                    f"""
+                    SELECT EXISTS(
+                        SELECT 1 FROM ({permission_sql.restriction_sql}) AS restriction_rules
+                        WHERE (parent IS NULL OR parent = :{parent_param})
+                          AND (child IS NULL OR child = :{child_param})
+                    ) AS resource_is_in_allowlist
+                    """,
+                    params,
+                )
+            ).first()
+            restriction_allowed = bool(restriction_row[0])
+            restrictions.append(
+                {
+                    "source": permission_sql.source,
+                    "allowed": restriction_allowed,
+                    "reason": params.get("deny")
+                    or (
+                        "Resource is included in this restriction allowlist"
+                        if restriction_allowed
+                        else "Resource is not included in this restriction allowlist"
+                    ),
+                }
+            )
+
+    matched_rules.sort(
+        key=lambda rule: (
+            -rule["_specificity"],
+            0 if rule["effect"] == "deny" else 1,
+            rule["source"] or "",
+            rule["reason"] or "",
         )
-        if result.rows and not result.rows[0][0]:
-            # Resource not in restriction allowlist - deny
-            return False
+    )
 
-    query = f"""
-WITH
-all_rules AS (
-  {rules_union}
-),
-matched_rules AS (
-  SELECT ar.*,
-    CASE
-      WHEN ar.child IS NOT NULL THEN 2  -- child-level (most specific)
-      WHEN ar.parent IS NOT NULL THEN 1  -- parent-level
-      ELSE 0                             -- root/global
-    END AS depth
-  FROM all_rules ar
-  WHERE (ar.parent IS NULL OR ar.parent = :_check_parent)
-    AND (ar.child IS NULL OR ar.child = :_check_child)
-),
-winner AS (
-  SELECT *
-  FROM matched_rules
-  ORDER BY
-    depth DESC,                          -- specificity first (higher depth wins)
-    CASE WHEN allow=0 THEN 0 ELSE 1 END, -- then deny over allow
-    source_plugin                        -- stable tie-break
-  LIMIT 1
-)
-SELECT COALESCE((SELECT allow FROM winner), 0) AS is_allowed
-"""
+    if matched_rules:
+        winning_specificity = matched_rules[0]["_specificity"]
+        winning_rules = [
+            rule
+            for rule in matched_rules
+            if rule["_specificity"] == winning_specificity
+        ]
+        rule_allowed = not any(rule["effect"] == "deny" for rule in winning_rules)
+        winning_scope = winning_rules[0]["scope"]
+    else:
+        winning_specificity = None
+        rule_allowed = False
+        winning_scope = None
 
-    # Execute the query against the internal database
-    result = await datasette.get_internal_database().execute(query, all_params)
-    if result.rows:
-        return bool(result.rows[0][0])
-    return False
+    for rule in matched_rules:
+        specificity = rule.pop("_specificity")
+        if specificity != winning_specificity:
+            rule["decisive"] = False
+            rule["ignored_because"] = "A more specific rule matched"
+        elif not rule_allowed and rule["effect"] == "allow":
+            rule["decisive"] = False
+            rule["ignored_because"] = "A deny rule matched at the same scope"
+        else:
+            rule["decisive"] = True
+            rule["ignored_because"] = None
+
+    return {
+        "action": action,
+        "rule_allowed": rule_allowed,
+        "restriction_allowed": all(
+            restriction["allowed"] for restriction in restrictions
+        ),
+        "winning_scope": winning_scope,
+        "matched_rules": matched_rules,
+        "restrictions": restrictions,
+    }
+
+
+def _unused_parameter_name(params: dict, preferred: str) -> str:
+    """Return a SQL parameter name that is not already in ``params``."""
+    candidate = preferred
+    suffix = 2
+    while candidate in params:
+        candidate = f"{preferred}_{suffix}"
+        suffix += 1
+    return candidate
+
+
+def _permission_explanation_summary(explanation: dict) -> str:
+    denied_requirement = next(
+        (
+            required
+            for required in explanation["required_actions"]
+            if not required["allowed"]
+        ),
+        None,
+    )
+    if denied_requirement:
+        return (
+            f"Denied because {explanation['action']} also requires "
+            f"{denied_requirement['action']}, which was denied."
+        )
+    if not explanation["matched_rules"]:
+        return "Denied because no permission rule matched this actor and resource."
+    if not explanation["rule_allowed"]:
+        return (
+            f"Denied by a {explanation['winning_scope']}-level rule. "
+            "Deny rules take precedence over allow rules at the same scope."
+        )
+    if not explanation["restriction_allowed"]:
+        return (
+            "Denied because the resource is not included in the actor's restrictions."
+        )
+    return f"Allowed by the matching {explanation['winning_scope']}-level rule."

