extra_css_urls(template, database, table, datasette)

The extra_css_urls and extra_js_urls hooks now take additional optional
parameters.

Also refactored them out of the Datasette class and into RenderMixin.

Plus improved plugin documentation to explicitly list parameters.

datasette/app.py

@@ -2,7 +2,6 @@ import asyncio
 import click
 import collections
 import hashlib
-import itertools
 import os
 import sys
 import threading
@@ -258,33 +257,6 @@ class Datasette:
     def get_view_definition(self, database_name, view):
         return self.get_table_definition(database_name, view, 'view')
 
-    def asset_urls(self, key):
-        # Flatten list-of-lists from plugins:
-        seen_urls = set()
-        for url_or_dict in itertools.chain(
-            itertools.chain.from_iterable(getattr(pm.hook, key)()),
-            (self.metadata(key) or [])
-        ):
-            if isinstance(url_or_dict, dict):
-                url = url_or_dict["url"]
-                sri = url_or_dict.get("sri")
-            else:
-                url = url_or_dict
-                sri = None
-            if url in seen_urls:
-                continue
-            seen_urls.add(url)
-            if sri:
-                yield {"url": url, "sri": sri}
-            else:
-                yield {"url": url}
-
-    def extra_css_urls(self):
-        return self.asset_urls("extra_css_urls")
-
-    def extra_js_urls(self):
-        return self.asset_urls("extra_js_urls")
-
     def update_with_inherited_metadata(self, metadata):
         # Fills in source/license with defaults, if available
         metadata.update(

datasette/hookspecs.py

@@ -16,12 +16,12 @@ def prepare_jinja2_environment(env):
 
 
 @hookspec
-def extra_css_urls():
+def extra_css_urls(template, database, table, datasette):
     "Extra CSS URLs added by this plugin"
 
 
 @hookspec
-def extra_js_urls():
+def extra_js_urls(template, database, table, datasette):
     "Extra JavaScript URLs added by this plugin"
 
 

datasette/views/base.py

@@ -1,5 +1,6 @@
 import asyncio
 import csv
+import itertools
 import json
 import re
 import time
@@ -46,6 +47,32 @@ class DatasetteError(Exception):
 
 class RenderMixin(HTTPMethodView):
 
+    def _asset_urls(self, key, template, context):
+        # Flatten list-of-lists from plugins:
+        seen_urls = set()
+        for url_or_dict in itertools.chain(
+            itertools.chain.from_iterable(getattr(pm.hook, key)(
+                template=template.name,
+                database=context.get("database"),
+                table=context.get("table"),
+                datasette=self.ds
+            )),
+            (self.ds.metadata(key) or [])
+        ):
+            if isinstance(url_or_dict, dict):
+                url = url_or_dict["url"]
+                sri = url_or_dict.get("sri")
+            else:
+                url = url_or_dict
+                sri = None
+            if url in seen_urls:
+                continue
+            seen_urls.add(url)
+            if sri:
+                yield {"url": url, "sri": sri}
+            else:
+                yield {"url": url}
+
     def render(self, templates, **context):
         template = self.ds.jinja_env.select_template(templates)
         select_templates = [
@@ -69,6 +96,12 @@ class RenderMixin(HTTPMethodView):
                         "select_templates": select_templates,
                         "zip": zip,
                         "body_scripts": body_scripts,
+                        "extra_css_urls": self._asset_urls(
+                            "extra_css_urls", template, context
+                        ),
+                        "extra_js_urls": self._asset_urls(
+                            "extra_js_urls", template, context
+                        ),
                     }
                 }
             )
@@ -432,8 +465,6 @@ class BaseView(RenderMixin):
                     "url_csv": url_csv,
                     "url_csv_path": url_csv_path,
                     "url_csv_args": url_csv_args,
-                    "extra_css_urls": self.ds.extra_css_urls(),
-                    "extra_js_urls": self.ds.extra_js_urls(),
                     "datasette_version": __version__,
                     "config": self.ds.config_dict(),
                 }

datasette/views/index.py

@@ -51,6 +51,4 @@ class IndexView(RenderMixin):
                 databases=databases,
                 metadata=self.ds.metadata(),
                 datasette_version=__version__,
-                extra_css_urls=self.ds.extra_css_urls(),
-                extra_js_urls=self.ds.extra_js_urls(),
             )

