Add config option frontends_uri to specify allowed frontend addresses for Orion Web API

[notoraptor]

Description

Hi @bouthilx ! This is a pull request to wrap all changes related to CORS handling for Orion Web API. I will close other related pull requests so that we can focus only on this one.

This PR adds option frontends_uri to list allowed frontend addresses and add falcon-cors dependencies for PYPI (using original package) and conda (using conda package I built from PYPI package and uploaded on my anaconda repo)

Changes

• Re-add changes reverted from Revert "Add falcon-cors requirement to make orion server accept CORS requests" #792
• Add changes from Add channel notoraptor to find conda package falcon-cors when building conda package bouthilx/orion#4
  • Changes should fix Add falcon-cors to Orion's PYPI and conda dependencies #793
  • Changes should resolve issue from Add missing falcon-cors dependency for conda #780
• Add changes from Add configuration frontends to list allowed frontends for Orion server #782
  • Changes should fix Add a configuration to select frontend server accepted by orion serve #779

Checklist

Tests

• I added corresponding tests for bug fixes and new features. If possible, the tests fail without the changes
• All new and existing tests are passing ($ tox -e py38; replace 38 by your Python version if necessary)

Documentation

• I have updated the relevant documentation related to my changes

Quality

• I have read the CONTRIBUTING doc
• My commits messages follow this format
• My code follows the style guidelines ($ tox -e lint)

Further comments

Please include any additional information or comment that you feel will be helpful to the review of this pull request.

[bouthilx]

Thanks! Ideally the conda packaging of falcon-cors should be integrated in our packaging pipeline to make sure we update it properly over time. However we should not expect to much changes in falcon-cors since last updates were 2 years ago. That leads me to another question; Is it a good idea to depend on this package, which does not seam maintained anymore, to address security concerns? I'm not sure...

[notoraptor]

@bouthilx Indeed, it's an old package.

Maybe I could just copy the code (with citation) directly into orion, as it's a matter of 2 classes (CORS + CORSMiddleware), so that we won't need any dependency anymore?

[bouthilx]

For reference, after discussion with @notoraptor we decided to fork falcon-cors into @mila-iqia to maintain it ourselves. The code itself is not expected to evolve a lot since it is mostly just related to the CORS standard, but the tests may needs adjustments based on changes in falcon.testing.TestCase. We will also publish falcon-cors in the mila-iqia forge.

[notoraptor]

@bouthilx PR updated, and conda package falcon-cors copied into mila-iqia channel: https://anaconda.org/mila-iqia/falcon-cors

However, it seems I don't have rights on github mila-iqia organization to fork falcon-cors repo into.

[notoraptor]

falcon-cors is forked into mila-iqia @bouthilx ! https://github.com/mila-iqia/falcon-cors

[bouthilx]

All good for this PR then, thanks!