Truncate displayed link text for the url column type

datasette/default_column_types.py

@@ -5,6 +5,7 @@
 
 from datasette import hookimpl
 from datasette.column_types import ColumnType, SQLiteType
+from datasette.utils import truncate_url
 
 
 class UrlColumnType(ColumnType):
@@ -15,8 +16,12 @@ class UrlColumnType(ColumnType):
     async def render_cell(self, value, column, table, database, datasette, request):
         if not value or not isinstance(value, str):
             return None
-        escaped = markupsafe.escape(value.strip())
-        return markupsafe.Markup(f'<a href="{escaped}">{escaped}</a>')
+        url = value.strip()
+        escaped = markupsafe.escape(url)
+        truncated = markupsafe.escape(
+            truncate_url(url, datasette.setting("truncate_cells_html"))
+        )
+        return markupsafe.Markup(f'<a href="{escaped}">{truncated}</a>')
 
     async def validate(self, value, datasette):
         if value is None or value == "":

docs/changelog.rst

@@ -93,6 +93,7 @@ The edit interface takes :ref:`custom column types <table_configuration_column_t
 - Permission checks are now cached on a per-request basis, speeding up table pages with multiple plugins that check permissions in order to populate the :ref:`table actions menu <plugin_hook_table_actions>`.
 - Fixed a warning about ``gen.throw(*sys.exc_info())``. (:issue:`2776`)
 - New default custom column type ``textarea`` for multi-line text content. This is rendered as a ``<textarea>`` input in the edit UI.
+- Links rendered by the ``url`` :ref:`custom column type <table_configuration_column_types>` now have their displayed text truncated according to the :ref:`setting_truncate_cells_html` setting, while still linking to the full URL. (:issue:`1805`)
 - The ``json`` column type now implements client-side validation in the edit UI.
 - The :ref:`makeColumnField() <javascript_plugins_makeColumnField>` JavaScript plugin hook allows plugins to define custom fields in the edit interface for their custom column types.
 - New UI for inserting, editing, and deleting rows within Datasette. (:issue:`2780`)

tests/test_column_types.py

@@ -568,6 +568,44 @@ async def test_url_render_cell(ds_ct):
     assert "https://example.com" in rendered["website"]
 
 
+@pytest.mark.asyncio
+async def test_url_render_cell_truncates(tmp_path_factory):
+    # truncate_cells_html should also truncate the displayed text of url
+    # column type links, while keeping the full URL in the href - refs #1805
+    db_directory = tmp_path_factory.mktemp("dbs")
+    db_path = str(db_directory / "data.db")
+    db = sqlite3.connect(db_path)
+    db.execute("create table posts (id integer primary key, website text)")
+    long_url = (
+        "https://images.openfoodfacts.org/images/products/000/000/000/088/"
+        "nutrition_fr.5.200.jpg"
+    )
+    db.execute("insert into posts values (1, ?)", [long_url])
+    db.commit()
+    db.close()
+    ds = Datasette(
+        [db_path],
+        settings={"truncate_cells_html": 30},
+        config={
+            "databases": {
+                "data": {"tables": {"posts": {"column_types": {"website": "url"}}}}
+            }
+        },
+    )
+    await ds.invoke_startup()
+    response = await ds.client.get("/data/posts.json?_extra=render_cell")
+    assert response.status_code == 200
+    rendered = response.json()["render_cell"][0]["website"]
+    # The full URL is preserved in the href
+    assert f'href="{long_url}"' in rendered
+    # ...but the visible link text is truncated
+    soup = Soup(rendered, "html.parser")
+    link_text = soup.find("a").text
+    assert link_text != long_url
+    assert "…" in link_text
+    ds.close()
+
+
 @pytest.mark.asyncio
 async def test_email_render_cell(ds_ct):
     await ds_ct.invoke_startup()