Fix double-prefixed export links with base_url

Use the router-stripped route_path when building request-derived export
URLs, so table, row, and query JSON/CSV links do not apply base_url twice.

Keep urls.path() behavior unchanged, and add coverage for both /prefix/
exports and a /data/ base_url with a data database.

Closes #2759

datasette/utils/__init__.py

@@ -837,7 +837,8 @@ def path_with_format(
     *, request=None, path=None, format=None, extra_qs=None, replace_format=None
 ):
     qs = extra_qs or {}
-    path = request.path if request else path
+    if path is None and request:
+        path = request.path
     if replace_format and path.endswith(f".{replace_format}"):
         path = path[: -(1 + len(replace_format))]
     if "." in path:

datasette/views/base.py

@@ -153,7 +153,13 @@ class BaseView:
         if self.has_json_alternate:
             alternate_url_json = self.ds.absolute_url(
                 request,
-                self.ds.urls.path(path_with_format(request=request, format="json")),
+                self.ds.urls.path(
+                    path_with_format(
+                        request=request,
+                        path=request.scope.get("route_path"),
+                        format="json",
+                    )
+                ),
             )
             template_context["alternate_url_json"] = alternate_url_json
             headers.update(
@@ -347,13 +353,21 @@ class DataView(BaseView):
                 if it_can_render:
                     renderers[key] = self.ds.urls.path(
                         path_with_format(
-                            request=request, format=key, extra_qs={**url_labels_extra}
+                            request=request,
+                            path=request.scope.get("route_path"),
+                            format=key,
+                            extra_qs={**url_labels_extra},
                         )
                     )
 
             url_csv_args = {"_size": "max", **url_labels_extra}
             url_csv = self.ds.urls.path(
-                path_with_format(request=request, format="csv", extra_qs=url_csv_args)
+                path_with_format(
+                    request=request,
+                    path=request.scope.get("route_path"),
+                    format="csv",
+                    extra_qs=url_csv_args,
+                )
             )
             url_csv_path = url_csv.split("?")[0]
             context = {

datasette/views/database.py

@@ -157,7 +157,13 @@ class DatabaseView(View):
         assert format_ == "html"
         alternate_url_json = datasette.absolute_url(
             request,
-            datasette.urls.path(path_with_format(request=request, format="json")),
+            datasette.urls.path(
+                path_with_format(
+                    request=request,
+                    path=request.scope.get("route_path"),
+                    format="json",
+                )
+            ),
         )
         templates = (f"database-{to_css_class(database)}.html", "database.html")
         environment = datasette.get_jinja_environment(request)
@@ -744,7 +750,13 @@ class QueryView(View):
             template = environment.select_template(templates)
             alternate_url_json = datasette.absolute_url(
                 request,
-                datasette.urls.path(path_with_format(request=request, format="json")),
+                datasette.urls.path(
+                    path_with_format(
+                        request=request,
+                        path=request.scope.get("route_path"),
+                        format="json",
+                    )
+                ),
             )
             data = {}
             headers.update(
@@ -776,7 +788,11 @@ class QueryView(View):
                 it_can_render = await await_me_maybe(it_can_render)
                 if it_can_render:
                     renderers[key] = datasette.urls.path(
-                        path_with_format(request=request, format=key)
+                        path_with_format(
+                            request=request,
+                            path=request.scope.get("route_path"),
+                            format=key,
+                        )
                     )
 
             allow_execute_sql = await datasette.allowed(
@@ -905,7 +921,10 @@ class QueryView(View):
                         renderers=renderers,
                         url_csv=datasette.urls.path(
                             path_with_format(
-                                request=request, format="csv", extra_qs={"_size": "max"}
+                                request=request,
+                                path=request.scope.get("route_path"),
+                                format="csv",
+                                extra_qs={"_size": "max"},
                             )
                         ),
                         show_hide_hidden=markupsafe.Markup(show_hide_hidden),

