query_actions plugin hook

* New query_actions plugin hook, closes #2283

tests/fixtures.py

@@ -46,6 +46,7 @@ EXPECTED_PLUGINS = [
             "permission_allowed",
             "prepare_connection",
             "prepare_jinja2_environment",
+            "query_actions",
             "register_facet_classes",
             "register_magic_parameters",
             "register_permissions",

tests/plugins/my_plugin.py

@@ -7,6 +7,7 @@ from datasette.utils.asgi import asgi_send_json, Response
 import base64
 import pint
 import json
+import urllib
 
 ureg = pint.UnitRegistry()
 
@@ -390,6 +391,23 @@ def table_actions(datasette, database, table, actor):
         ]
 
 
+@hookimpl
+def query_actions(datasette, database, query_name, sql):
+    args = {
+        "sql": sql,
+    }
+    if query_name:
+        args["query_name"] = query_name
+    return [
+        {
+            "href": datasette.urls.database(database)
+            + "/-/explain?"
+            + urllib.parse.urlencode(args),
+            "label": "Explain this query",
+        },
+    ]
+
+
 @hookimpl
 def database_actions(datasette, database, actor, request):
     if actor:

tests/test_plugins.py

@@ -945,6 +945,31 @@ async def test_hook_table_actions(ds_client, table_or_view):
     ]
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "path,expected_url",
+    (
+        ("/fixtures?sql=select+1", "/fixtures/-/explain?sql=select+1"),
+        (
+            "/fixtures/pragma_cache_size",
+            "/fixtures/-/explain?sql=PRAGMA+cache_size%3B&query_name=pragma_cache_size",
+        ),
+    ),
+)
+async def test_hook_query_actions(ds_client, path, expected_url):
+    def get_table_actions_links(html):
+        soup = Soup(html, "html.parser")
+        details = soup.find("details", {"class": "actions-menu-links"})
+        if details is None:
+            return []
+        return [{"label": a.text, "href": a["href"]} for a in details.select("a")]
+
+    response = await ds_client.get(path)
+    assert response.status_code == 200
+    links = get_table_actions_links(response.text)
+    assert links == [{"label": "Explain this query", "href": expected_url}]
+
+
 @pytest.mark.asyncio
 async def test_hook_database_actions(ds_client):
     def get_table_actions_links(html):