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   1  <?php
   2  /**
   3   * API for easily embedding rich media such as videos and images into content.
   4   *
   5   * @package WordPress
   6   * @subpackage Embed
   7   * @since 2.9.0
   8   */
   9  class WP_Embed {
  10      var $handlers = array();
  11      var $post_ID;
  12      var $usecache = true;
  13      var $linkifunknown = true;
  14  
  15      /**
  16       * Constructor
  17       */
  18  	function __construct() {
  19          // Hack to get the [embed] shortcode to run before wpautop()
  20          add_filter( 'the_content', array( $this, 'run_shortcode' ), 8 );
  21  
  22          // Shortcode placeholder for strip_shortcodes()
  23          add_shortcode( 'embed', '__return_false' );
  24  
  25          // Attempts to embed all URLs in a post
  26          add_filter( 'the_content', array( $this, 'autoembed' ), 8 );
  27  
  28          // When a post is saved, invalidate the oEmbed cache
  29          add_action( 'pre_post_update', array( $this, 'delete_oembed_caches' ) );
  30  
  31          // After a post is saved, cache oEmbed items via AJAX
  32          add_action( 'edit_form_advanced', array( $this, 'maybe_run_ajax_cache' ) );
  33      }
  34  
  35      /**
  36       * Process the [embed] shortcode.
  37       *
  38       * Since the [embed] shortcode needs to be run earlier than other shortcodes,
  39       * this function removes all existing shortcodes, registers the [embed] shortcode,
  40       * calls {@link do_shortcode()}, and then re-registers the old shortcodes.
  41       *
  42       * @uses $shortcode_tags
  43       * @uses remove_all_shortcodes()
  44       * @uses add_shortcode()
  45       * @uses do_shortcode()
  46       *
  47       * @param string $content Content to parse
  48       * @return string Content with shortcode parsed
  49       */
  50  	function run_shortcode( $content ) {
  51          global $shortcode_tags;
  52  
  53          // Back up current registered shortcodes and clear them all out
  54          $orig_shortcode_tags = $shortcode_tags;
  55          remove_all_shortcodes();
  56  
  57          add_shortcode( 'embed', array( $this, 'shortcode' ) );
  58  
  59          // Do the shortcode (only the [embed] one is registered)
  60          $content = do_shortcode( $content );
  61  
  62          // Put the original shortcodes back
  63          $shortcode_tags = $orig_shortcode_tags;
  64  
  65          return $content;
  66      }
  67  
  68      /**
  69       * If a post/page was saved, then output JavaScript to make
  70       * an AJAX request that will call WP_Embed::cache_oembed().
  71       */
  72  	function maybe_run_ajax_cache() {
  73          $post = get_post();
  74  
  75          if ( ! $post || empty($_GET['message']) || 1 != $_GET['message'] )
  76              return;
  77  
  78  ?>
  79  <script type="text/javascript">
  80  /* <![CDATA[ */
  81      jQuery(document).ready(function($){
  82          $.get("<?php echo admin_url( 'admin-ajax.php?action=oembed-cache&post=' . $post->ID, 'relative' ); ?>");
  83      });
  84  /* ]]> */
  85  </script>
  86  <?php
  87      }
  88  
  89      /**
  90       * Register an embed handler. Do not use this function directly, use {@link wp_embed_register_handler()} instead.
  91       * This function should probably also only be used for sites that do not support oEmbed.
  92       *
  93       * @param string $id An internal ID/name for the handler. Needs to be unique.
  94       * @param string $regex The regex that will be used to see if this handler should be used for a URL.
  95       * @param callback $callback The callback function that will be called if the regex is matched.
  96       * @param int $priority Optional. Used to specify the order in which the registered handlers will be tested (default: 10). Lower numbers correspond with earlier testing, and handlers with the same priority are tested in the order in which they were added to the action.
  97       */
  98  	function register_handler( $id, $regex, $callback, $priority = 10 ) {
  99          $this->handlers[$priority][$id] = array(
 100              'regex'    => $regex,
 101              'callback' => $callback,
 102          );
 103      }
 104  
 105      /**
 106       * Unregister a previously registered embed handler. Do not use this function directly, use {@link wp_embed_unregister_handler()} instead.
 107       *
 108       * @param string $id The handler ID that should be removed.
