Fixed bug with download of BLOB null, refs #1050

datasette/views/table.py

@@ -1083,7 +1083,7 @@ class BlobView(BaseView):
             "Content-Disposition": 'attachment; filename="{}"'.format(filename),
         }
         return Response(
-            body=rows[0][column],
+            body=rows[0][column] or b"",
             status=200,
             headers=headers,
             content_type="application/binary",

tests/fixtures.py

@@ -667,6 +667,7 @@ CREATE VIEW searchable_view_configured_by_metadata AS
 TABLE_PARAMETERIZED_SQL = [
     ("insert into binary_data (data) values (?);", [b"\x15\x1c\x02\xc7\xad\x05\xfe"]),
     ("insert into binary_data (data) values (?);", [b"\x15\x1c\x03\xc7\xad\x05\xfe"]),
+    ("insert into binary_data (data) values (null);", []),
 ]
 
 EXTRA_DATABASE_SQL = """

tests/test_api.py

@@ -106,7 +106,7 @@ def test_database_page(app_client):
             "name": "binary_data",
             "columns": ["data"],
             "primary_keys": [],
-            "count": 2,
+            "count": 3,
             "hidden": False,
             "fts_table": None,
             "foreign_keys": {"incoming": [], "outgoing": []},
@@ -1812,6 +1812,7 @@ def test_inspect_file_used_for_count(app_client_immutable_and_inspect_file):
             [
                 {"rowid": 1, "data": {"$base64": True, "encoded": "FRwCx60F/g=="}},
                 {"rowid": 2, "data": {"$base64": True, "encoded": "FRwDx60F/g=="}},
+                {"rowid": 3, "data": None},
             ],
             None,
         ),
@@ -1820,7 +1821,8 @@ def test_inspect_file_used_for_count(app_client_immutable_and_inspect_file):
             None,
             (
                 '{"rowid": 1, "data": {"$base64": true, "encoded": "FRwCx60F/g=="}}\n'
-                '{"rowid": 2, "data": {"$base64": true, "encoded": "FRwDx60F/g=="}}'
+                '{"rowid": 2, "data": {"$base64": true, "encoded": "FRwDx60F/g=="}}\n'
+                '{"rowid": 3, "data": null}'
             ),
         ),
     ],

tests/test_html.py

@@ -1238,21 +1238,36 @@ def test_binary_data_display(app_client):
             '<td class="col-rowid type-int">2</td>',
             '<td class="col-data type-bytes"><a class="blob-download" href="/fixtures/binary_data/-/blob/2/data.blob">&lt;Binary:\xa07\xa0bytes&gt;</a></td>',
         ],
+        [
+            '<td class="col-Link type-pk"><a href="/fixtures/binary_data/3">3</a></td>',
+            '<td class="col-rowid type-int">3</td>',
+            '<td class="col-data type-none">\xa0</td>',
+        ],
     ]
     assert expected_tds == [
         [str(td) for td in tr.select("td")] for tr in table.select("tbody tr")
     ]
 
 
-def test_blob_download(app_client):
-    response = app_client.get("/fixtures/binary_data/-/blob/1/data.blob")
+@pytest.mark.parametrize(
+    "path,expected_body,expected_filename",
+    [
+        (
+            "/fixtures/binary_data/-/blob/1/data.blob",
+            b"\x15\x1c\x02\xc7\xad\x05\xfe",
+            "binary_data-1-data.blob",
+        ),
+        ("/fixtures/binary_data/-/blob/3/data.blob", b"", "binary_data-3-data.blob"),
+    ],
+)
+def test_blob_download(app_client, path, expected_body, expected_filename):
+    response = app_client.get(path)
     assert response.status == 200
-    assert response.body == b"\x15\x1c\x02\xc7\xad\x05\xfe"
+    assert response.body == expected_body
     assert response.headers["x-content-type-options"] == "nosniff"
-    assert (
-        response.headers["content-disposition"]
-        == 'attachment; filename="binary_data-1-data.blob"'
-    )
+    assert response.headers[
+        "content-disposition"
+    ] == 'attachment; filename="{}"'.format(expected_filename)
     assert response.headers["content-type"] == "application/binary"