docs/plugins.rst

@@ -231,6 +231,9 @@ The full list of available plugin hooks is as follows.
 prepare_connection(conn)
 ~~~~~~~~~~~~~~~~~~~~~~~~
 
+``conn`` - sqlite3 connection object
+    The connection that is being opened
+
 This hook is called when a new SQLite database connection is created. You can
 use it to `register custom SQL functions <https://docs.python.org/2/library/sqlite3.html#sqlite3.Connection.create_function>`_,
 aggregates and collations. For example:
@@ -252,6 +255,9 @@ arguments and can be called like this::
 prepare_jinja2_environment(env)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+``env`` - jinja2 Environment
+    The template environment that is being prepared
+
 This hook is called with the Jinja2 environment that is used to evaluate
 Datasette HTML templates. You can use it to do things like `register custom
 template filters <http://jinja.pocoo.org/docs/2.10/api/#custom-filters>`_, for
@@ -269,10 +275,22 @@ You can now use this filter in your custom templates like so::
 
     Table name: {{ table|uppercase }}
 
-extra_css_urls()
-~~~~~~~~~~~~~~~~
+extra_css_urls(template, database, table, datasette)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Return a list of extra CSS URLs that should be included on every page. These can
+``template`` - string
+    The template that is being rendered, e.g. ``database.html``
+
+``database`` - string or None
+    The name of the database
+
+``table`` - string or None
+    The name of the table
+
+``datasette`` - Datasette instance
+    You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``
+
+Return a list of extra CSS URLs that should be included on the page. These can
 take advantage of the CSS class hooks described in :ref:`customization`.
 
 This can be a list of URLs:
@@ -301,8 +319,10 @@ Or a list of dictionaries defining both a URL and an
             'sri': 'sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4',
         }]
 
-extra_js_urls()
-~~~~~~~~~~~~~~~
+extra_js_urls(template, database, table, datasette)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Same arguments as ``extra_css_urls``.
 
 This works in the same way as ``extra_css_urls()`` but for JavaScript. You can
 return either a list of URLs or a list of dictionaries:
@@ -334,6 +354,9 @@ you have one:
 publish_subcommand(publish)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+``publish`` - Click publish command group
+    The Click command group for the ``datasette publish`` subcommand
+
 This hook allows you to create new providers for the ``datasette publish``
 command. Datasette uses this hook internally to implement the default ``now``
 and ``heroku`` subcommands, so you can read
@@ -351,8 +374,8 @@ Lets you customize the display of values within table cells in the HTML table vi
 ``column`` - string
     The name of the column being rendered
 
-``table`` - string
-    The name of the table
+``table`` - string or None
+    The name of the table - or ``None`` if this is a custom SQL query
 
 ``database`` - string
     The name of the database
@@ -411,6 +434,18 @@ If the value matches that pattern, the plugin returns an HTML link element:
 extra_body_script(template, database, table, datasette)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+``template`` - string
+    The template that is being rendered, e.g. ``database.html``
+
+``database`` - string or None
+    The name of the database, or ``None`` if the page does not correspond to a database (e.g. the root page)
+
+``table`` - string or None
+    The name of the table, or ``None`` if the page does not correct to a table
+
+``datasette`` - Datasette instance
+    You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``
+
 Extra JavaScript to be added to a ``<script>`` block at the end of the ``<body>`` element on the page.
 
 The ``template``, ``database`` and ``table`` options can be used to return different code depending on which template is being rendered and which database or table are being processed.

tests/fixtures.py

@@ -204,6 +204,7 @@ METADATA = {
 
 PLUGIN1 = '''
 from datasette import hookimpl
+import base64
 import pint
 import json
 
@@ -219,8 +220,14 @@ def prepare_connection(conn):
 
 
 @hookimpl
-def extra_css_urls():
-    return ['https://example.com/app.css']
+def extra_css_urls(template, database, table, datasette):
+    return ['https://example.com/{}/extra-css-urls-demo.css'.format(
+        base64.b64encode(json.dumps({
+            "template": template,
+            "database": database,
+            "table": table,
+        }).encode("utf8")).decode("utf8")
+    )]
 
 
 @hookimpl

tests/test_plugins.py

@@ -2,6 +2,7 @@ from bs4 import BeautifulSoup as Soup
 from .fixtures import ( # noqa
     app_client,
 )
+import base64
 import json
 import re
 import pytest
@@ -15,16 +16,44 @@ def test_plugins_dir_plugin(app_client):
     assert pytest.approx(328.0839) == response.json['rows'][0][0]
 
 
-def test_plugin_extra_css_urls(app_client):
-    response = app_client.get('/')
+@pytest.mark.parametrize(
+    "path,expected_decoded_object",
+    [
+        (
+            "/",
+            {
+                "template": "index.html",
+                "database": None,
+                "table": None,
+            },
+        ),
+        (
+            "/fixtures/",
+            {
+                "template": "database.html",
+                "database": "fixtures",
+                "table": None,
+            },
+        ),
+        (
+            "/fixtures/sortable",
+            {
+                "template": "table.html",
+                "database": "fixtures",
+                "table": "sortable",
+            },
+        ),
+    ],
+)
+def test_plugin_extra_css_urls(app_client, path, expected_decoded_object):
+    response = app_client.get(path)
     links = Soup(response.body, 'html.parser').findAll('link')
-    assert [
-        l for l in links
-        if l.attrs == {
-            'rel': ['stylesheet'],
-            'href': 'https://example.com/app.css'
-        }
-    ]
+    special_href = [
+        l for l in links if l.attrs["href"].endswith("/extra-css-urls-demo.css")
+    ][0]["href"]
+    # This link has a base64-encoded JSON blob in it
+    encoded = special_href.split("/")[3]
+    assert expected_decoded_object == json.loads(base64.b64decode(encoded))
 
 
 def test_plugin_extra_js_urls(app_client):