Passing on optional arguments in ActionScript 3

11 Aug, 2008 Adobe Flex, Tips & Tricks AS3 Flex

The other day I ran into a small problem with optional arguments in Flex. While writing my tutorial on AMFPHP and Flex I decided to create a small static class that would take care of all the boring stuff with calling AMFPHP. This class enables me to simply use AMFPHP.send(”ServiceName”, and so on).

However, writing the class I realized I wouldn’t be able to pass on the optional parameters. If I would use:

function send(anArgument:Object, …args)

…I wouldn’t be able to send the args argument to the NetConnection.call method, because actionscript would send a “bunched up” array with all the arguments as ONE parameter to the call method, as opposed to a series of parameters, which was what I wanted.

The solution to this is using the Function.apply() method. What I did was to create an empty array and add a series of arguments I wanted to pass on to a function, create a reference to the function and then use the apply method. This is what my finished static method looks like:

public static function send(serviceFunction:String, resultHandler:Function, faultHandler:Function, … args:*) : void

{
trace("AMFPHP("+serviceFunction+")");
// Create responder
var responder:Responder = new Responder(resultHandler, faultHandler);
// Create an array that will temporarily store all the arguments
var collectArgs:Array = new Array;
// Add the fixed arguments
collectArgs.push(serviceFunction);
collectArgs.push(responder);
// Loop through the optional arguments and add them too
for (var i:uint=0; i<args.length; i++)
{
collectArgs.push(args[i]);
}
// Create a reference to the function we will call
var callFunction:Function = connection.call;
// Call the function using the arguments
callFunction.apply(connection,collectArgs);
}

11 Comments so far »

Brendan said,

Wrote on September 28, 2008 @ 11:58 am

Was trying to do the exact same thing got stuck found this … BEAUTIFUL!!! Thanks a million
Dale said,

Wrote on January 16, 2009 @ 5:44 am

Awesome, thanks for the example!
sandrar said,

Wrote on September 10, 2009 @ 4:46 pm

Hi! I was surfing and found your blog post… nice! I love your blog. Cheers! Sandra. R.
Pim said,

Wrote on October 14, 2009 @ 12:13 pm

Excellent! I really couldn’t think of this by myself
Thanks for your help!
amfphp said,

Wrote on October 27, 2009 @ 5:20 am

Are you using amfphp?? Is it good? Why do you want to use amfphp??
Daniel Eneström said,

Wrote on October 27, 2009 @ 10:46 am

I’ve been using AMFPHP since its “youth”, because at the beginning it was the only option I had for sending objects and arrays to and from PHP and maintaining the data format. Today there are other options, but it still works so smoothly for me, and using a wrapper that takes care of the AS-stuff I have no need to look for an alternative. Why? Do you prefer another remoting library?
InnoleDangore said,

Wrote on December 12, 2009 @ 1:58 am

Amazing, really awesome issue. I will blog about it also.
Sangpil Research» Blog Archive » using …args as function to send data to amfPHP. said,

Wrote on March 12, 2010 @ 3:40 am

[...] Links. Daniel Eneström’s blog ActionScript 3.0 References : flash_10, [...]
Aby said,

Wrote on March 27, 2010 @ 4:39 am

Thanks dude. Just what I was looking for.
Siddhant said,

Wrote on May 7, 2010 @ 2:16 pm

Never thought would get the exact solution i needed .. i was trying to right a similar class and was stuck after using args directly … thanks a lot ….
Mark said,

Wrote on July 8, 2010 @ 11:45 pm

Awesome post – Huge thanks ! I was doing exactly the same thing (amfphp & drupal) and this had me stumped for an hour or so until I found this. Only been writing AS3 for a couple of days as I am a C++/C#/Java guy normally.

May blog my resulting AS3 Drupal connector and publish code – so will add this blog to the code comments if thats ok.

Thanks,
Mark