Cairngorm 3 Module Library

At work recently I have been looking at the Cairngorm 3 Module Library. It does some pretty cool things for example:

• Skinnable ModuleLoader that displays loading and error states for a module
• Lazy loads modules when parsley events are dispatched
• Passes events to modules when they have loaded

The last item is what I was trying to get to work. We wanted to dispatch a loadSomeData event. The services that would load that data however are not initially available and need to be loaded in a module. Using a lazy load policy this module would be loaded and the event would then be passed to the module so that the loadSomeData Command would fire. Our CommandResult handler in the main application would then fire when the data had loaded.

To set this you need to set a few things up. You need a ParsleyModuleDescriptor in your application context:

<cairngorm:parsleymoduledescriptor
    url="SampleModule.swf"
    objectid="sampleModule"
    />

A lazy load policy in your context:

<cairngorm:LazyModuleLoadPolicy
    objectId="lazyLoadPolicy"
    type="{ ModuleInitialisationEvent }"
    />

And a ModuleViewLoader in your application:

<module:ModuleViewLoader
    moduleManager="{ moduleManager }"
    skinClass="{ ModuleViewLoaderSkin }"
    loadPolicy="{ lazyLoadPolicy }"
    />

This is enough to load the module when the ModuleInitialisationEvent is dispatched but the event will not be passed to the module as when the event is dispatched the module context is not yet initialised.

To solve this problem we need a ModuleMessageInterceptor tag, again in our application context:

<cairngorm:ModuleMessageInterceptor
    type="{ ModuleInitialisationEvent }"
    moduleRef="sampleModule"
    />

Now this should all work but as you can see from the sample app here it doesn’t. The module loads but the event does not get passed to the module (a working version of the sample app is here).

To fix this I had to patch the Cairngorm Module Library. There are actually 2 separate problems that I have reported in the 2 bugs listed here and here.

If you want to get your lazy loading modules to work correctly without patching Cairngorm then you need to make sure that your messageHandler or Command in the module is locally scoped. This does however mean that global CommandResult handlers won’t work for any results from the call.

You also need to make sure that your ModuleViewLoader has a moduleID and that your initialisation event has the same moduleId in and has the ModuleId Meta Data Tag.

I hope that my 2 patches for these fixes will be incorporated into trunk soon so that they will be available without patches.

Google IO Announcements

Over the past few days there have been a lot of announcements from Google at their IO event. There has been a lot of good news for the flash community and good news for android phone owners. As I am a Flex developer and have an android phone this has been exciting times!

The most exciting announcement for me was the fact that the AIR pre-release for android is now open:

http://blogs.adobe.com/air/2010/05/air_android_prerelease.html

A while ago I tried a bit of android development and started to think about writing a cycle computer application for my android phone. Now that we get AIR on Android though I can write this application much quicker in Flex. I can still get the geo-location and accelerometer data which is all I need.
The other advantage of course is that the application will work on any other device that supports AIR.

I am also very excited by all the cool new features coming in the next version of Android. I just hope it’s not too long before it’s released.

Setting up Apache and IIS on the same machine

Just a quick note to myself more than anything so I remember in the future.

I am currently trying to get both IIS and Apache running on my web server. The reason for this is because I want to move my SVN server from my home server to my remote server. This will mean that my SVN server can have it’s own static IP and run with apache on port 80 as a http server.

The problem was that by default IIS binds to all the IP addresses available to the server so that Apache was not able to bind to any.

I found this blog post very helpful.

To summarise:

• Make sure httpcfg is installed – you might need to download the support tools
• type the following command for each IP address that you want IIS to listen on:
  httpcfg set iplisten –i XXX.XXX.XXX.XXX
• confirm the IP list you have created with:
  httpcfg query iplisten
• restart http service:
  net stop http /y
  net start w3svc

That’s it. I now have Apache and IIS running on my server, both on port 80 but on different IPs. Now all I have to do is link Apache up to SVN and copy my dump of my local repository across.

SWCInspector v 0.2

I’ve uploaded a new version of SWCInspector. People at work, including myself, are already finding this pretty useful even with this early set of features.

The new version is here. I’ll update this html page to point at new versions as I upload them.

New features / fixes:

• Big improvements to the renderers – they were very dodgy on scrolling before
• Added a label to the selected asset indicating class name and swc that it came from
• Added the ability to draw a box to display the asset bounds
• Display bounds in the property pane so you can check 0,0 registration
• Improved the width and height adjustment
• Improvements to model wiring – more parsley based

If you find this useful let me know. I’ve got a lot more features that I want to implement but if you have any suggestions let me know.

The wife is away this weekend so hopefully there’ll be another version before Monday!

SwcInspector

At work all the assets that we use to create the applications are contained in swcs. These swcs are created in Flash and are used like any other library in Flex.

There can be a lot of assets and it can be hard to find the one that you are looking for. It is also handy to be able to test the asset before it actually gets into the application – see what states are defined and how it looks when it is re-sized to make sure the slice-9 is set up properly.