datasette/views/table.py

@@ -1072,7 +1072,13 @@ async def table_view_traced(datasette, request):
         template = environment.select_template(templates)
         alternate_url_json = datasette.absolute_url(
             request,
-            datasette.urls.path(path_with_format(request=request, format="json")),
+            datasette.urls.path(
+                path_with_format(
+                    request=request,
+                    path=request.scope.get("route_path"),
+                    format="json",
+                )
+            ),
         )
         headers.update(
             {
@@ -1878,7 +1884,10 @@ async def table_view_data(
             if it_can_render:
                 renderers[key] = datasette.urls.path(
                     path_with_format(
-                        request=request, format=key, extra_qs={**url_labels_extra}
+                        request=request,
+                        path=request.scope.get("route_path"),
+                        format=key,
+                        extra_qs={**url_labels_extra},
                     )
                 )
         return renderers
@@ -2042,7 +2051,12 @@ async def table_view_data(
             url_labels_extra = {"_labels": "on"}
         url_csv_args = {"_size": "max", **url_labels_extra}
         url_csv = datasette.urls.path(
-            path_with_format(request=request, format="csv", extra_qs=url_csv_args)
+            path_with_format(
+                request=request,
+                path=request.scope.get("route_path"),
+                format="csv",
+                extra_qs=url_csv_args,
+            )
         )
         url_csv_path = url_csv.split("?")[0]
         data.update(

tests/test_internals_urls.py

@@ -16,6 +16,8 @@ def ds():
         ("/prefix/", "/", "/prefix/"),
         ("/prefix/", "/foo", "/prefix/foo"),
         ("/prefix/", "foo", "/prefix/foo"),
+        ("/data/", "/data", "/data/data"),
+        ("/data/", "/data/foo", "/data/data/foo"),
     ],
 )
 def test_path(ds, base_url, path, expected):

tests/test_table_html.py

@@ -510,6 +510,57 @@ async def test_table_csv_json_export_interface(ds_client):
     ] == inputs
 
 
+def test_base_url_export_links_are_not_double_prefixed(app_client_base_url_prefix):
+    for path, expected_json, expected_csv in (
+        (
+            "/prefix/fixtures/simple_primary_key?id__gt=2",
+            "/prefix/fixtures/simple_primary_key.json?id__gt=2",
+            "/prefix/fixtures/simple_primary_key.csv?id__gt=2&_size=max",
+        ),
+        (
+            "/prefix/fixtures/simple_primary_key/1",
+            "/prefix/fixtures/simple_primary_key/1.json",
+            None,
+        ),
+        (
+            "/prefix/fixtures/-/query?sql=select+1",
+            "/prefix/fixtures/-/query.json?sql=select+1",
+            "/prefix/fixtures/-/query.csv?sql=select+1&_size=max",
+        ),
+    ):
+        response = app_client_base_url_prefix.get(path)
+        assert response.status_code == 200
+        soup = Soup(response.text, "html.parser")
+        export_links = soup.find("p", {"class": "export-links"}) or next(
+            p for p in soup.find_all("p") if "This data as" in p.get_text()
+        )
+        hrefs = [a["href"] for a in export_links.find_all("a", href=True)]
+        assert expected_json in hrefs
+        if expected_csv:
+            assert expected_csv in hrefs
+        assert not [href for href in hrefs if href.startswith("/prefix/prefix/")]
+        assert response.headers["link"] == (
+            f"<http://localhost{expected_json}>; "
+            'rel="alternate"; type="application/json+datasette"'
+        )
+
+
+def test_base_url_export_links_when_database_matches_prefix():
+    with make_app_client(settings={"base_url": "/data/"}, filename="data.db") as client:
+        response = client.get("/data/data/simple_primary_key?id__gt=2")
+        assert response.status_code == 200
+        export_links = Soup(response.text, "html.parser").find(
+            "p", {"class": "export-links"}
+        )
+        hrefs = [a["href"] for a in export_links.find_all("a", href=True)]
+        assert "/data/data/simple_primary_key.json?id__gt=2" in hrefs
+        assert "/data/data/simple_primary_key.csv?id__gt=2&_size=max" in hrefs
+        assert response.headers["link"] == (
+            "<http://localhost/data/data/simple_primary_key.json?id__gt=2>; "
+            'rel="alternate"; type="application/json+datasette"'
+        )
+
+
 @pytest.mark.asyncio
 async def test_csv_json_export_links_include_labels_if_foreign_keys(ds_client):
     response = await ds_client.get("/fixtures/facetable")

tests/test_utils.py

@@ -453,6 +453,12 @@ def test_path_with_format(path, format, extra_qs, expected):
     assert expected == actual
 
 
+def test_path_with_format_can_override_request_path():
+    request = Request.fake("/prefix/foo?x=1")
+    actual = utils.path_with_format(request=request, path="/foo", format="json")
+    assert "/foo.json?x=1" == actual
+
+
 @pytest.mark.parametrize(
     "bytes,expected",
     [