WP_Embed

9#[AllowDynamicProperties]10class WP_Embed {11	public $handlers = array();12	public $post_ID;13	public $usecache      = true;14	public $linkifunknown = true;15	public $last_attr     = array();16	public $last_url      = '';17 18	/**19	 * When a URL cannot be embedded, return false instead of returning a link20	 * or the URL.21	 *22	 * Bypasses the {@see 'embed_maybe_make_link'} filter.23	 *24	 * @var bool25	 */26	public $return_false_on_fail = false;27 28	/**29	 * Constructor30	 */31	public function __construct() {32		// Hack to get the [embed] shortcode to run before wpautop().33		add_filter( 'the_content', array( $this, 'run_shortcode' ), 8 );34		add_filter( 'widget_text_content', array( $this, 'run_shortcode' ), 8 );35		add_filter( 'widget_block_content', array( $this, 'run_shortcode' ), 8 );36 37		// Shortcode placeholder for strip_shortcodes().38		add_shortcode( 'embed', '__return_false' );39 40		// Attempts to embed all URLs in a post.41		add_filter( 'the_content', array( $this, 'autoembed' ), 8 );42		add_filter( 'widget_text_content', array( $this, 'autoembed' ), 8 );43		add_filter( 'widget_block_content', array( $this, 'autoembed' ), 8 );44 45		// After a post is saved, cache oEmbed items via Ajax.46		add_action( 'edit_form_advanced', array( $this, 'maybe_run_ajax_cache' ) );47		add_action( 'edit_page_form', array( $this, 'maybe_run_ajax_cache' ) );48	}49 50	/**51	 * Processes the [embed] shortcode.52	 *53	 * Since the [embed] shortcode needs to be run earlier than other shortcodes,54	 * this function removes all existing shortcodes, registers the [embed] shortcode,55	 * calls do_shortcode(), and then re-registers the old shortcodes.56	 *57	 * @global array $shortcode_tags58	 *59	 * @param string $content Content to parse.60	 * @return string Content with shortcode parsed.61	 */62	public function run_shortcode( $content ) {63		global $shortcode_tags;64 65		// Back up current registered shortcodes and clear them all out.66		$orig_shortcode_tags = $shortcode_tags;67		remove_all_shortcodes();68 69		add_shortcode( 'embed', array( $this, 'shortcode' ) );70 71		// Do the shortcode (only the [embed] one is registered).72		$content = do_shortcode( $content, true );73 74		// Put the original shortcodes back.75		$shortcode_tags = $orig_shortcode_tags;76 77		return $content;78	}79 80	/**81	 * If a post/page was saved, then output JavaScript to make82	 * an Ajax request that will call WP_Embed::cache_oembed().83	 */84	public function maybe_run_ajax_cache() {85		$post = get_post();86 87		if ( ! $post || empty( $_GET['message'] ) ) {88			return;