fix: add configuration to enable correct redirect_uri

[mariajgrimaldi]

Description

This PR adds a configuration that enables the service provider (superset) to build the redirect_uri correctly matching the one created on the LMS site (identify provider).

For more information on this solution, please check these superset configurations: https://github.com/apache/superset/blob/master/superset/config.py#L273-L277

This PR solves #30

How to test

In a production environment (using https):

1. Install this branch: pip install git+https://github.com/eduNEXT/tutor-contrib-superset.git@MJG/redirect-uri-fix
2. tutor config save
3. tutor local start -d
4. Now, try login in to superset:
   
   Check the redirect_uri has the correct schema.

References

dpgaspar/Flask-AppBuilder#1666
apache/superset#8117
apache/airflow#17536 (comment)

[openedx-webhooks]

Thanks for the pull request, @mariajgrimaldi! Please note that it may take us up to several weeks or months to complete a review and merge your PR.

Feel free to add as much of the following information to the ticket as you can:

• supporting documentation
• Open edX discussion forum threads
• timeline information ("this must be merged by XX date", and why that is)
• partner information ("this is a course on edx.org")
• any other information that can help Product understand the context for the PR

All technical communication about the code itself will be done via the GitHub pull request interface. As a reminder, our process documentation is here.

Please let us know once your PR is ready for our review and all tests are green.

[itsjeyd]

label: core contributor

[itsjeyd]

@mariajgrimaldi Thanks for these changes! Let us know when they're ready for review.

[mariajgrimaldi]

Thanks! This is ready for review :)

[bmtcril]

As written this will overwrite the FEATURE_FLAGS from above, but I think this is a big enough change that we either want it on or off since it's not really related to HTTPS. Is there a plugin needed for the proxy fix?

[mariajgrimaldi]

I tested this without the override and I think it works. So we're good. Now, regarding the https issue, I'm no expert so I'll go with what you suggest. Our setups (docker-compose, k8s) are behind a proxy (caddy, a lb) so we needed the change in both cases. Maybe someone won't. Should we use something like SUPERSET_ENABLE_PROXY_FIX?

Is there a plugin needed for the proxy fix?

No, this is part of the superset config: https://github.com/apache/superset/blob/master/superset/config.py#L273-L277

[bmtcril]

We should probably make it a flag, sadly. For instance I think that running tutor dev doesn't use the caddy proxy. Otherwise looks good!

[mariajgrimaldi]

When running tutor dev the setting ENABLE_HTTPS should be False so we're good as it is right?

[mariajgrimaldi]

Sorry. I'll follow these changes instead:

{% if not ENABLE_WEB_PROXY %}
# Caddy is running behind a proxy: Superset needs to handle x-forwarded-* headers
# https://flask.palletsprojects.com/en/latest/deploying/proxy_fix/
ENABLE_PROXY_FIX = True
{% endif %}

From the tutor-cairn plugin

[openedx-webhooks]

@mariajgrimaldi 🎉 Your pull request was merged! Please take a moment to answer a two question survey so we can improve your experience in the future.