When picking file from EQUELLA repository, an error message says "The source url does not match the sourcekey."

To replicate the error,

1. Setup a EQUELLA repository
2. Create a page in a course
3. In the tinymce editor, select "Image" button.
4. Search and select an image from EQUELLA repository.

A pop-up error box will show "The source url does not match the sourcekey."

This bug is introduced by the new sourcekey parameter for validating source URL.

To solve the error, /repository/equella/callback.php need to be updated as follows:

• After line 71, add

             $sourcekey=sha1($source.get_secret_key().sesskey());

• After line 81, add

             resource.sourcekey = "$sourcekey";