 109       * @param int $priority Optional. The priority of the handler to be removed (default: 10).
 110       */
 111  	function unregister_handler( $id, $priority = 10 ) {
 112          if ( isset($this->handlers[$priority][$id]) )
 113              unset($this->handlers[$priority][$id]);
 114      }
 115  
 116      /**
 117       * The {@link do_shortcode()} callback function.
 118       *
 119       * Attempts to convert a URL into embed HTML. Starts by checking the URL against the regex of the registered embed handlers.
 120       * If none of the regex matches and it's enabled, then the URL will be given to the {@link WP_oEmbed} class.
 121       *
 122       * @uses wp_oembed_get()
 123       * @uses wp_parse_args()
 124       * @uses wp_embed_defaults()
 125       * @uses WP_Embed::maybe_make_link()
 126       * @uses get_option()
 127       * @uses author_can()
 128       * @uses wp_cache_get()
 129       * @uses wp_cache_set()
 130       * @uses get_post_meta()
 131       * @uses update_post_meta()
 132       *
 133       * @param array $attr Shortcode attributes.
 134       * @param string $url The URL attempting to be embedded.
 135       * @return string The embed HTML on success, otherwise the original URL.
 136       */
 137  	function shortcode( $attr, $url = '' ) {
 138          $post = get_post();
 139  
 140          if ( empty( $url ) )
 141              return '';
 142  
 143          $rawattr = $attr;
 144          $attr = wp_parse_args( $attr, wp_embed_defaults() );
 145  
 146          // kses converts & into &amp; and we need to undo this
 147          // See http://core.trac.wordpress.org/ticket/11311
 148          $url = str_replace( '&amp;', '&', $url );
 149  
 150          // Look for known internal handlers
 151          ksort( $this->handlers );
 152          foreach ( $this->handlers as $priority => $handlers ) {
 153              foreach ( $handlers as $id => $handler ) {
 154                  if ( preg_match( $handler['regex'], $url, $matches ) && is_callable( $handler['callback'] ) ) {
 155                      if ( false !== $return = call_user_func( $handler['callback'], $matches, $attr, $url, $rawattr ) )
 156                          /**
 157                           * Filter the returned embed handler.
 158                           *
 159                           * @since 2.9.0
 160                           *
 161                           * @param mixed  $return The shortcode callback function to call.
 162                           * @param string $url    The attempted embed URL.
 163                           * @param array  $attr   An array of shortcode attributes.
 164                           */
 165                          return apply_filters( 'embed_handler_html', $return, $url, $attr );
 166                  }
 167              }
 168          }
 169  
 170          $post_ID = ( ! empty( $post->ID ) ) ? $post->ID : null;
 171          if ( ! empty( $this->post_ID ) ) // Potentially set by WP_Embed::cache_oembed()
 172              $post_ID = $this->post_ID;
 173  
 174          // Unknown URL format. Let oEmbed have a go.
 175          if ( $post_ID ) {
 176  
 177              // Check for a cached result (stored in the post meta)
 178              $cachekey = '_oembed_' . md5( $url . serialize( $attr ) );
 179              if ( $this->usecache ) {
 180                  $cache = get_post_meta( $post_ID, $cachekey, true );
 181  
 182                  // Failures are cached
 183                  if ( '{{unknown}}' === $cache )
 184                      return $this->maybe_make_link( $url );
 185  
 186                  if ( ! empty( $cache ) )
 187                      /**
 188                       * Filter the cached oEmbed HTML.
 189                       *
 190                       * @since 2.9.0
 191                       *
 192                       * @param mixed  $cache   The cached HTML result, stored in post meta.
 193                       * @param string $url     The attempted embed URL.
 194                       * @param array  $attr    An array of shortcode attributes.
 195                       * @param int    $post_ID Post ID.
 196                       */
 197                      return apply_filters( 'embed_oembed_html', $cache, $url, $attr, $post_ID );
 198              }
 199  
 200              /**
 201               * Filter whether to inspect the given URL for discoverable <link> tags.
 202               *
 203               * @see WP_oEmbed::discover()
 204               *
 205               * @param bool false Whether to enable <link> tag discovery. Default false.
