这项任务并不像乍一看那么容易。主要问题是，您可以定义自己的[gallery] 快捷编码并简单地覆盖默认值。事实上，这正是一些主题所做的（怪你们这些最早的作者！）。在这种情况下，只需post_gallery 不会在所有情况下都起作用。

的缺点post_gallery

的缺点the_content

那么现在该怎么办呢？容易的与交互global $shortcode_tags. 它将回调作为第二个参数，因此实际上不太难确定我们是哪种情况。然后我们可以简单地按需切换。这样，我们在可靠性和性能之间取得了良好的平衡。

构建一个基本插件abstract 类（必须extend为了工作）。child类中需要定义三件事：

• $part - 要检索的零件$type - 您需要的匹配类型。有效的是digit/alphanumeric/alpha
• process_atts() - 处理输出的方法-无论您想对结果做什么，只需通过FTP将其上载到插件文件夹并激活即可。

  <?php
  /** Plugin Name: (#70451) »kaiser« Get Gallery attributes (Base) */
  if ( ! class_exists( \'wpse70451_extract_gallery_atts\' ) )
  {
  
  abstract class wpse70451_extract_gallery_atts
  {
      public $atts  = array();
  
      public $error;
  
      // Must get defined in extending class
      public $part;
      public $type;
  
      public static function init()
      {
          is_null( self :: $instance ) AND self :: $instance = new self;
          return self :: $instance;
      }
  
      public function __construct()
      {
          ! isset( $this->part ) AND new WP_Error();
  
          add_action( \'loop_start\', array( $this, \'error_handler\' ) );
  
          // The value of the array is the callback fn name
          // If it\'s the default, then we\'re on the safe side,
          // as the core fn is no pluggable and can\'t get overridden.
          if ( \'gallery_shortcode\' === $GLOBALS[\'shortcode_tags\'] )
          {
              add_filter( \'post_gallery\', array( $this, \'get_gallery_atts\' ), 0, 2 );
          }
          // Else we have to go with a slower regex
          else
          {
              add_filter( \'the_content\', array( $this, \'get_gallery_ids\' ), 0 );
          }
      }
  
      public function error_handler()
      {
          if (
              ! in_array(
                   $this->type
                  ,array(
                       \'digit\'
                      ,\'alphanumeric\'
                      ,\'alpha\'
                   )
              )
              OR ! empty( $this->type )
          )
              return new WP_Error( 
                   \'invalid_type\'
                  ,__( \'Invalid type set.\', \'wpse70451_textdomain\' )
                  ,__FILE__
              );
      }
  
      public function __toString()
      {
          $is_error = $this->error;
  
          if ( ! is_wp_error( $is_error ) )
              return;
  
          // No error message for Guests or Subscribers
          // Assuming that no one has activated caching plugins when debugging
          // and not set WP_DEBUG to TRUE on a live site
          if ( 
              ! is_user_logged_in()
              AND ! current_user_can( \'edit_posts\' ) 
              AND ( ! defined( \'WP_DEBUG\' ) OR ! WP_DEBUG )
          )
              return \'\';
  
          // Error output for development
          return "{$is_error->get_error_message( \'invalid_type\' )}: {$is_error->get_error_data()}";
      }
  
      public function get_gallery_ids( $content )
      {
          $pattern = get_shortcode_regex( $content );
          preg_match_all( "/{$pattern}/s", $content, $matches );
          $atts = explode( " ", array_shift( $matches[3] ) );
          foreach ( $atts as $att )
          {
              if ( strstr( $att, $this->part ) )
                  break;
          }
          preg_match_all( $this->get_regex( $this->type ), trim( $att ), $atts );
          $this->atts = array_filter( $atts );
  
          return $content;
      }
  
      // Build pattern
      public function get_regex( $type )
      {
          switch ( $type )
          {
              case \'digit\' :
                  $pattern_atts = \'/(\\d*)/\';
                  break;
  
              case \'alphanumeric\' :
                  $pattern_atts = \'/([A-Za-z0-9]*)/\';
                  break;
  
              case \'alpha\' :
                  $pattern_atts = \'/([A-Za-z]*)/\';
                  break;
  
              default :
                  // Add a method name `get_pattern()` to the extending class
                  // to work with a custom regex pattern.
                  if (  method_exists( $this, \'get_pattern\' ) )
                  {
                      $pattern_atts = $this->get_pattern();
                      break;
                  }
                  $pattern_atts = $this->get_regex( \'alphanumeric\' );
                  break;
          }
  
          return $pattern_atts;
      }
  
      public function get_gallery_atts( $content, $atts )
      {
          $this->atts = $atts[ $this->part ];
  
          // Allow overrides to trigger
          // at this point we already got what we need
          return $content;
      }
  
      // Must get defined in extending class
      public abstract function process_atts() {}
  } // END Class
  
  } // endif;
  

  处理一项任务，获得一个子项，在这里您可以看到实际的处理插件。首先，它将自己静态地挂接到init 钩住然后跑动父母__construct() 方法检索属性。

  然后需要定义要检索的属性（请参见类属性$part 和$type, 已默认为您要求的内容）。

  你需要做的最后两个决定是

  我想对结果做什么？看见process_atts()__construct() 在哪里process_atts() 被钩住了

  如果需要自定义正则表达式，只需添加一个名为get_regex() 到您的扩展类和return 您的自定义图案。然后设置$type 收件人和空字符串\'\' 你已经准备好了。

  <?php
  /** Plugin Name: (#70451) »kaiser« Get Gallery excludes */
  
  if ( ! class_exists( \'wpse70451_extract_gallery_excludes\' ) )
  {
      add_action( \'init\', array( \'wpse70451_extract_gallery_excludes\', \'init\' ) );
  
  final class wpse70451_extract_gallery_excludes extends wpse70451_extract_gallery_atts
  {
      public static $instance;
  
      public $part = \'exclude\';
  
      public $type = \'digit\';
  
      public static function init()
      {
          is_null( self :: $instance ) AND self :: $instance = new self;
          return self :: $instance;
      }
  
      public function __construct()
      {
          parent :: __construct();
  
          // Example hook: `loop_end`
          add_action( \'loop_end\', array( $this, \'process_atts\' ) );
      }
  
      public function process_atts()
      {
          $markup = \'\';
          // Do something with $this->atts;
          return print $markup;
      }
  } // END Class
  
  } // endif;
  

  更改您需要的内容，然后再次更改：只需通过FTP将此内容上载到您的插件文件夹并激活即可。

如果还需要在同一页上显示内容，那么使用post_gallery 滤器那么你就不需要任何正则表达式了

add_filter(\'post_gallery\', \'gallery_shortcode_excludes\', 10, 2);
function gallery_shortcode_excludes($content, $attr) {
    $excludes = $attr[\'excludes\'];
    // maybe also save it in some global/class/static variable

    //  return empty string to let wordpress continue to the shortcode output
    return \'\';
}