Handle trailing slashes in rest_preload_api_request

[spacedmonkey]

When passing a path to rest_preload_api_request that ends in query string, ensure that the parsed path also is untrailingslashit. Follow up to #51636

[antonvlasenko]

I'm working on a patch for this issue.

Trac ticket: https://core.trac.wordpress.org/ticket/57048

[antonvlasenko]

The ​proposed PR updates the rest_preload_api_request function to remove trailing slashes from path parth of the request when preloading data for a specified REST API path.

Before patch:
Preloading /wp/v2/types//?media// would return an array with preloaded data keyed as /wp/v2/types//?media. Only slashes at the end of the path were removed.

After patch:
The path would be /wp/v2/types?media.

Steps to test this PR:

1. Login to the admin panel.
2. Edit an existing post or create a new one and then click Edit.
3. Open the dev tools, inspect the source code of the page. You should see a call to the wp.apiFetch.createPreloadingMiddleware() function and the preloaded data passed as an argument of that function. Typical preloaded requests are:
   • /wp/v2/types?context=view
   • /wp/v2/taxonomies?context=view
   • /wp/v2/blocks?context=edit&per_page=-1
   • /wp/v2/posts/<post-ID>?context=edit
   • /wp/v2/types/post?context=edit
   • /wp/v2/settings

[spacedmonkey]

Me and @swissspidy came across this issue while working web stories together. We patched it in our own code. ​Here is our version of this function.

I can't remember now how we fixed this issue, but look at the git history.

[antonvlasenko]

Replying to spacedmonkey:

Me and @swissspidy came across this issue while working web stories together. We patched it in our own code. ​Here is our version of this function.

I can't remember now how we fixed this issue, but look at the git history.

Thank you for the hint, @spacedmonkey.
I believe this is the commit that addresses the issue in your version of the function: ​https://github.com/GoogleForCreators/web-stories-wp/commit/a7f4977f74d24f73c0a72d23501f6a1eb7ac9337#diff-e38e7938d6df1990969cd7d147a8d590b359fa3a96a33802c85aa5723abf0223R188

The ​proposed solution appears to not only resolve the issue you mentioned, but also correct the key at which preloaded data is stored (within the context of array_reduce()).

[spacedmonkey]

I have approved the PR for this change. Looks good to me. I have marked this ticket as commit. Take it away @swissspidy

[swissspidy]

In 59457:

REST API: Remove trailing slashes when preloading requests and there is a query string.

Follow-up to [51648], see #51636.

Props antonvlasenko, swissspidy, spacedmonkey.
Fixes #57048.

Committed in https://core.trac.wordpress.org/changeset/59457