Get the thumbnail of a given video from Youtube or Vimeo

_skin.class.php

	// ... add this to your _skin.class.php ...

	/**
	 *	The following methods have been added in order to get the thumbnail of a given video
	 *
	 *	In order to make this work, you should do the following:
	 *
	 *  1. Add these functions to the _skin.class.php file of your skin
	 *  2. Create a text custom field called "video_thumb"
	 *  3. Add a section of code in the posts.main.php file, just above the ITEM BLOCK section 
	 *     Warning: this method may vary depending on what version of b2evolution are you currently running
	 *		
	 *		$excerpt_before_text = '<div class="excerpt">';
	 *
	 *		if( $Item->video_thumb = $Item->get_custom_field_value( 'video_thumb' ) )
	 *	        {
	 *	            if($thumb_url = $Skin->decode_tag($Item->video_thumb))
	 *	            {
	 *	                $excerpt_before_text .= '<img src="'.$thumb_url.'" style="float: left;">';
	 *	            }
	 *	        }
	 *
	 *		// ---------------------- ITEM BLOCK INCLUDED HERE ------------------------
	 *		skin_include( '_item_block.inc.php', array(
	 *				'content_mode' => 'auto',		// 'auto' will auto select depending on $disp-detail
	 *				'image_size'	 =>	'fit-400x320',
	 *				'excerpt_before_text' => $excerpt_before_text,
	 *			) );
	 *
	 */

	static public function youtube_apicall( $video_id ) 
	{
		$data = new stdClass;
		$data->thumb_url = "http://img.youtube.com/vi/" . $video_id . "/0.jpg";

		return $data;
	}

	static public function vimeo_apicall( $video_id )
	{
		$hash = unserialize(file_get_contents('http://vimeo.com/api/v2/video/'.$video_id.".php"));
		$data = new stdClass;
		$data->thumb_url = $hash[0]['thumbnail_medium'];

		return $data;
	}

	function decode_tag( $tag )
	{
		$providers = array('youtube', 'vimeo');

		preg_match('#\[video:('.implode('|', $providers).'):(.+?)]#', $tag, $matches);

		if( $data = call_user_func('self::'.$matches[1].'_apicall', $matches[2]) )
		{
			return $data->thumb_url;
		}
		else
		{
			return false;
		}
	}