render_cell() can now return an awaitable, refs

datasette/views/database.py

@@ -361,6 +361,7 @@ class QueryView(DataView):
                         database=database,
                         datasette=self.ds,
                     )
+                    plugin_value = await await_me_maybe(plugin_value)
                     if plugin_value is not None:
                         display_value = plugin_value
                     else:

datasette/views/table.py

@@ -198,6 +198,7 @@ class RowTableShared(DataView):
                     database=database,
                     datasette=self.ds,
                 )
+                plugin_display_value = await await_me_maybe(plugin_display_value)
                 if plugin_display_value is not None:
                     display_value = plugin_display_value
                 elif isinstance(value, bytes):

docs/plugin_hooks.rst

@@ -370,7 +370,7 @@ Lets you customize the display of values within table cells in the HTML table vi
     The name of the database
 
 ``datasette`` - :ref:`internals_datasette`
-    You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``
+    You can use this to access plugin configuration options via ``datasette.plugin_config(your_plugin_name)``, or to execute SQL queries.
 
 If your hook returns ``None``, it will be ignored. Use this to indicate that your hook is not able to custom render this particular value.
 
@@ -378,6 +378,8 @@ If the hook returns a string, that string will be rendered in the table cell.
 
 If you want to return HTML markup you can do so by returning a ``jinja2.Markup`` object.
 
+You can also return an awaitable function which returns a value.
+
 Datasette will loop through all available ``render_cell`` hooks and display the value returned by the first one that does not return ``None``.
 
 Here is an example of a custom ``render_cell()`` plugin which looks for values that are a JSON string matching the following format::

tests/fixtures.py

@@ -644,6 +644,7 @@ INSERT INTO simple_primary_key VALUES (1, 'hello');
 INSERT INTO simple_primary_key VALUES (2, 'world');
 INSERT INTO simple_primary_key VALUES (3, '');
 INSERT INTO simple_primary_key VALUES (4, 'RENDER_CELL_DEMO');
+INSERT INTO simple_primary_key VALUES (5, 'RENDER_CELL_ASYNC');
 
 INSERT INTO primary_key_multiple_columns VALUES (1, 'hey', 'world');
 INSERT INTO primary_key_multiple_columns_explicit_label VALUES (1, 'hey', 'world2');

tests/plugins/my_plugin.py

@@ -97,21 +97,29 @@ def extra_body_script(
 
 @hookimpl
 def render_cell(value, column, table, database, datasette):
-    # Render some debug output in cell with value RENDER_CELL_DEMO
+    async def inner():
-    if value != "RENDER_CELL_DEMO":
+        # Render some debug output in cell with value RENDER_CELL_DEMO
-        return None
+        if value == "RENDER_CELL_DEMO":
-    return json.dumps(
+            return json.dumps(
-        {
+                {
-            "column": column,
+                    "column": column,
-            "table": table,
+                    "table": table,
-            "database": database,
+                    "database": database,
-            "config": datasette.plugin_config(
+                    "config": datasette.plugin_config(
-                "name-of-plugin",
+                        "name-of-plugin",
-                database=database,
+                        database=database,
-                table=table,
+                        table=table,
-            ),
+                    ),
-        }
+                }
-    )
+            )
+        elif value == "RENDER_CELL_ASYNC":
+            return (
+                await datasette.get_database(database).execute(
+                    "select 'RENDER_CELL_ASYNC_RESULT'"
+                )
+            ).single_value()
+
+    return inner
 
 
 @hookimpl

tests/test_api.py

@@ -415,7 +415,7 @@ def test_database_page(app_client):
             "name": "simple_primary_key",
             "columns": ["id", "content"],
             "primary_keys": ["id"],
-            "count": 4,
+            "count": 5,
             "hidden": False,
             "fts_table": None,
             "foreign_keys": {
@@ -652,6 +652,7 @@ def test_custom_sql(app_client):
         {"content": "world"},
         {"content": ""},
         {"content": "RENDER_CELL_DEMO"},
+        {"content": "RENDER_CELL_ASYNC"},
     ] == data["rows"]
     assert ["content"] == data["columns"]
     assert "fixtures" == data["database"]
@@ -693,6 +694,7 @@ def test_table_json(app_client):
         {"id": "2", "content": "world"},
         {"id": "3", "content": ""},
         {"id": "4", "content": "RENDER_CELL_DEMO"},
+        {"id": "5", "content": "RENDER_CELL_ASYNC"},
     ]
 
