Ability to set custom table/view page size in metadata, closes #751

datasette/views/table.py

@@ -527,7 +527,7 @@ class TableView(RowTableShared):
 
         extra_args = {}
         # Handle ?_size=500
-        page_size = _size or request.args.get("_size")
+        page_size = _size or request.args.get("_size") or table_metadata.get("size")
         if page_size:
             if page_size == "max":
                 page_size = self.ds.max_returned_rows

docs/metadata.rst

@@ -156,6 +156,29 @@ Or use ``"sort_desc"`` to sort in descending order:
         }
     }
 
+.. _metadata_page_size:
+
+Setting a custom page size
+--------------------------
+
+Datasette defaults to displaing 100 rows per page, for both tables and views. You can change this default page size on a per-table or per-view basis using the ``"size"`` key in ``metadata.json``:
+
+.. code-block:: json
+
+    {
+        "databases": {
+            "mydatabase": {
+                "tables": {
+                    "example_table": {
+                        "size": 10
+                    }
+                }
+            }
+        }
+    }
+
+This size can still be over-ridden by passing e.g. ``?_size=50`` in the querystring.
+
 .. _metadata_sortable_columns:
 
 Setting which columns can be used for sorting

tests/fixtures.py

@@ -305,6 +305,7 @@ METADATA = {
                 },
                 "attraction_characteristic": {"sort_desc": "pk"},
                 "facet_cities": {"sort": "name"},
+                "paginated_view": {"size": 25},
             },
             "queries": {
                 "𝐜𝐢𝐭𝐢𝐞𝐬": "select id, name from facet_cities order by id limit 1;",

tests/test_api.py

@@ -754,9 +754,9 @@ def test_table_with_reserved_word_name(app_client):
     "path,expected_rows,expected_pages",
     [
         ("/fixtures/no_primary_key.json", 201, 5),
-        ("/fixtures/paginated_view.json", 201, 5),
+        ("/fixtures/paginated_view.json", 201, 9),
         ("/fixtures/no_primary_key.json?_size=25", 201, 9),
-        ("/fixtures/paginated_view.json?_size=25", 201, 9),
+        ("/fixtures/paginated_view.json?_size=50", 201, 5),
         ("/fixtures/paginated_view.json?_size=max", 201, 3),
         ("/fixtures/123_starts_with_digits.json", 0, 1),
         # Ensure faceting doesn't break pagination: