Kyle’s Pile

Honestly, when I first attempted to parse and access Google Calendar XML from flash I had a lot of trouble with it. I spent a lot of hours being frustrated by XML namespaces (it was the first time I’d had to use them) and consequently had to move to the forums at actionscript.org. I was helped by a guy with the alias “wvxvw” (which is a nice palendrome, lol) so I’d like to extend credit to him for giving me a nudge in the right direction. Anyway, lets get on to the code.

First things first you need a URLLoader object to load Google Calendar’s xml. This looks like:

var xmlReq:URLRequest = new URLRequest(xmlURL);
var xmlLoader:URLLoader = new URLLoader(xmlReq);

xmlLoader.addEventListener(IOErrorEvent.IO_ERROR, onIOError);
xmlLoader.addEventListener(SecurityErrorEvent.SECURITY_ERROR, onSecurityError);
xmlLoader.addEventListener(Event.COMPLETE, xmlGCALLoaded);

To pass the XML’s URL to the URLLoader you need to use the URLRequest class, but its really simple because the constructor takes your URL as an argument so its only one line of code. In fact, if you want it even shorter you could do this:

var xmlLoader:URLLoader = new URLLoader(new URLRequest(xmlURL));

Either way is fine, obviously. Its important to note here that I am using the “full” version of the code that Google Calendar passes to you. If you use the basic you will find it much more difficult to work with the event startTime and endTime. After that be sure to add the proper Event Listeners. The IOError will be thrown if the URL doesn’t return any data (and perhaps for some other reasons too that I don’t know about). The Security Error is thrown when you violate your sandbox (which is a complicated idea, you should look it up if you’d like more info). And of course, the Event.COMPLETE is what is triggered when the data is finished loading, which takes us to the next block of code:

private function xmlGCALLoaded(evt:Event):void {
var xmlData:XML = XML(evt.target.data);
   var ns:Namespace = xmlData.namespace();
}

In this function we take the supplied data (our XML) which is noted as “evt.target.data” and put it into the xmlData variable. Using the method supplied by the XML class we can access the first namespace available to us and place it into the “ns” variable. A namespace in XML is denoted by a tag attribute “xmlns” for instance in google’s opening tag:

This will be useful when we try to access different parts of the XML google has given us. From this first namespace we call any of the properties about the calendar it’s self such as the author or id:

var author:String = xmlData.ns::author;

However, I imagine the primary reason you want this XML data is to access the “entry”, better known as the calendar events. To do this you’ll want to make another namespace (there is a deeper namespace level for accessing events and event properties). In AS3 we find out how many “entry” tags there are, loop through them, and pull the info that we want from it and place them into array or objects or whatever we’d like:

var numEntries:int = xmlData.ns::entry.length();
var xmlObj:Object;

for (var j:int=0; j<numEntries; j++) {
   var gdns:Namespace = xmlData.ns::entry[j].namespace("gd");
   xmlObj = new Object();
   xmlObj.eventTitle = xmlData.ns::entry[j].children().(name().localName == "title");
   xmlObj.startDate = createXMLDate( xmlData.ns::entry[j].gdns::when.@startTime );
   xmlObj.endDate = createXMLDate( xmlData.ns::entry[j].gdns::when.@endTime );
   xmlObj.eventWhere = xmlData.ns::entry[j].gdns::where.@valueString;
   entries.push(xmlObj);
}

We get the number of entries from the first namespace’s entry.length() which is a function provided by the XML Class. Then we loop those entries and for each one find the new namespace (also, this namespace was provided for us in the first tag, I just chose to do it this way instead). With this new namespace we are able to access the inner node of the given entry. The use of the “@” symbol lets us access the attributes of the tags, which is where the data we are seeking is. Anyway, once you have looped all the entries they are available to you in an easy to use array format.

If you’d like to see the full working AS3 Class for the Google XML Parser, you can download it from this link: googleCalendarXML Class

The rar’d version (includes the .fla for compilation) can be found from this link:gCalXML Project

To see a full project that implements this Google Calendar XML Parser, click here.

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