datasette/utils/asgi.py

@@ -1,28 +1,29 @@
 import json
-from typing import Optional
-from datasette.utils import MultiParams, calculate_etag
+import re
+from http.cookies import Morsel, SimpleCookie
+from mimetypes import guess_type
+from pathlib import Path
+from urllib.parse import parse_qs, parse_qsl, urlunparse
+
+import aiofiles
+import aiofiles.os
+
+from datasette.utils import MultiParams, calculate_etag, error_body, sha256_file
 from datasette.utils.multipart import (
-    parse_form_data,
-    MultipartParseError,
-    FormData,
-    DEFAULT_MAX_FILE_SIZE,
-    DEFAULT_MAX_REQUEST_SIZE,
-    DEFAULT_MAX_FIELDS,
-    DEFAULT_MAX_FILES,
-    DEFAULT_MAX_PARTS,
     DEFAULT_MAX_FIELD_SIZE,
+    DEFAULT_MAX_FIELDS,
+    DEFAULT_MAX_FILE_SIZE,
+    DEFAULT_MAX_FILES,
     DEFAULT_MAX_MEMORY_FILE_SIZE,
     DEFAULT_MAX_PART_HEADER_BYTES,
     DEFAULT_MAX_PART_HEADER_LINES,
+    DEFAULT_MAX_PARTS,
+    DEFAULT_MAX_REQUEST_SIZE,
     DEFAULT_MIN_FREE_DISK_BYTES,
+    FormData,
+    MultipartParseError,
+    parse_form_data,
 )
-from mimetypes import guess_type
-from urllib.parse import parse_qs, urlunparse, parse_qsl
-from pathlib import Path
-from http.cookies import SimpleCookie, Morsel
-import aiofiles
-import aiofiles.os
-import re
 
 # Workaround for adding samesite support to pre 3.8 python
 Morsel._reserved["samesite"] = "SameSite"
@@ -67,16 +68,28 @@ class BadRequest(Base400):
     status = 400
 
 
+class PayloadTooLarge(Base400):
+    status = 413
+
+
 SAMESITE_VALUES = ("strict", "lax", "none")
 
+# Bodies read fully into memory (post_body/post_vars/json) are capped at this
+# size unless the max_post_body_bytes setting says otherwise. Kept deliberately
+# far below multipart's DEFAULT_MAX_REQUEST_SIZE: that parser streams to disk,
+# while these bodies are held in RAM and json.loads() can multiply their
+# footprint several times over.
+DEFAULT_MAX_POST_BODY_BYTES = 2 * 1024 * 1024  # 2MB
+
 
 class Request:
-    def __init__(self, scope, receive):
+    def __init__(self, scope, receive, max_post_body_bytes=DEFAULT_MAX_POST_BODY_BYTES):
         self.scope = scope
         self.receive = receive
+        self.max_post_body_bytes = max_post_body_bytes
 
     def __repr__(self):
-        return '<asgi.Request method="{}" url="{}">'.format(self.method, self.url)
+        return f'<asgi.Request method="{self.method}" url="{self.url}">'
 
