Unable to Navigate Notebooks via URL: 'Path Not Found' Error

[Guillaume Nadrault]

Description

When attempting to open a specific notebook in JupyterLab using the file path URL (e.g., http://127.0.0.1:8888/lab/tree/work/my_notebook.ipynb), a popup with the error message "Path Not Found" appears. Consequently, the notebook fails to open.

Reproduce

1. Start an instance of JupyterLab, I use the docker image jupyter/scipy-notebook:lab-4.0.7
2. Create a new notebook
3. Navigate to JupyterLab with the URL (e.g., http://127.0.0.1:8888/lab/tre) providing a bad path. Observe the error message "Path Not Found" is displayed.
4. Attempt to navigate to the previously created notebook using the URL (e.g., http://127.0.0.1:8888/lab/tree/work/my_notebook.ipynb). Notice that the same "Path Not Found" error persists, making navigation to the notebook with the URL impossible.

Expected behavior

After providing a valid path in the URL, such as the path of a previously created notebook, the user should be able to navigate to the notebook without encountering a "Path Not Found" error.

Context

• Operating System and version: Windows 10, WSL Ubuntu 22.04, Docker Desktop
• Browser and version: Chrome 120
• JupyterLab version: version 4.0.7, using jupyter/scipy-notebook:lab-4.0.7 docker image

Command Line Output

No error message in the output

Browser Output

Showing error: {message: 'The path: /lab/tre was not found. JupyterLab redirected to: /'}message: "The path: /lab/tre was not found. JupyterLab redirected to: /"[[Prototype]]: Object

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[Jason Weill]

This is a duplicate of jupyterlab/jupyterlab#12768, but I'm going to leave it open, because even though the JupyterLab issue was opened first, the problem is almost certainly in this regular expression in JupyterLab Server:

jupyterlab_server/jupyterlab_server/handlers.py

Lines 33 to 35 in 8b8182d

 MASTER_URL_PATTERN = ( 
     r"/(?P<mode>{}|doc)(?P<workspace>/workspaces/[a-zA-Z0-9\-\_]+)?(?P<tree>/tree/.*)?" 
 ) 

In short, this does not capture solely valid URLs, such as those starting with /lab/tree. We need to intercept malformed paths after /lab/ to prevent this from occurring.

[Vishnutheep B]

Hi @JasonWeill, this above issue is because of directly referencing the dictionary object instead of creating a copy in Python. This leads to unintended shared state, where modifications made to the dictionary in one part of the code affect other references to the same dictionary object.

jupyterlab_server/jupyterlab_server/handlers.py

Line 182 in 8b8182d

 page_config = super().get_page_config() 

This makes a direct access to the page_config dictionary object, meaning that appending the notFoundUrl to this page_config persists throughout the instance. As a consequence, accessing the correct URL after this operation continues to trigger the same error mentioning the same path which is captured while accessing the wrong path.

jupyterlab_server/jupyterlab_server/handlers.py

Line 183 in 8b8182d

 page_config["notFoundUrl"] = self.request.path 

So, creating a shallow copy of the object fixes this issue.👇

jupyterlab_server/jupyterlab_server/handlers.py

Line 182 in 3be24ab

 page_config = super().get_page_config().copy() 

I have raised a PR for this, please have a look into it.