Precompute action permissions for table pages

- Extract reusable helpers for database and table action permission preloading.
- Precompute those permissions before building table-page HTML data.
- Document the default table actions plugin.

datasette/views/table.py

@@ -54,6 +54,8 @@ from .database import QueryView, _custom_column_type_options_for_create_table
 from .table_extras import (
     TABLE_EXTRA_BUNDLES,
     TableExtraContext,
+    precompute_database_action_permissions,
+    precompute_table_action_permissions,
     resolve_table_extras,
     table_extra_registry,
 )
@@ -1247,7 +1249,10 @@ class TableAlterView(BaseView):
                             defaults[args.name] = _literal_default(
                                 db_for_write, args.default
                             )
-                        if "default_expr" in args.model_fields_set and not args.not_null:
+                        if (
+                            "default_expr" in args.model_fields_set
+                            and not args.not_null
+                        ):
                             defaults[args.name] = _default_expression_sql(
                                 args.default_expr
                             )
@@ -1363,9 +1368,9 @@ class TableAlterView(BaseView):
                 "altered": altered,
                 "schema": after_schema,
                 "before_schema": before_schema,
-                "operations_applied": 0
-                if alter_request.dry_run
-                else len(alter_request.operations),
+                "operations_applied": (
+                    0 if alter_request.dry_run else len(alter_request.operations)
+                ),
                 "dry_run": alter_request.dry_run,
             },
             status=200,
@@ -2068,6 +2073,15 @@ async def table_view_data(
     if redirect_response:
         return redirect_response
 
+    if context_for_html_hack:
+        await precompute_database_action_permissions(
+            datasette, request.actor, database_name
+        )
+        if not is_view:
+            await precompute_table_action_permissions(
+                datasette, request.actor, database_name, table_name
+            )
+
     # Introspect columns and primary keys for table
     pks = await db.primary_keys(table_name)
     table_columns = await db.table_columns(table_name)

datasette/views/table_extras.py

@@ -367,23 +367,14 @@ class ActionsExtra(Extra):
                 # that allowed() calls made inside the plugin hooks below
                 # are served from the cache
                 datasette = context.datasette
-                await datasette.allowed_many(
-                    actions=[
-                        name
-                        for name, action in datasette.actions.items()
-                        if action.resource_class is TableResource
-                    ],
-                    resource=TableResource(context.database_name, context.table_name),
-                    actor=context.request.actor,
+                await precompute_table_action_permissions(
+                    datasette,
+                    context.request.actor,
+                    context.database_name,
+                    context.table_name,
                 )
-                await datasette.allowed_many(
-                    actions=[
-                        name
-                        for name, action in datasette.actions.items()
-                        if action.resource_class is DatabaseResource
-                    ],
-                    resource=DatabaseResource(context.database_name),
-                    actor=context.request.actor,
+                await precompute_database_action_permissions(
+                    datasette, context.request.actor, context.database_name
                 )
             for hook in method(**kwargs):
                 extra_links = await await_me_maybe(hook)
@@ -394,6 +385,32 @@ class ActionsExtra(Extra):
         return actions
 
 
+async def precompute_table_action_permissions(
+    datasette, actor, database_name, table_name
+):
+    await datasette.allowed_many(
+        actions=[
+            name
+            for name, action in datasette.actions.items()
+            if action.resource_class is TableResource
+        ],
+        resource=TableResource(database_name, table_name),
+        actor=actor,
+    )
+
+
+async def precompute_database_action_permissions(datasette, actor, database_name):
+    await datasette.allowed_many(
+        actions=[
+            name
+            for name, action in datasette.actions.items()
+            if action.resource_class is DatabaseResource
+        ],
+        resource=DatabaseResource(database_name),
+        actor=actor,
+    )
+
+
 class IsViewExtra(Extra):
     description = "Whether this resource is a view instead of a table"
     example = ExtraExample("/fixtures/simple_view.json?_extra=is_view")

docs/plugins.rst

@@ -280,6 +280,15 @@ If you run ``datasette plugins --all`` it will include default plugins that ship
                 "query_actions"
             ]
         },
+        {
+            "name": "datasette.default_table_actions",
+            "static": false,
+            "templates": false,
+            "version": null,
+            "hooks": [
+                "table_actions"
+            ]
+        },
         {
             "name": "datasette.events",
             "static": false,

tests/test_playwright.py

@@ -350,7 +350,9 @@ def test_alter_table_flow(page, datasette_server):
     assert first_more_options.inner_text() == "> Advanced options"
     first_more_options.click()
     assert first_more_options.inner_text() == "v Hide options"
-    expanded_options_text = dialog.locator(".table-alter-column-details").first.inner_text()
+    expanded_options_text = dialog.locator(
+        ".table-alter-column-details"
+    ).first.inner_text()
     assert dialog.locator(".table-alter-fields").evaluate(
         "node => node.scrollWidth <= node.clientWidth + 1"
     )
@@ -500,8 +502,7 @@ def test_alter_table_cancel_skips_discard_prompt(page, datasette_server):
         return dialog
 
     page.goto(f"{datasette_server}data/projects")
-    page.evaluate(
-        """
+    page.evaluate("""
         () => {
             window.__discardConfirmMessages = [];
             window.confirm = (message) => {
@@ -509,8 +510,7 @@ def test_alter_table_cancel_skips_discard_prompt(page, datasette_server):
                 return false;
             };
         }
-        """
-    )
+        """)
 
     dialog = open_alter_dialog()
     dialog.locator(".table-alter-add-column").click()