Redirect paths from the notebooks route to the tree route if they are…

… directories

notebook/app.py

@@ -203,8 +203,16 @@ class NotebookHandler(NotebookBaseHandler):
     """A notebook page handler."""
 
     @web.authenticated
-    def get(self, path: str | None = None) -> t.Any:  # noqa: ARG002
-        """Get the notebook page."""
+    async def get(self, path: str = "") -> t.Any:
+        """Get the notebook page. Redirect if it's a directory."""
+        path = path.strip("/")
+        cm = self.contents_manager
+
+        if await ensure_async(cm.dir_exists(path=path)):
+            url = ujoin(self.base_url, "tree", url_escape(path))
+            self.log.debug("Redirecting %s to %s since path is a directory", self.request.path, url)
+            self.redirect(url)
+            return None
         tpl = self.render_template("notebooks.html", page_config=self.get_page_config())
         return self.write(tpl)
 

tests/test_app.py

@@ -3,7 +3,7 @@
 import pytest
 from tornado.httpclient import HTTPClientError
 
-from notebook.app import JupyterNotebookApp, TreeHandler
+from notebook.app import JupyterNotebookApp, NotebookHandler, TreeHandler
 
 
 @pytest.fixture()
@@ -32,6 +32,16 @@ async def test_notebook_handler(notebooks, jp_fetch):
         html = r.body.decode()
         assert "Jupyter Notebook" in html
 
+    redirected_url = None
+
+    def redirect(self, url):
+        nonlocal redirected_url
+        redirected_url = url
+
+    NotebookHandler.redirect = redirect
+    await jp_fetch("notebooks", "jlab_test_notebooks")
+    assert redirected_url == "/a%40b/tree/jlab_test_notebooks"
+
 
 async def test_tree_handler(notebooks, notebookapp, jp_fetch):
     app: JupyterNotebookApp = notebookapp