As we’re just getting to a point on my current project where we’re getting lots of assets delivered I put SwcInspector together this weekend. It is not finished yet but there is already quite a bit of useful functionality in there:

• The ability to load multiple swcs into the application
• Filtering of loaded asset list
• Visibility of states defined for each asset
• Resizing of assets to test slice-9
• Adjustment of background color for white / light assets

As I said it’s not finished. The existing functionality needs some tweaking and there is some more functionality that I want to implement.

Unfortunately I can’t let you have a copy of the assets we use at work for obvious reasons. I found this swc courtesy of this blog for you to download and try out with the application if you so want to.

You can have a look at the application here. Using it with a swc with only 1 asset isn’t really a very good example but that’s all I’ve got I’m afraid! If you use swcs yourself give it a try and let me know how it goes – I have only been able to test it on a few so  wouldn’t be surprised if there are issues.

I’ll post again when I’ve made some progress. I can make the code available to anyone who’d like a look. If you want a copy please e-mail me.

AsyncTokenWrapper is Dead, Long Live AsyncTokenWrapper

As I said in the comments of my last post about AsyncTokenWrapper I didn’t like the way I was wrapping AsyncToken and handling the response.

A much neater solution to this is to create and register a custom command factory. You register a command based on the return type of your function. In my case I am returning a ProcessingAsyncToken so I go about registering my factory like this:

GlobalFactoryRegistry.instance.messageRouter.addCommandFactory( 
	ProcessingAsyncToken, 
	new ProcessingCommandFactory()
);

I do this in a support class that implements ContextBuilderProcessor so that I can set this up when I create my context:

My command factory looks like this:

public class ProcessingCommandFactory implements CommandFactory
{
	public function createCommand( 
		returnValue : Object, 
		message : Object, 
		selector : * = null 
	) : Command
	{
		return new ProcessingCommand( returnValue, 
			message, 
			selector 
		);
	}
}

And just returns a new instance of my ProcessingCommand:

public class ProcessingCommand extends AbstractCommand
{

	//-------------------------------------------------
	//
	//	Constructor
	//
	//-------------------------------------------------

	public function ProcessingCommand( 
		returnValue : *, 
		message : Object, 
		selector : * 
	)
	{
		super( returnValue, message, selector );

		_processingToken = ProcessingAsyncToken( returnValue );

		_processingToken.token.addResponder( 
			new Responder( complete, error )
		);
		
		start();
	}

	//-------------------------------------------------
	//
	//	Private Variables
	//
	//-------------------------------------------------
	
	private var _processingToken : ProcessingAsyncToken;
	
	//-------------------------------------------------
	//
	//	Overridden Methods: AbstractCommand
	//
	//-------------------------------------------------

	protected override function selectResultValue( 
		result : *, 
		targetType : ClassInfo 
	) : *
	{
		return ( targetType.getClass() != ResultEvent && result is ResultEvent )
			? ResultEvent( result ).result
			: result;
	}

	protected override function selectErrorValue( 
		result : *, 
		targetType : ClassInfo 
	) : *
	{
		return ( targetType.getClass() == Fault && result is FaultEvent )
			? FaultEvent( result ).fault
			: result;
	}

	override protected function complete( result : * = null ) : void
	{
		var argumentsArray : Array;
		
		if ( _processingToken.resultProcessingFunction != null )
		{
			try{
				argumentsArray = _processingToken.resultProcessingArguments.concat();
				argumentsArray.unshift( result.result );
				result = _processingToken.resultProcessingFunction.apply( 
					this, 
					argumentsArray );
			}
			catch( e : Error )
			{
				error( e );
			}
		}

		super.complete( result );
	}

	override protected function error( result : * = null ) : void
	{
		var argumentsArray : Array;
		
		if ( _processingToken.faultProcessingFunction != null )
		{
			argumentsArray = _processingToken.faultProcessingArguments.concat();
			argumentsArray.unshift( result.fault );
			result = _processingToken.faultProcessingFunction.apply( 
				this, 
				argumentsArray );
		}
		super.error( result );
	}

}

We just extend AbstractCommand and override the complete and error functions to apply the functions defined in ProcessingAsyncToken before passing the result on. In the constructor we add a responder to the AsyncToken in the return Value.

I call the function as follows:

[Command( type="com.pricklythistle.picasa.event.ListPicasaAlbumsEvent", messageProperties="userID,kind" )]
public function loadUserAlbums( 
	userID : String, 
	kind : String = null 
) : ProcessingAsyncToken
{
	url = StringUtil.substitute( BASE_URL, userID );
	
	return loadUserEntries( kind );
}

I think this is a much neater solution that wrapping an AsyncToken inside another Async token – that had a really bad smell about it!

Android Development – emulator problems

I just had my first go at android development. SO far I have managed to get Hello World running on my phone in debug mode but unfortunately I can’t get the emulator running which is going to make development harder.

I’ve posted a question on stack overflow so hopefully some helpful person will be able to help me out.