GCalendar

This add-on contains some additional methodes for google calendar feeds and the corresponding events. Please consider that it is in an early stage so don't blame me for some bugs and I'm sure the simplepie cracks will add some corrections and improvements too. For any questions and remarks please feel free to post in the add-on forum. The whole thing is in action in the gcalendar joomla extension.

1. Download the latest version from the download repository. Or grab the most actual source from svn.
2. Extract the zip file somewher in your local filesystem.
3. Copy the file src/simplepie-gcalendar.php to a folder where your simplepie library is.
4. On the SimplePie-enabled page you want to use this extension on, make sure you include it in the same way that you include simplepie.inc

<?php
 
/**
* Google calendar simplepie feed.
* 
* @author allon
* @version $Revision: 0.1.0 $
**/
 
if (!defined('SIMPLEPIE_NAMESPACE_GOOGLE_CALENDAR_ITEM')) {
	define('SIMPLEPIE_NAMESPACE_GOOGLE_CALENDAR_ITEM', 'http://schemas.google.com/g/2005');
}
 
if (!defined('SIMPLEPIE_NAMESPACE_GOOGLE_CALENDAR_FEED')) {
	define('SIMPLEPIE_NAMESPACE_GOOGLE_CALENDAR_FEED', 'http://schemas.google.com/gCal/2005');
}
 
/**
 * SimplePie_GCalendar is the SimplePie extension which provides some
 * helper methods as well as a correct sorting of the items.
 */
class SimplePie_GCalendar extends SimplePie {
 
	var $show_past_events = FALSE;
	var $sort_ascending = TRUE;
	var $orderby_by_start_date = TRUE;
	var $expand_single_events = TRUE;
 
	/**
	 * If the method $this->get_items() should include past events.
	 */
	function set_show_past_events($value = FALSE){
		$this->show_past_events = $value;
	}
 
	/**
	 * If is set to true the closest event is the first in the returning items.
	 * So it makes sense to call enable_order_by_date(false) before fetching
	 * the data to prevent from sorting twice.
	 */
	function set_sort_ascending($value = TRUE){
		$this->sort_ascending = $value;
	}
 
	/**
	 * The method $this->get_items() will return the events ordered by
	 * the start date if set to true otherwise by the publish date.
	 * 
	 */
	function set_orderby_by_start_date($value = TRUE){
		$this->orderby_by_start_date = $value;
	}
 
	/**
	 * If the method $this->get_items() should treat reccuring events
	 * as one item.
	 */
	function set_expand_single_events($value = TRUE){
		$this->expand_single_events = $value;
	}
 
	/**
	 * Overrides the default ini method and sets automatically 
	 * SimplePie_Item_GCalendar as item class.
	 * It ensures that the feed url is correct if $calendar_type=='full'.
	 */
	function init(){
		$this->set_item_class('SimplePie_Item_GCalendar');
 
		$new_url;
		if (!empty($this->multifeed_url)){
			$tmp = array();
			foreach ($this->multifeed_url as $value)
				$tmp[] = $this->check_url($value);
			$new_url = $tmp;
		}else
			$new_url = $this->check_url($this->feed_url);
		$this->set_feed_url($new_url);
 
		parent::init();
	}
 
	/**
	 * Creates an url depending on the variables $show_past_events, etc.
	 * and returns a valid google calendar feed url.
	 */
	function check_url($url_to_check){
		$tmp = str_replace("/basic","/full",$url_to_check);
		if(!strpos($tmp,'?'))
			$tmp = $this->append($tmp,'?');
		else{
			if(!(substr($tmp, -1) === '&'))
				$tmp = $this->append($tmp,'&');
		}
		if($this->show_past_events)
			$tmp = $this->append($tmp,'futureevents=false&');
		else
			$tmp = $this->append($tmp,'futureevents=true&');
		if($this->sort_ascending)
			$tmp = $this->append($tmp,'sortorder=ascending&');
		else
			$tmp = $this->append($tmp,'sortorder=descending&');
		if($this->orderby_by_start_date)
			$tmp = $this->append($tmp,'orderby=starttime&');
		else
			$tmp = $this->append($tmp,'orderby=lastmodified&');
		if($this->expand_single_events)
			$tmp = $this->append($tmp,'singleevents=true&');
		else
			$tmp = $this->append($tmp,'singleevents=false&');
		return $tmp;
	}
 
	/**
	 * Internal helper method to append a straing to an other one.
	 */
	function append($value, $appendix){
		$pos = strpos($value,$appendix);
		if($pos === FALSE)
			$value .= $appendix;
		return $value;
	}
 
	/**
	 * Returns the timezone of the feed.
	 */
	function get_timezone(){
		$tzvalue = $this->get_feed_tags(SIMPLEPIE_NAMESPACE_GOOGLE_CALENDAR_FEED, 'timezone');
		return $tzvalue[0]['attribs']['']['value'];
	}
 
	/**
	 * Creates a valid feed url for the given email address.
	 */
	function create_feed_url($email_address){
		return 'http://www.google.com/calendar/feeds/'.$email_address.'/public/full';
	}
}
 
