_wp_preview_post_thumbnail_filter

Filters post thumbnail lookup to set the post thumbnail.

Description

(null|array) _wp_preview_post_thumbnail_filter( (null|array|string) $value, (int) $post_id, (string) $meta_key ); 

Returns (null|array)

The default return value or the post thumbnail meta array.

Parameters (3)

0. $value (null|array|string)
The value to return - a single metadata value, or an array of values.
1. $post_id (int)
The post id.
2. $meta_key (string)
The meta key.

Usage

  1. if ( !function_exists( '_wp_preview_post_thumbnail_filter' ) ) { 
  2.     require_once ABSPATH . WPINC . '/revision.php'; 
  3. } 
  4.   
  5. // The value to return - a single metadata value, or an array of values. 
  6. $value = null; 
  7.   
  8. // The post id. 
  9. $post_id = -1; 
  10.   
  11. // The meta key. 
  12. $meta_key = ''; 
  13.   
  14. // NOTICE! Understand what this does before running. 
  15. $result = _wp_preview_post_thumbnail_filter($value, $post_id, $meta_key); 
  16.     

Defined (1)

The function is defined in the following location(s).

/wp-includes/revision.php  
  1. function _wp_preview_post_thumbnail_filter( $value, $post_id, $meta_key ) { 
  2.     if ( ! $post = get_post() ) { 
  3.         return $value; 
  4.     } 
  5.  
  6.     if ( empty( $_REQUEST['_thumbnail_id'] ) || 
  7.          empty( $_REQUEST['preview_id'] ) || 
  8.          $post->ID != $post_id || 
  9.          '_thumbnail_id' != $meta_key || 
  10.          'revision' == $post->post_type || 
  11.          $post_id != $_REQUEST['preview_id'] 
  12.  ) { 
  13.         return $value; 
  14.     } 
  15.  
  16.     $thumbnail_id = intval( $_REQUEST['_thumbnail_id'] ); 
  17.     if ( $thumbnail_id <= 0 ) { 
  18.         return ''; 
  19.     } 
  20.  
  21.     return strval( $thumbnail_id ); 
  22. }