Fix table CSV exports to ignore max_csv_mb

datasette/views/base.py

@@ -472,7 +472,11 @@ async def stream_csv(datasette, fetch_data, request, database):
 
     async def stream_fn(r):
         nonlocal data, trace
-        limited_writer = LimitedWriter(r, datasette.setting("max_csv_mb"))
+        # Table exports should not be constrained by max_csv_mb - that limit
+        # is intended for arbitrary query exports.
+        is_table_export = request.url_vars.get("table") is not None
+        max_csv_mb = 0 if is_table_export else datasette.setting("max_csv_mb")
+        limited_writer = LimitedWriter(r, max_csv_mb)
         if trace:
             await limited_writer.write(preamble)
             writer = csv.writer(EscapeHtmlWriter(limited_writer))

docs/plugin_hooks.rst

@@ -957,6 +957,25 @@ The fields of the ``Action`` dataclass are as follows:
     - Implement a ``resources_sql()`` classmethod that returns SQL returning all resources as ``(parent, child)`` columns
     - Have an ``__init__`` method that accepts appropriate parameters and calls ``super().__init__(parent=..., child=...)``
 
+Checking a registered action
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To check one of these actions in your plugin code, call
+``datasette.allowed()`` with both the action name and a resource instance.
+For example, this checks if the current actor can view a specific
+``DocumentResource``:
+
+.. code-block:: python
+
+    async def can_view_document(
+        datasette, actor, collection, document_id
+    ):
+        return await datasette.allowed(
+            actor,
+            "view-document",
+            resource=DocumentResource(collection, document_id),
+        )
+
 The ``resources_sql()`` method
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

tests/test_csv.py

@@ -185,6 +185,23 @@ async def test_csv_with_non_ascii_characters(ds_client):
     assert response.text == "text,number\r\n𝐜𝐢𝐭𝐢𝐞𝐬,1\r\nbob,2\r\n"
 
 
+@pytest.mark.asyncio
+async def test_table_csv_ignores_max_csv_mb():
+    ds = Datasette(settings={"max_csv_mb": 1})
+    await ds.invoke_startup()
+    db = ds.add_memory_database("max_csv")
+    await db.execute_write("create table t (id integer primary key, content text)")
+    await db.execute_write(
+        "insert into t (content) values (?)",
+        ["a" * (2 * 1024 * 1024)],
+    )
+
+    response = await ds.client.get("/max_csv/t.csv")
+    assert response.status_code == 200
+    assert "CSV contains more than" not in response.text
+    assert len([line for line in response.text.split("\r\n") if line]) == 2
+
+
 @pytest.mark.xfail(reason="Flaky, see https://github.com/simonw/datasette/issues/2355")
 def test_max_csv_mb(app_client_csv_max_mb_one):
     # This query deliberately generates a really long string