     @property
     def method(self):
@@ -141,20 +154,52 @@ class Request:
     def actor(self):
         return self.scope.get("actor", None)
 
-    async def post_body(self):
-        body = b""
+    async def post_body(self, max_bytes=None):
+        """
+        Read the request body fully into memory.
+
+        The body is capped at max_bytes - or self.max_post_body_bytes
+        (default 2MB, set from the max_post_body_bytes setting for requests
+        created by Datasette) if max_bytes is not provided. Pass max_bytes=0
+        to disable the limit. Raises PayloadTooLarge (HTTP 413) if exceeded -
+        oversized bodies are rejected as soon as the limit is passed, without
+        buffering the rest.
+        """
+        if max_bytes is None:
+            max_bytes = self.max_post_body_bytes
+        too_large = PayloadTooLarge(
+            f"Request body exceeded maximum size of {max_bytes} bytes"
+        )
+        if max_bytes:
+            # Reject early if the client declares an oversized body
+            try:
+                if int(self.headers.get("content-length", "")) > max_bytes:
+                    raise too_large
+            except ValueError:
+                # Missing or malformed - the streaming check below still applies
+                pass
+        chunks = []
+        received = 0
         more_body = True
         while more_body:
             message = await self.receive()
             assert message["type"] == "http.request", message
-            body += message.get("body", b"")
+            chunk = message.get("body", b"")
+            received += len(chunk)
+            if max_bytes and received > max_bytes:
+                raise too_large
+            chunks.append(chunk)
             more_body = message.get("more_body", False)
-        return body
+        return b"".join(chunks)
 
     async def post_vars(self):
         body = await self.post_body()
         return dict(parse_qsl(body.decode("utf-8"), keep_blank_values=True))
 
+    async def json(self):
+        body = await self.post_body()
+        return json.loads(body)
+
     async def form(
         self,
         files: bool = False,
@@ -162,7 +207,7 @@ class Request:
         max_request_size: int = DEFAULT_MAX_REQUEST_SIZE,
         max_fields: int = DEFAULT_MAX_FIELDS,
         max_files: int = DEFAULT_MAX_FILES,
-        max_parts: Optional[int] = DEFAULT_MAX_PARTS,
+        max_parts: int | None = DEFAULT_MAX_PARTS,
         max_field_size: int = DEFAULT_MAX_FIELD_SIZE,
         max_memory_file_size: int = DEFAULT_MAX_MEMORY_FILE_SIZE,
         max_part_header_bytes: int = DEFAULT_MAX_PART_HEADER_BYTES,
@@ -330,9 +375,11 @@ async def asgi_send_html(send, html, status=200, headers=None):
 
 
 async def asgi_send_redirect(send, location, status=302):
-    # Prevent open redirect vulnerability: strip multiple leading slashes
-    # //example.com would be interpreted as a protocol-relative URL (e.g., https://example.com/)
-    location = re.sub(r"^/+", "/", location)
+    # Prevent open redirect vulnerability: collapse leading slashes and
+    # backslashes down to a single slash. //example.com is a protocol-relative
+    # URL, and browsers normalise backslashes to slashes so /\example.com would
+    # be treated as //example.com - https://github.com/simonw/datasette/issues/2680
+    location = re.sub(r"^[/\\]+", "/", location)
     await asgi_send(
         send,
         "",
@@ -391,6 +438,9 @@ async def asgi_send_file(
             )
 
