[wp-trac] [WordPress Trac] #38907: Add `path_is_absolute` filter.

[WordPress Trac]

#38907: Add `path_is_absolute` filter.
-----------------------------+-----------------------------
 Reporter:  tmatsuo          |      Owner:
     Type:  feature request  |     Status:  new
 Priority:  normal           |  Milestone:  Awaiting Review
Component:  Media            |    Version:  4.6.1
 Severity:  normal           |   Keywords:
  Focuses:                   |
-----------------------------+-----------------------------
 so that plugin developers can easily add media functionalities with stream
 wrappers.


 The path_is_absolute function will be updated to:
 {{{#!php
 <?php
 function path_is_absolute( $path ) {
     /*
      * First apply a filter and see the result
      */
     if ( apply_filters('path_is_absolute', $path) == true )
         return true;

     /*
      * This is definitive if true but fails if $path does not exist or
 contains
      * a symbolic link.
      */
     if ( realpath($path) == $path )
         return true;

     if ( strlen($path) == 0 || $path[0] == '.' )
         return false;

     // Windows allows absolute paths like this.
     if ( preg_match('#^[a-zA-Z]:\\\\#', $path) )
         return true;

     // A path starting with / or \ is absolute; anything else is relative.
     return ( $path[0] == '/' || $path[0] == '\\' );
 }
 }}}


 Background:

 I'm developing a plugin for uploading media files to Google Cloud Storage,
 using Google Cloud Storage stream wrapper (gs:// path).

 It's easy to use the `upload_dir` to achieve it, but when it comes to
 deleting media files, there is a problem.

 In `wp-includes/post.php`, there are some code to delete related files
 when you delete an uploaded media file:

 {{{#!php
 <?php
         // Remove intermediate and backup images if there are any.
         if ( isset( $meta['sizes'] ) && is_array( $meta['sizes'] ) ) {
                 foreach ( $meta['sizes'] as $size => $sizeinfo ) {
                         $intermediate_file = str_replace( basename( $file
 ), $sizeinfo['file'], $file );
                         /** This filter is documented in wp-
 includes/functions.php */
                         $intermediate_file = apply_filters(
 'wp_delete_file', $intermediate_file );
                         @ unlink( path_join( $uploadpath['basedir'],
 $intermediate_file ) );
                 }
         }
 }}}

 When we replace directories with `upload_dir` filter, the values of
 `$uploadpath['basedir']` and $intermediate_file are:

 {{{#!php
 <?php
 $uploadpath['basedir']; // gs://bucket_name/1/
 $intermediate_file; // gs://bucket_name/1/2016/11/old-electrical-panel-
 150x150.jpg
 }}}

 So the path_join now returns something like:
 `gs://bucket_name/1/gs://bucket_name/1/2016/11/old-electrical-panel-
 150x150.jpg` because the file path is not considered as absolute. If we
 can customize the return value of `path_is_absolute`, then the return
 value of `path_join` will be something like `gs://bucket_name/1/2016/11
 /old-electrical-panel-150x150.jpg` and the media editor correctly unlink
 the files.


 I'd appreciate it if you could consider adding this filter.
 Of course, let me know if there are better solutions.

 Thanks,

--
Ticket URL: <https://core.trac.wordpress.org/ticket/38907>
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