/**
 * The GCalendar Item which provides more google calendar specific
 * functions like the location of the event, etc.
 */
class SimplePie_Item_GCalendar extends SimplePie_Item {
 
	function get_id(){
		return substr($this->get_link(),strpos(strtolower($this->get_link()),'eid=')+4);
	}
 
	function get_publish_date(){
		$pubdate = $this->get_date('Y-m-d\TH:i:s\Z');
		return SimplePie_Item_GCalendar::tstamptotime($pubdate);
	}
 
	function get_location(){
		$gd_where = $this->get_item_tags(SIMPLEPIE_NAMESPACE_GOOGLE_CALENDAR_ITEM, 'where');
		return $gd_where[0]['attribs']['']['valueString'];
	}
 
	function get_status(){
		$gd_where = $this->get_item_tags(SIMPLEPIE_NAMESPACE_GOOGLE_CALENDAR_ITEM, 'eventStatus');
		return substr( $gd_status[0]['attribs']['']['value'], -8);
	}
 
	function get_start_time($as_timestamp = TRUE){ 
		$when = $this->get_item_tags(SIMPLEPIE_NAMESPACE_GOOGLE_CALENDAR_ITEM, 'when');
		$startdate = $when[0]['attribs']['']['startTime'];
		if($as_timestamp)
			return SimplePie_Item_GCalendar::tstamptotime($startdate);
		return $startdate;
	}
 
	function get_end_time($as_timestamp = TRUE){
		$when = $this->get_item_tags(SIMPLEPIE_NAMESPACE_GOOGLE_CALENDAR_ITEM, 'when');
		$enddate = $when[0]['attribs']['']['endTime'];
		if($as_timestamp)
			return SimplePie_Item_GCalendar::tstamptotime($enddate);
		return $enddate;
	}
 
	function tstamptotime($tstamp) {
        // converts ISODATE to unix date
        // 1984-09-01T14:21:31Z
		sscanf($tstamp,"%u-%u-%uT%u:%u:%uZ",$year,$month,$day,$hour,$min,$sec);
		$newtstamp=mktime($hour,$min,$sec,$month,$day,$year);
		return $newtstamp;
    }
}

1. Download the latest version from the download repository.
2. Extract the zip file somewher in your local filesystem.
3. Copy the demo folder to your web server.
4. Open with a web browser the index.php file in the demo folder.

<?php
$url = $_POST["feedurl"];
$email = $_POST["email"];
$show_past_events = $_POST["past"];
$sort_ascending = $_POST["asc"];
$order_by = $_POST["order"];
$expand_single_events = $_POST["expand"];
?>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Simplepie -- GGalendar
</head>
<body>
<h1>Simplepie Google Calendar demo web site</h1>
	<form name="input" action="index.php" method="post">
<table>
<tr>
<td>Feed url:</td>
<td><input type="text" name="feedurl" size="100" value="<?php echo $url; ?>"></td>
</tr>
<tr>
<td>OR</td>
<td></td>
</tr>
<tr>
<td>EMail address:</td>
<td><input type="text" name="email" size="100" value="<?php echo $email; ?>"></td>
</tr>
<tr>
<td>Show past events:</td>
<td><input type="radio" name="past" value="1">True<br>
<input type="radio" name="past" value="0" checked>False</td>
</tr>
<tr>
<td>Sort ascending:</td>
<td><input type="radio" name="asc" value="1" checked>True<br>
<input type="radio" name="asc" value="0">False</td>
</tr>
<tr>
<td>Order by start date:</td>
<td><input type="radio" name="order" value="1" checked>True<br>
<input type="radio" name="order" value="0">False</td>
</tr>
<tr>
<td>Expand single events:</td>
<td><input type="radio" name="expand" value="1" checked>True<br>
<input type="radio" name="expand" value="0">False</td>
</tr>
<tr><td><input type="submit" value="Submit"></td></tr>
</table>
</form>
<?php
 
require_once ('simplepie.inc');
require_once ('simplepie-gcalendar.php');
 
if(!empty($email))
	$url = SimplePie_GCalendar::create_feed_url($email);
if(empty($url))return;
$content = FALSE;
 
$feed = new SimplePie_GCalendar();
$feed->set_show_past_events($show_past_events==1);
$feed->set_sort_ascending($sort_ascending==1);
$feed->set_orderby_by_start_date($order_by==1);
$feed->set_expand_single_events($expand_single_events==1);
 
$feed->set_feed_url($url);
 
if(!$content){
	$feed->enable_order_by_date(FALSE);
	$feed->init();
 
	$feed->handle_content_type();
	$gcalendar_data = $feed->get_items();
	echo '<p>feed url: '.$feed->feed_url.'</p>';
 
	for ($i = 0; $i < sizeof($gcalendar_data) ; $i++){
		$item = $gcalendar_data[$i];
		$startDate = date("d.m.Y H:i", $item->get_start_time());
		$pubDate = date("d.m.Y H:i", $item->get_publish_date());
		echo '<p>'.$startDate.'<br>Published: '.$pubDate.'<br>'.$item->get_title().'<br>'.$item->get_description().'<hr></p>';
	}
}else{
	//header("content-Type: text/text");
	$content = '<font>';
	$content .= file_get_contents($url);
	$content .= '</font>';
	echo $content;
}
?>
</body></html>