 
+HASHED_STATIC_CACHE_CONTROL = "max-age=31536000, immutable, public"
+
+
 def asgi_static(root_path, chunk_size=4096, headers=None, content_type=None):
     root_path = Path(root_path)
     static_headers = {}
@@ -417,11 +467,17 @@ def asgi_static(root_path, chunk_size=4096, headers=None, content_type=None):
             return
         try:
             # Calculate ETag for filepath
+            hash_value = request.args.get("_hash")
+            if (
+                hash_value
+                and hash_value == sha256_file(full_path, chunk_size=chunk_size)[:12]
+            ):
+                headers["Cache-Control"] = HASHED_STATIC_CACHE_CONTROL
             etag = await calculate_etag(full_path, chunk_size=chunk_size)
             headers["ETag"] = etag
             if_none_match = request.headers.get("if-none-match")
             if if_none_match and if_none_match == etag:
-                return await asgi_send(send, "", 304)
+                return await asgi_send(send, "", 304, headers=headers)
             await asgi_send_file(
                 send, full_path, chunk_size=chunk_size, headers=headers
             )
@@ -474,9 +530,9 @@ class Response:
         httponly=False,
         samesite="lax",
     ):
-        assert samesite in SAMESITE_VALUES, "samesite should be one of {}".format(
-            SAMESITE_VALUES
-        )
+        assert (
+            samesite in SAMESITE_VALUES
+        ), f"samesite should be one of {SAMESITE_VALUES}"
         cookie = SimpleCookie()
         cookie[key] = value
         for prop_name, prop_value in (
@@ -520,6 +576,18 @@ class Response:
             content_type="application/json; charset=utf-8",
         )
 
+    @classmethod
+    def error(cls, messages, status=400, headers=None):
+        """
+        A JSON error response using Datasette's standard error format.
+
+        messages can be a single string or a list of strings. For errors
+        that should content-negotiate between JSON and HTML, raise
+        Forbidden, NotFound, BadRequest or DatasetteError instead and let
+        Datasette's error handling hooks build the response.
+        """
+        return cls.json(error_body(messages, status), status=status, headers=headers)
+
     @classmethod
     def redirect(cls, path, status=302, headers=None):
         headers = headers or {}

datasette/utils/baseconv.py

@@ -13,7 +13,7 @@ Originally shared here: https://www.djangosnippets.org/snippets/1431/
 """
 
 
-class BaseConverter(object):
+class BaseConverter:
     decimal_digits = "0123456789"
 
     def __init__(self, digits):

datasette/utils/check_callable.py

@@ -1,6 +1,6 @@
 import inspect
 import types
-from typing import NamedTuple, Any
+from typing import Any, NamedTuple
 
 
 class CallableStatus(NamedTuple):
@@ -19,7 +19,7 @@ def check_callable(obj: Any) -> CallableStatus:
     if isinstance(obj, types.FunctionType):
         return CallableStatus(True, inspect.iscoroutinefunction(obj))
 
-    if hasattr(obj, "__call__"):
+    if callable(obj):
         return CallableStatus(True, inspect.iscoroutinefunction(obj.__call__))
 
-    assert False, "obj {} is somehow callable with no __call__ method".format(repr(obj))
+    assert False, f"obj {obj!r} is somehow callable with no __call__ method"

datasette/utils/internal_db.py

@@ -1,9 +1,30 @@
 import textwrap
-from datasette.utils import table_column_details
 
+from sqlite_utils import Database as SQLiteUtilsDatabase
+from sqlite_utils import Migrations
 
