Voila: WARNING: Blocking Cross Origin WebSocket Attempt

[fleimgruber]

Given a voila notebook hosted via Nginx as described in https://voila.readthedocs.io/en/stable/deploy.html, Voila gives a warning of

May 20 09:24:47 vh1046571 voila.sh[120114]: [Voila] Using /tmp to store connection files
May 20 09:24:47 vh1046571 voila.sh[120114]: [Voila] Storing connection files in /tmp/voila_0cma0_p9.
May 20 09:24:47 vh1046571 voila.sh[120114]: [Voila] Serving static files from /home/user/miniconda3/envs/the_project/lib/python3.7/site-packages/voila/static.
May 20 09:24:47 vh1046571 voila.sh[120114]: [Voila] Voila is running at:
May 20 09:24:47 vh1046571 voila.sh[120114]: http://localhost:8866/
May 20 09:24:58 vh1046571 voila.sh[120114]: [Voila] WARNING | Notebook main_notebook.ipynb is not trusted
May 20 09:24:58 vh1046571 voila.sh[120114]: [Voila] Kernel started: ef289c80-7f6f-4baa-ae44-62f95962ae03
May 20 09:25:06 vh1046571 voila.sh[120114]: [Voila] WARNING | Blocking Cross Origin WebSocket Attempt.  Origin: http://my-site.eu, Host: my-site.eu:80
May 20 09:25:06 vh1046571 voila.sh[120114]: WARNING:tornado.access:403 GET /api/kernels/ef289c80-7f6f-4baa-ae44-62f95962ae03/channels?session_id=4301d7ea-f90f-45e3-a6ce-b56fff0cf5ff (::1) 7.24ms
May 20 09:25:07 vh1046571 voila.sh[120114]: [Voila] WARNING | Replacing stale connection: ef289c80-7f6f-4baa-ae44-62f95962ae03:4301d7ea-f90f-45e3-a6ce-b56fff0cf5ff

and no results are shown in the client browser (only "Executing cells") in an otherwise working setup. I tried to follow https://github.com/jupyter/jupyter/issues/232 with

c.NotebookApp.allow_origin = '*'

in ~/.jupyter/jupyter_notebook_config.py and /etc/jupyter/jupyter_notebook_config.py as well as .../etc/jupyter/nbconfig/notebook.d/voila.json but without luck.

[davidbrochart]

Could you try passing the following settings to Tornado?

"--Voila.tornado_settings={'headers':{'Content-Security-Policy':\"frame-ancestors 'self' " + server_address + "\"}}"

[fleimgruber]

Thanks for the hint, I succeeded with --Voila.tornado_settings="{'allow_origin': '*'}". I could not get your example to work via CLI as I did not manage to get the string quoting right. Is there another place to put the exact string you mentioned?

The 'tornado_settings' trait of a Voila instance must be a dict, but a value of class 'str'  (i.e. '{headers:{Content-Security-Policy:"frame-ancestors') was specified.

[davidbrochart]

Yes from the CLI you need to add quotes. That should work:

voila --Voila.tornado_settings="{'headers':{'Content-Security-Policy':\"frame-ancestors 'self' http://my-site.eu\"}}"

[fleimgruber]

Yes, now voila does not complain anymore, but I still get the same Cross Origin Warning. Maybe this has to do with my specific nginx config or I am missing something else, but I won't test this further as the allow_origin approach solved it for me. Thanks again for the hint!

[luiztauffer]

Yes from the CLI you need to add quotes. That should work:

voila --Voila.tornado_settings="{'headers':{'Content-Security-Policy':\"frame-ancestors 'self' http://my-site.eu\"}}"

Thank you both for the solutions, I'd like to leave it here in case someone needs, this worked for me (on Powershell):

voila --Voila.tornado_settings="{'headers':{'Content-Security-Policy': 'frame-ancestors http://localhost:8000'}}"

The http://localhost:8000 is because the iframe is from a Django app also running locally, you should substitute for your own website address

[femiir]

I am having the same issue using Heroku to deploy below is my procfile please help me out
_web: voila --port=$PORT --Voila.tornado_settings="{'headers':{'Content-Security-Policy':\"frame-ancestors 'self' https://gismapdev.herokuapp.com/\"}}"--strip_sources=True --enable_nbextensions=True --MappingKernelManager.cull_interval=60 --MappingKernelManager.cull_idle_timeout=120 notebooks/gis.ipynb_

[femiir]

this worked for me

web: voila --Voila.tornado_settings='{"headers":{"Content-Security-Policy":"frame-ancestors self *" }}' --port=$PORT --no-browser --strip_sources=True --enable_nbextensions=True --MappingKernelManager.cull_interval=60 --MappingKernelManager.cull_idle_timeout=120 notebooks/gis.ipy

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