Google Docs Embed

<?php
/*
Plugin Name: Google Docs Embed
Plugin URI: http://en.bainternet.info
Description: Simple plugin that provides a shortcode to embed PDF ,Word document or PowerPoint presentation.
Version: 1.0
Author: Bainternet
Author URI: http://en.bainternet.info
*/
/*
        *   Copyright (C) 2011  Ohad Raz
        *   http://en.bainternet.info
        *   admin@bainternet.info

        This program is free software; you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation; either version 2 of the License, or
        (at your option) any later version.

        This program is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        GNU General Public License for more details.

        You should have received a copy of the GNU General Public License
        along with this program; if not, write to the Free Software
        Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

/* Disallow direct access to the plugin file */
if (basename($_SERVER['PHP_SELF']) == basename (__FILE__)) {
    //die('Sorry, but you cannot access this page directly.');
}

add_shortcode('GDOCS', 'Gdocs_embed');
function Gdocs_embed( $atts, $content = null ) {
    extract( shortcode_atts( array(
        'height' => 300,
        'width' => 400,
        'style' => '',
        'title' => '',
        'class' => 'pdf',
        'id' => '',
        'url' => ''
        ), $atts ) );



    if (!strstr($url,'http://')) {
        return '';
    }

        $embed = '<iframe src="http://docs.google.com/viewer?url='.urlencode($url).'&amp;embedded=true" style="height:'.$height.'px;width:'.$width.'px;" class="'.$class.'"';
    if ($id != '') {
        $embed .= ' id="'.$id.'"';
    }
    if ($style != '') {
        $embed .= ' style="'.$style.'"';
    }
    if ($title != '') {
        $embed .= ' title="'.$title.'"';
    }
    $embed .= '></iframe>';

    return apply_filters( 'GDOCS', $embed  );
}

/*
Usage:

[GDOCS url="http://link.to/PDF"]
*/