-async def init_internal_db(db):
-    create_tables_sql = textwrap.dedent("""
+from datasette.utils import escape_sqlite, table_column_details
+
+INTERNAL_DB_SCHEMA_TABLES = {
+    "catalog_databases",
+    "catalog_tables",
+    "catalog_views",
+    "catalog_columns",
+    "catalog_indexes",
+    "catalog_foreign_keys",
+    "metadata_instance",
+    "metadata_databases",
+    "metadata_resources",
+    "metadata_columns",
+    "column_types",
+    "queries",
+}
+
+INTERNAL_DB_SCHEMA_INDEXES = {
+    "queries_owner_idx",
+}
+
+INTERNAL_DB_SCHEMA_SQL = textwrap.dedent("""
     CREATE TABLE IF NOT EXISTS catalog_databases (
         database_name TEXT PRIMARY KEY,
         path TEXT,
@@ -67,99 +88,101 @@ async def init_internal_db(db):
         FOREIGN KEY (database_name) REFERENCES catalog_databases(database_name),
         FOREIGN KEY (database_name, table_name) REFERENCES catalog_tables(database_name, table_name)
     );
+
+    CREATE TABLE IF NOT EXISTS metadata_instance (
+        key text,
+        value text,
+        unique(key)
+    );
+
+    CREATE TABLE IF NOT EXISTS metadata_databases (
+        database_name text,
+        key text,
+        value text,
+        unique(database_name, key)
+    );
+
+    CREATE TABLE IF NOT EXISTS metadata_resources (
+        database_name text,
+        resource_name text,
+        key text,
+        value text,
+        unique(database_name, resource_name, key)
+    );
+
+    CREATE TABLE IF NOT EXISTS metadata_columns (
+        database_name text,
+        resource_name text,
+        column_name text,
+        key text,
+        value text,
+        unique(database_name, resource_name, column_name, key)
+    );
+
+    CREATE TABLE IF NOT EXISTS column_types (
+        database_name TEXT NOT NULL,
+        resource_name TEXT NOT NULL,
+        column_name TEXT NOT NULL,
+        column_type TEXT NOT NULL,
+        config TEXT,
+        PRIMARY KEY (database_name, resource_name, column_name)
+    );
+
+    CREATE TABLE IF NOT EXISTS queries (
+        database_name TEXT NOT NULL,
+        name TEXT NOT NULL,
+        sql TEXT NOT NULL,
+        title TEXT,
+        description TEXT,
+        description_html TEXT,
+        options TEXT NOT NULL DEFAULT '{}',
+        parameters TEXT NOT NULL DEFAULT '[]',
+        is_write INTEGER NOT NULL DEFAULT 0 CHECK (is_write IN (0, 1)),
+        is_private INTEGER NOT NULL DEFAULT 0 CHECK (is_private IN (0, 1)),
+        is_trusted INTEGER NOT NULL DEFAULT 0 CHECK (is_trusted IN (0, 1)),
+        source TEXT NOT NULL DEFAULT 'user',
+        owner_id TEXT,
+        created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
+        updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
+        PRIMARY KEY (database_name, name)
+    );
+
+    CREATE INDEX IF NOT EXISTS queries_owner_idx
+        ON queries(owner_id);
     """).strip()
-    await db.execute_write_script(create_tables_sql)
-    await initialize_metadata_tables(db)
 
 
-async def initialize_metadata_tables(db):
-    await db.execute_write_script(textwrap.dedent("""
-        CREATE TABLE IF NOT EXISTS metadata_instance (
-            key text,
-            value text,
-            unique(key)
-        );
-
-        CREATE TABLE IF NOT EXISTS metadata_databases (
-            database_name text,
-            key text,
-            value text,
-            unique(database_name, key)
-        );
-
-        CREATE TABLE IF NOT EXISTS metadata_resources (
-            database_name text,
-            resource_name text,
-            key text,
-            value text,
-            unique(database_name, resource_name, key)
-        );
-
-        CREATE TABLE IF NOT EXISTS metadata_columns (
-            database_name text,
-            resource_name text,
-            column_name text,
-            key text,
-            value text,
-            unique(database_name, resource_name, column_name, key)
-        );
-
-        CREATE TABLE IF NOT EXISTS column_types (
-            database_name TEXT NOT NULL,
-            resource_name TEXT NOT NULL,
-            column_name TEXT NOT NULL,
-            column_type TEXT NOT NULL,
-            config TEXT,
-            PRIMARY KEY (database_name, resource_name, column_name)
-        );
-
-        CREATE TABLE IF NOT EXISTS queries (
-            database_name TEXT NOT NULL,
-            name TEXT NOT NULL,
-            sql TEXT NOT NULL,
-            title TEXT,
-            description TEXT,
-            description_html TEXT,
-            options TEXT NOT NULL DEFAULT '{}',
-            parameters TEXT NOT NULL DEFAULT '[]',
-            is_write INTEGER NOT NULL DEFAULT 0 CHECK (is_write IN (0, 1)),
-            is_private INTEGER NOT NULL DEFAULT 0 CHECK (is_private IN (0, 1)),
-            is_trusted INTEGER NOT NULL DEFAULT 0 CHECK (is_trusted IN (0, 1)),
-            source TEXT NOT NULL DEFAULT 'user',
-            owner_id TEXT,
-            created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
-            updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
-            PRIMARY KEY (database_name, name)
-        );
-
-        CREATE INDEX IF NOT EXISTS queries_owner_idx
-            ON queries(owner_id);
-            """))
+internal_migrations = Migrations("datasette_internal")
 
