Retrieving events from Google Calendar

I am trying to retrieve the XML data for Google Calendar. Authentication and retrieval all works. However, when I retrieve the events, gd: data isn't included as the protocol reference documents it would be (http://code.google.com/apis/calendar/data/2.0/developers_guide_protocol.html#RetrievingWithoutQuery)

Some error messages I'm running into depending on how I'm referencing the "when" node with attribute "startTime" (my ultimate goal in this anecdote) are as follows:

Fatal error: Call to a member function attributes() on a non-object in .../googlecalendarwrapper.php on line 226 when it looks like 'startTime'=> (string) $cal->when->attributes()->startTime,

GoogleCalendarWrapper_Model::getEventsList() [googlecalendarwrapper-model.geteventslist]: Node no longer exists when it looks like 'startTime'=> strval($cal->when->attributes()->startTime),

strval() [function.strval]: Node no longer exists when it looks like 'startTime'=> strval($cal->when->attributes()), and 'startTime'=> strval($cal->when->attributes('startTime')),

Code looks like:

            $xml = new SimpleXMLElement($this->get($url, $header));

            $calendars = array();
            foreach ($xml->entry as $cal){
                    $calendars[] = array(                            
                                                         'id'=>strval($cal->id),
                                                         'published'=>strval($cal->published),
                                                         'updated'=>strval($cal->updated),
                                                         'title'=>strval($cal->title),
                                                         'content'=>strval($cal->content),
                                                         'link'=>strval($cal->link->attributes()->href),
                                                         'authorName'=>strval($cal->author->name),
                                                         'authorEmail'=>strval($cal->author->email),
                                                         'startTime'=> strval($cal->when->attributes()),
                                                        );
            }

XML:

        [0] => SimpleXMLElement Object
            (
                [id] => http://www.google.com/calendar/feeds/braden.keith%40smartersys.com/private/full/7li4mr2c81mub1hcoqktn73fbo
                [published] => 2010-06-08T17:17:43.000Z
                [updated] => 2010-06-08T17:17:43.000Z
                [category] => SimpleXMLElement Object
                    (
                        [@attributes] => Array
                            (
                                [scheme] => http://schemas.google.com/g/2005#kind
                     开发者_开发百科           [term] => http://schemas.google.com/g/2005#event
                            )

                    )

                [title] => title
                [content] => content
                [link] => Array
                    (
                        [0] => SimpleXMLElement Object
                            (
                                [@attributes] => Array
                                    (
                                        [rel] => alternate
                                        [type] => text/html
                                        [href] => https://www.google.com/calendar/hosted/smartersys.com/event?eid=N2xpNG1yMmM4MW11YjFoY29xa3RuNzNmYm8gYnJhZGVuLmtlaXRoQHNtYXJ0ZXJzeXMuY29t
                                        [title] => alternate
                                    )

                            )

                        [1] => SimpleXMLElement Object
                            (
                                [@attributes] => Array
                                    (
                                        [rel] => self
                                        [type] => application/atom+xml
                                        [href] => https://www.google.com/calendar/feeds/braden.keith%40smartersys.com/private/full/7li4mr2c81mub1hcoqktn73fbo
                                    )

                            )

                        [2] => SimpleXMLElement Object
                            (
                                [@attributes] => Array
                                    (
                                        [rel] => edit
                                        [type] => application/atom+xml
                                        [href] => https://www.google.com/calendar/feeds/braden.keith%40smartersys.com/private/full/7li4mr2c81mub1hcoqktn73fbo/63411700663
                                    )

                            )

                    )

                [author] => SimpleXMLElement Object
                    (
                        [name] => Braden Keith
                        [email] => braden.keith@smartersys.com
                    )

            )

According to this article: http://www.sitepoint.com/blogs/2005/10/20/simplexml-and-namespaces/ You have to approach namespaces a tad differently with SimpleXMLElement. The solution is as follows:

            $xml = new SimpleXMLElement($this->get($url, $header));
            $xml->asXML();

            $calendars = array();
            foreach ($xml->entry as $cal){
                    $ns_gd = $cal->children('http://schemas.google.com/g/2005');
                    $calendars[] = array(                            
                                                         'id'=>strval($cal->id),
                                                         'published'=>strval($cal->published),
                                                         'updated'=>strval($cal->updated),
                                                         'title'=>strval($cal->title),
                                                         'content'=>strval($cal->content),
                                                         'link'=>strval($cal->link->attributes()->href),
                                                         'authorName'=>strval($cal->author->name),
                                                         'authorEmail'=>strval($cal->author->email),
                                                         'startTime'=> strval($ns_gd->when->attributes()->startTime),
                                                        );
            }

Note the $ns_gd = $cal->children('http://schemas.google.com/g/2005'); - this defines the namespace. Then from there, $ns_gd->when->attributes()->startTime gets the attribute from gd:when named startTime.

Man it's been a bloody 2 days. But I figured it out. Hopefully this can help someone down the road.