Nested Shortcode Inside [caption] Doesn’t Process

3 comments

1. There is a hook inside the caption shortcode that will allow you to hijack the whole thing. Most of the following is copied from the Core img_caption_shortcode function.

   function nested_img_caption_shortcode($nada, $attr, $content = null) {
   
     extract(
       shortcode_atts(
         array(
         'id'    => '',
         'align' => 'alignnone',
         'width' => '',
         'caption' => ''
         ), 
         $attr, 
         'caption'
       )
     );
   
     $caption = do_shortcode($caption); // process nested shortcodes
   
     if ( 1 > (int) $width || empty($caption) )
             return $content;
   
     if ( $id ) $id = 'id="' . esc_attr($id) . '" ';
   
     return '<div ' . $id . 'class="wp-caption ' . esc_attr($align) . '" style="width: ' . (10 + (int) $width) . 'px">'
     . do_shortcode( $content ) . '<p class="wp-caption-text">' . $caption . '</p></div>';
   }
   add_filter('img_caption_shortcode', 'nested_img_caption_shortcode', 1, 3);
   

2. The latest versions of WP have really improved the filterability of caption arguments, so I think this new answer will have the smallest footprint and safest operation.

   What we need to do is directly filter $atts['caption'] during shortcode_atts() for the [caption] shortcode. We can do this with the shortcode_atts_caption filter which only affects the caption shortcode.

   As a bonus I added a commented-out line that will test the caption for a specific shortcode before running do_shortcode(). This is useful if you only want to enable a particular shortcode in captions (I use it to enable only the Shortcode Shortcode). Careful though: do_shortcode() will process all shortcodes, not just the one you tested for.

   /**
    * Filter Caption shortcode attributes to enable the [shortcode] shortcode inside caption text
    * 
    * WP doesn't run do_shortcode on the 'caption' text value parsed out of [caption], which means
    * the [shortcode] shortcode doesn't work. 
    * 
    * @param array $out atts array as determined by WP to be returned after filtering
    * @param array $pairs 
    * @param array $atts
    * @return filtered $out atts
    */
    function wpse_113416_filter_shortcode_atts_caption($out, $pairs, $atts) {
       // OPTIONAL: Look for a specific shortcode before running do_shortcode
       // if (has_shortcode($out['caption'], 'shortcode_to_look_for')) 
           $out['caption'] = do_shortcode($out['caption']);
   
       return $out;
   }
   add_filter('shortcode_atts_caption', 'wpse_113416_filter_shortcode_atts_caption', 10, 3);
   

3. Using latest function has_shortcode() introduced on v3.6

   add_filter( 'the_content', 'process_wp_caption_shortcodes' ); // hook it late
   
       function process_wp_caption_shortcodes( $content ){
           if( !function_exists    ( 'has_shortcode' ) )   // no luck for user using older versions :)
               return $content;
   
           if( has_shortcode( get_the_content(), 'caption' ) ){ // check with raw content
               // caption exists on the current post
               $content = do_shortcode( $content );
           }
   
           return $content;
       }
   

   This solution can be used on any third party shotcode that didn’t implemented nested shortcode support.

   Any better solution welcomed!

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