 
-async def populate_schema_tables(internal_db, db):
+def _internal_schema_exists(db):
+    table_names = set(db.table_names())
+    if not INTERNAL_DB_SCHEMA_TABLES.issubset(table_names):
+        return False
+    index_names = {
+        row[0]
+        for row in db.execute("select name from sqlite_master where type = 'index'")
+    }
+    return INTERNAL_DB_SCHEMA_INDEXES.issubset(index_names)
+
+
+@internal_migrations(name="0001_initial")
+def initial_internal_schema(db):
+    if _internal_schema_exists(db):
+        return
+    db.executescript(INTERNAL_DB_SCHEMA_SQL)
+
+
+async def init_internal_db(db):
+    def apply_migrations(conn):
+        internal_migrations.apply(SQLiteUtilsDatabase(conn, execute_plugins=False))
+
+    await db.execute_write_fn(apply_migrations, transaction=False)
+
+
+async def populate_schema_tables(internal_db, db, schema_version):
     database_name = db.name
 
-    def delete_everything(conn):
-        conn.execute(
-            "DELETE FROM catalog_tables WHERE database_name = ?", [database_name]
-        )
-        conn.execute(
-            "DELETE FROM catalog_views WHERE database_name = ?", [database_name]
-        )
-        conn.execute(
-            "DELETE FROM catalog_columns WHERE database_name = ?", [database_name]
-        )
-        conn.execute(
-            "DELETE FROM catalog_foreign_keys WHERE database_name = ?",
-            [database_name],
-        )
-        conn.execute(
-            "DELETE FROM catalog_indexes WHERE database_name = ?", [database_name]
-        )
-
-    await internal_db.execute_write_fn(delete_everything)
-
     tables = (await db.execute("select * from sqlite_master WHERE type = 'table'")).rows
     views = (await db.execute("select * from sqlite_master WHERE type = 'view'")).rows
 
@@ -184,25 +207,30 @@ async def populate_schema_tables(internal_db, db):
             columns = table_column_details(conn, table_name)
             columns_to_insert.extend(
                 {
-                    **{"database_name": database_name, "table_name": table_name},
+                    "database_name": database_name,
+                    "table_name": table_name,
                     **column._asdict(),
                 }
                 for column in columns
             )
             foreign_keys = conn.execute(
-                f"PRAGMA foreign_key_list([{table_name}])"
+                f"PRAGMA foreign_key_list({escape_sqlite(table_name)})"
             ).fetchall()
             foreign_keys_to_insert.extend(
                 {
-                    **{"database_name": database_name, "table_name": table_name},
+                    "database_name": database_name,
+                    "table_name": table_name,
                     **dict(foreign_key),
                 }
                 for foreign_key in foreign_keys
             )
-            indexes = conn.execute(f"PRAGMA index_list([{table_name}])").fetchall()
+            indexes = conn.execute(
+                f"PRAGMA index_list({escape_sqlite(table_name)})"
+            ).fetchall()
             indexes_to_insert.extend(
                 {
-                    **{"database_name": database_name, "table_name": table_name},
+                    "database_name": database_name,
+                    "table_name": table_name,
                     **dict(index),
                 }
                 for index in indexes
@@ -223,47 +251,76 @@ async def populate_schema_tables(internal_db, db):
         indexes_to_insert,
     ) = await db.execute_fn(collect_info)
 
