[WordPress] faux-Embed support for xkcd comics

xkcd-ombed.php

<?php
/*
Plugin Name: xkcd oEmbed
Description: faux-Embed support for xkcd comics
*/

$xkcd_oembed = new xkcd_oEmbed();

class xkcd_oEmbed {

	function __construct() {
		wp_embed_register_handler( 'xkcd', '#http:\/\/(?:www.|)xkcd\.com\/(\d+)\/?#i', array( &$this, 'get_xkcd' ) );
	}

	function get_xkcd( $matches, $attr, $url, $rawattr ) {
		$id = $matches[1];

		$xkcd_cache = 'xkcd_cache_'. $id;
		// delete_transient( $xkcd_cache );
		if ( false === ( $img = get_transient( $xkcd_cache ) ) ) {

			$get = wp_remote_get( $url );
			$response = wp_remote_retrieve_response_code( $get );
			if ( 404 == $response ) {
				$img = make_clickable( "$url (comic not found)" );
				set_transient( $xkcd_cache, $img, 60 * 60 ); // cache for an hour, try again later
				return $img;
			}

			$body = wp_remote_retrieve_body( $get );

			// cut off crud before the comic
			$_body = explode( '<div id="comic">', $body );
			$body = array_pop( $_body );
			// cut off crud after the comic
			$_body = explode( '</div>', $body );
			$img = array_shift( $_body );

			$img .= "<a href='$url'>xkcd #{$id}</a>";

			set_transient( $xkcd_cache, $img, 60 * 60 * 24 * 30 * 12 ); // cache for a while. expiry value of 0 is auto-loaded, which we don't need/want
		}
		return "<p>{$img}</p>";
	}

}