Update CORS allowed headers for compatibility w/ axios-cache-interceptor

[bradenmacdonald]

Summary

Fixes a CORS error seen by developers who run MFEs in dev mode on their host, alongside Tutor.

Description

In openedx/frontend-app-authoring#1209 , the version of axios-cache-interceptor used in the Course Authoring MFE was bumped from v0.28 to v1.6. The new setting cache.cacheTakeover which defaults to true is adding three new headers to the "runtime config" request that happens when the MFE starts up, and this is causing an error for those of us who run the MFE outside of a container.

This exact issue and the suggested fix are described in the linked documentation for cache.cacheTakeover:

cache.cacheTakeover (default true): you need to make sure Cache-Control, Pragma and Expires headers are included into your server’s Access-Control-Allow-Headers CORS configuration.

Supporting information

Discussed on Slack

Alternatives

I could make the changes for both cms and lms; currently I only modified LMS.

I could make the changes in Tutor or only in dev mode; I put them in lms/common

Testing instructions

1. Make sure course-authoring is bind-mounted so tutor doesn't run it:

   tutor mounts add /path/to/frontend-app-course-authoring
   

2. Start Tutor but not the MFE: tutor dev start lms cms mfe (we don't start course-authoring)
3. On your host, run git pull and npm install in the frontend-app-course-authoring folder.
4. On your host, start the MFE:

   APP_ID=course-authoring PUBLIC_PATH=/course-authoring/ MFE_CONFIG_API_URL='http://localhost:8000/api/mfe_config/v1' npm run start -- --host apps.local.overhang.io
   

   (or apps.local.edly.io if your Tutor instance is not as old as mine is)
5. Without this fix, you should see a CORE error when trying to access any part of course-authoring. With this fix, it should work.

Deadline

None

[openedx-webhooks]

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[robrap]

Only question is whether you'd want a unit test to ensure that the change doesn't get unintentionally lost.

[bradenmacdonald]

Thanks! I think it's fine for now without a test. If we later realize these headers are really important, we can add them to CMS too and add some tests. For now it only affects a few developers.

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[edx-pipeline-bot]

2U Release Notice: This PR has been deployed to the edX staging environment in preparation for a release to production.

[edx-pipeline-bot]

2U Release Notice: This PR has been deployed to the edX production environment.

[edx-pipeline-bot]

2U Release Notice: This PR has been deployed to the edX production environment.