-    await internal_db.execute_write_many(
-        """
-        INSERT INTO catalog_tables (database_name, table_name, rootpage, sql)
-        values (?, ?, ?, ?)
-    """,
-        tables_to_insert,
-    )
-    await internal_db.execute_write_many(
-        """
-        INSERT INTO catalog_views (database_name, view_name, rootpage, sql)
-        values (?, ?, ?, ?)
-    """,
-        views_to_insert,
-    )
-    await internal_db.execute_write_many(
-        """
-        INSERT INTO catalog_columns (
-            database_name, table_name, cid, name, type, "notnull", default_value, is_pk, hidden
-        ) VALUES (
-            :database_name, :table_name, :cid, :name, :type, :notnull, :default_value, :is_pk, :hidden
+    def replace_catalog(conn):
+        # Delete child rows before their catalog_tables parents so this also
+        # works if a prepare_connection plugin enables foreign key enforcement.
+        for table in (
+            "catalog_columns",
+            "catalog_foreign_keys",
+            "catalog_indexes",
+            "catalog_views",
+            "catalog_tables",
+        ):
+            conn.execute(
+                f"DELETE FROM {table} WHERE database_name = ?",
+                [database_name],
+            )
+        conn.execute(
+            """
+            INSERT OR REPLACE INTO catalog_databases (
+                database_name, path, is_memory, schema_version
+            ) VALUES (?, ?, ?, ?)
+            """,
+            [
+                database_name,
+                str(db.path) if db.path is not None else None,
+                db.is_memory,
+                schema_version,
+            ],
         )
-    """,
-        columns_to_insert,
-    )
-    await internal_db.execute_write_many(
-        """
-        INSERT INTO catalog_foreign_keys (
-            database_name, table_name, "id", seq, "table", "from", "to", on_update, on_delete, match
-        ) VALUES (
-            :database_name, :table_name, :id, :seq, :table, :from, :to, :on_update, :on_delete, :match
+        conn.executemany(
+            """
+            INSERT INTO catalog_tables (database_name, table_name, rootpage, sql)
+            values (?, ?, ?, ?)
+            """,
+            tables_to_insert,
         )
-    """,
-        foreign_keys_to_insert,
-    )
-    await internal_db.execute_write_many(
-        """
-        INSERT INTO catalog_indexes (
-            database_name, table_name, seq, name, "unique", origin, partial
-        ) VALUES (
-            :database_name, :table_name, :seq, :name, :unique, :origin, :partial
+        conn.executemany(
+            """
+            INSERT INTO catalog_views (database_name, view_name, rootpage, sql)
+            values (?, ?, ?, ?)
+            """,
+            views_to_insert,
         )
-    """,
-        indexes_to_insert,
-    )
+        conn.executemany(
+            """
+            INSERT INTO catalog_columns (
+                database_name, table_name, cid, name, type, "notnull", default_value, is_pk, hidden
+            ) VALUES (
+                :database_name, :table_name, :cid, :name, :type, :notnull, :default_value, :is_pk, :hidden
+            )
+            """,
+            columns_to_insert,
+        )
+        conn.executemany(
+            """
+            INSERT INTO catalog_foreign_keys (
+                database_name, table_name, "id", seq, "table", "from", "to", on_update, on_delete, match
+            ) VALUES (
+                :database_name, :table_name, :id, :seq, :table, :from, :to, :on_update, :on_delete, :match
+            )
+            """,
+            foreign_keys_to_insert,
+        )
+        conn.executemany(
+            """
+            INSERT INTO catalog_indexes (
+                database_name, table_name, seq, name, "unique", origin, partial
+            ) VALUES (
+                :database_name, :table_name, :seq, :name, :unique, :origin, :partial
+            )
+            """,
+            indexes_to_insert,
+        )
+
+    await internal_db.execute_write_fn(replace_catalog)