Add beta version of doc diff library for testing

[agjohnson]

Very slim chance this works as expected

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📚 Documentation previews 📚

• User's documentation (docs): https://docs--9546.org.readthedocs.build/en/9546/

• Developer's documentation (dev): https://dev--9546.org.readthedocs.build/en/9546/

[agjohnson]

Yeah, CORS error, about what I expected.

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://docs.readthedocs.io/en/latest/versions.html. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing).

Page that should have a diff: https://docs--9546.org.readthedocs.build/en/9546/versions.html

[humitos]

This works pretty nice! (I had to disable the CORS restriction in my browser, tho)

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I noticed that it detected a weird change in the table, tho. It seems that table was not changed in the PR.

[agjohnson]

I noticed that it detected a weird change in the table, tho

That is odd, the HTML is identical 🤔

[agjohnson]

I opened readthedocs/addons#93 to discuss CORS and authentication mitigation at a broad level.

[ericholscher]

This is wonderful! Excited to figure out the CORS issue, and have some of this magic in our PR's 🎉

[humitos]

@stsewd how hard would be to enable CORS for this particular case? I'd love to see this PR merged and in action for our repository at least.

[stsewd]

@humitos there is an issue related to this at https://github.com/readthedocs/readthedocs-corporate/issues/1482. We should be safe to allow cross site requests on .org, since everything is public, and we don't use cookies on the docs domains (we could even restrict this for domains that are valid on .org only).

[ericholscher]

We could use a CORS proxy for this. I already have one running in workers for WTD we could test against: https://cors.writethedocs.workers.dev/corsproxy/?apiurl=https://docs.readthedocs.io/en/stable/

[agjohnson]

[ericholscher]

Fancy :)

[humitos]

It works! 💪🏼

Example: https://docs--9546.org.readthedocs.build/en/9546/build-customization.html

[agjohnson]

Note, what we added was a hack. I'd wait to merge this until we have a proxy maintained on the RTD side.

[humitos]

I know that we have worked around on some CORS issues already. Are we ready to merge this PR and start using internally the doc-diff javascript library?

[ericholscher]

I'm 👍 on it! Dogfooding ftw.

[humitos]

OK, this is looking good so far:

I'm going to merge it and we can continue from there.

[ericholscher]

Nice.