 
@@ -723,6 +725,7 @@ def test_table_shape_arrays(app_client):
         ["2", "world"],
         ["3", ""],
         ["4", "RENDER_CELL_DEMO"],
+        ["5", "RENDER_CELL_ASYNC"],
     ] == response.json["rows"]
 
 
@@ -736,7 +739,13 @@ def test_table_shape_arrayfirst(app_client):
             }
         )
     )
-    assert ["hello", "world", "", "RENDER_CELL_DEMO"] == response.json
+    assert [
+        "hello",
+        "world",
+        "",
+        "RENDER_CELL_DEMO",
+        "RENDER_CELL_ASYNC",
+    ] == response.json
 
 
 def test_table_shape_objects(app_client):
@@ -746,6 +755,7 @@ def test_table_shape_objects(app_client):
         {"id": "2", "content": "world"},
         {"id": "3", "content": ""},
         {"id": "4", "content": "RENDER_CELL_DEMO"},
+        {"id": "5", "content": "RENDER_CELL_ASYNC"},
     ] == response.json["rows"]
 
 
@@ -756,6 +766,7 @@ def test_table_shape_array(app_client):
         {"id": "2", "content": "world"},
         {"id": "3", "content": ""},
         {"id": "4", "content": "RENDER_CELL_DEMO"},
+        {"id": "5", "content": "RENDER_CELL_ASYNC"},
     ] == response.json
 
 
@@ -768,6 +779,7 @@ def test_table_shape_array_nl(app_client):
         {"id": "2", "content": "world"},
         {"id": "3", "content": ""},
         {"id": "4", "content": "RENDER_CELL_DEMO"},
+        {"id": "5", "content": "RENDER_CELL_ASYNC"},
     ] == results
 
 
@@ -788,6 +800,7 @@ def test_table_shape_object(app_client):
         "2": {"id": "2", "content": "world"},
         "3": {"id": "3", "content": ""},
         "4": {"id": "4", "content": "RENDER_CELL_DEMO"},
+        "5": {"id": "5", "content": "RENDER_CELL_ASYNC"},
     } == response.json
 
 
@@ -1145,12 +1158,21 @@ def test_searchable_invalid_column(app_client):
         ("/fixtures/simple_primary_key.json?content=hello", [["1", "hello"]]),
         (
             "/fixtures/simple_primary_key.json?content__contains=o",
-            [["1", "hello"], ["2", "world"], ["4", "RENDER_CELL_DEMO"]],
+            [
+                ["1", "hello"],
+                ["2", "world"],
+                ["4", "RENDER_CELL_DEMO"],
+            ],
         ),
         ("/fixtures/simple_primary_key.json?content__exact=", [["3", ""]]),
         (
             "/fixtures/simple_primary_key.json?content__not=world",
-            [["1", "hello"], ["3", ""], ["4", "RENDER_CELL_DEMO"]],
+            [
+                ["1", "hello"],
+                ["3", ""],
+                ["4", "RENDER_CELL_DEMO"],
+                ["5", "RENDER_CELL_ASYNC"],
+            ],
         ),
     ],
 )
@@ -1163,7 +1185,11 @@ def test_table_filter_queries_multiple_of_same_type(app_client):
     response = app_client.get(
         "/fixtures/simple_primary_key.json?content__not=world&content__not=hello"
     )
-    assert [["3", ""], ["4", "RENDER_CELL_DEMO"]] == response.json["rows"]
+    assert [
+        ["3", ""],
+        ["4", "RENDER_CELL_DEMO"],
+        ["5", "RENDER_CELL_ASYNC"],
+    ] == response.json["rows"]
 
 
 @pytest.mark.skipif(not detect_json1(), reason="Requires the SQLite json1 module")
@@ -1293,6 +1319,7 @@ def test_view(app_client):
         {"upper_content": "WORLD", "content": "world"},
         {"upper_content": "", "content": ""},
         {"upper_content": "RENDER_CELL_DEMO", "content": "RENDER_CELL_DEMO"},
+        {"upper_content": "RENDER_CELL_ASYNC", "content": "RENDER_CELL_ASYNC"},
     ]
 
 

tests/test_plugins.py

@@ -185,6 +185,11 @@ def test_hook_render_cell_demo(app_client):
     } == json.loads(td.string)
 
 
+def test_hook_render_cell_async(app_client):
+    response = app_client.get("/fixtures?sql=select+'RENDER_CELL_ASYNC'")
+    assert b"RENDER_CELL_ASYNC_RESULT" in response.body
+
+
 def test_plugin_config(app_client):
     assert {"depth": "table"} == app_client.ds.plugin_config(
         "name-of-plugin", database="fixtures", table="sortable"