 206               */
 207              $attr['discover'] = ( apply_filters( 'embed_oembed_discover', false ) && author_can( $post_ID, 'unfiltered_html' ) );
 208  
 209              // Use oEmbed to get the HTML
 210              $html = wp_oembed_get( $url, $attr );
 211  
 212              // Cache the result
 213              $cache = ( $html ) ? $html : '{{unknown}}';
 214              update_post_meta( $post_ID, $cachekey, $cache );
 215  
 216              // If there was a result, return it
 217              if ( $html ) {
 218                  /** This filter is documented in wp-includes/class-wp-embed.php */
 219                  return apply_filters( 'embed_oembed_html', $html, $url, $attr, $post_ID );
 220              }
 221          }
 222  
 223          // Still unknown
 224          return $this->maybe_make_link( $url );
 225      }
 226  
 227      /**
 228       * Delete all oEmbed caches.
 229       *
 230       * @param int $post_ID Post ID to delete the caches for.
 231       */
 232  	function delete_oembed_caches( $post_ID ) {
 233          $post_metas = get_post_custom_keys( $post_ID );
 234          if ( empty($post_metas) )
 235              return;
 236  
 237          foreach( $post_metas as $post_meta_key ) {
 238              if ( '_oembed_' == substr( $post_meta_key, 0, 8 ) )
 239                  delete_post_meta( $post_ID, $post_meta_key );
 240          }
 241      }
 242  
 243      /**
 244       * Triggers a caching of all oEmbed results.
 245       *
 246       * @param int $post_ID Post ID to do the caching for.
 247       */
 248  	function cache_oembed( $post_ID ) {
 249          $post = get_post( $post_ID );
 250  
 251          $post_types = array( 'post', 'page' );
 252          /**
 253           * Filter the array of post types to cache oEmbed results for.
 254           *
 255           * @since 2.9.0
 256           *
 257           * @param array $post_types Array of post types to cache oEmbed results for. Default 'post', 'page'.
 258           */
 259          if ( empty($post->ID) || !in_array( $post->post_type, apply_filters( 'embed_cache_oembed_types', $post_types ) ) )
 260              return;
 261  
 262          // Trigger a caching
 263          if ( !empty($post->post_content) ) {
 264              $this->post_ID = $post->ID;
 265              $this->usecache = false;
 266  
 267              $content = $this->run_shortcode( $post->post_content );
 268              $this->autoembed( $content );
 269  
 270              $this->usecache = true;
 271          }
 272      }
 273  
 274      /**
 275       * Passes any unlinked URLs that are on their own line to {@link WP_Embed::shortcode()} for potential embedding.
 276       *
 277       * @uses WP_Embed::autoembed_callback()
 278       *
 279       * @param string $content The content to be searched.
 280       * @return string Potentially modified $content.
 281       */
 282  	function autoembed( $content ) {
 283          return preg_replace_callback( '|^\s*(https?://[^\s"]+)\s*$|im', array( $this, 'autoembed_callback' ), $content );
 284      }
 285  
 286      /**
 287       * Callback function for {@link WP_Embed::autoembed()}.
 288       *
 289       * @uses WP_Embed::shortcode()
 290       *
 291       * @param array $match A regex match array.
 292       * @return string The embed HTML on success, otherwise the original URL.
 293       */
 294  	function autoembed_callback( $match ) {
 295          $oldval = $this->linkifunknown;
 296          $this->linkifunknown = false;
 297          $return = $this->shortcode( array(), $match[1] );
 298          $this->linkifunknown = $oldval;
 299  
 300          return "\n$return\n";
 301      }
 302  
 303      /**
 304       * Conditionally makes a hyperlink based on an internal class variable.
 305       *
 306       * @param string $url URL to potentially be linked.
 307       * @return string Linked URL or the original URL.
 308       */
 309  	function maybe_make_link( $url ) {
 310          $output = ( $this->linkifunknown ) ? '<a href="' . esc_url($url) . '">' . esc_html($url) . '</a>' : $url;
 311  
 312          /**
 313           * Filter the returned, maybe-linked embed URL.
 314           *
 315           * @since 2.9.0
 316           *
 317           * @param string $output The linked or original URL.
 318           * @param string $url    The original URL.
 319           */
 320          return apply_filters( 'embed_maybe_make_link', $output, $url );
 321      }
 322  }
 323  $GLOBALS['wp_embed'] = new WP_Embed();