Absolute path for oembed iframe

If somebody only needs the change to absolute oembed path. We made only this change, see patch attached.

> Isn't this just a bug in the decoupled application? It's the responsibility of any decoupled application to transform relative URLs?

No, I think this is at least a DX issue. When CKeditor is used to embed a remote media, the iframe is embedded in the body of a long text. For most front end applications, sure, they can add a domain to the URL that output by Media OEmbed, but that means the front end needs to parse the body of the text.

For few frontend apps, multiple Drupal backends can be connected at the same time, therefore, the frontend would have a little bit more logic to write when prefixing a domain.

Proposed solution: And a checkbox somewhere to allow Media OEmbed to output absolute URLs when checked, and default to relative path for backward compatibility

I could reproduce this situation when testing Drupal in a subdirectory (ie:https://localhost/subdirectory).

We are trying to convert DrupalCI to GitlabCI in this issue: #3375827: Investigate tests failures →

One of the errors we were getting was in "MediaSourceOEmbedVideoTest"
* Job: https://git.drupalcode.org/project/gitlab_ci_testbed_for_drupal_core/-/j...
* Error: ElementNotFoundException: Element matching css "iframe.media-oembed-content" not found.

Upon investigation, this was due to having "/subdirectory/media/oembed?..." in the src attribute (note the starting "/"), but when prepending the base path, then "https://localhost/subdirectory/subdirectory/media/oembed?..." doesn't exist.

The fix:
* Pretty much the same as #14 (setting the value of the URL to absolute).
* See the second change here: https://git.drupalcode.org/project/gitlab_ci_testbed_for_drupal_core/-/c...
* Job: https://git.drupalcode.org/project/gitlab_ci_testbed_for_drupal_core/-/j... . See how the "MediaSourceOEmbedVideoTest" is gone.

I think #14 is the cleaner and easier solution, with no UI changes needed, but the suggested MR would also solve the issue.

See my previous comment for further context as this seems to be an issue as well in installations running in a subdirectory.

I've going to set this issue as "Need review" with the suggested fix in #14.

Believe the issue summary should be updated if the solution for #14 is the path forward. Will also needed test coverage.

This is blocking gitlab CI.

Updated slightly the issue description to match the suggested fix.

Given this fails on gitlab ci that will be plenty of implicit test coverage so happy to add explicit coverage in a follow-up.

Opened 📌 Add tests for oembed iframe absolute Active

Committed 05e455e and pushed to 11.x. Thanks!

The issue summary was updated a bit in #22

Automatically closed - issue fixed for 2 weeks with no activity.