Protected Media Files/Images not working on WPEngine

[brianhogg]

Reproduction Steps

1. Create a quiz for a course
2. Add a "picture choice" question and upload two new images

Expected Behavior

Image thumbnail appears, and is visible in the quiz

Actual Behavior

Image appears broken. It's a 301 redirect to the homepage instead of showing the image.

Note that I got requests with ?llms_media_id=... excluded from cache. In incognito it will show the "file not found" error, but will not load when logged in as admin.

[brianhogg]

The following snippet should resolve:

add_filter( 'llms_media_serve_method', function( $method ) {
   return LLMS_Media_Protector::SERVE_READ_FILE;
}, 10, 1 );

Ideally WPEngine would not redirect when the header is sent by the server to directly serve it, as it did before.

If we need to serve files this way we can check for WPE and automatically apply this serve method.