Load JSON data with URL loader - php

Question

I am new to action script 3.0. Help me to understand how can I load data with URLLoader.
So, I have an aplication like:
var PATH:String = "http://www.somesite.com/myFirstPage.php?a=10&b=20";
var urlRequest:URLRequest = new URLRequest(PATH);
var urlLoader:URLLoader = new URLLoader();
urlLoader.dataFormat = URLLoaderDataFormat.TEXT;
urlLoader.addEventListener(Event.COMPLETE, urlLoader_complete);
urlLoader.load(urlRequest);
function urlLoader_complete(evt:Event):void {
some_result = urlLoader.data;
}
php script looks like:
<?php
//retrieve GET params
int c = a + b; //a and b come from GET request
return "{{"result_equal":"20"}}"; //result in JSON
?>
I don't really understand how JSON result from .php page gets in my URLLoader object. Help me by simple example, please. Thanx!

Answer 1

You need a few things here. First off, you'll need a JSON library, because somehow it isn't built into Flash, even with their modified E4X core:
https://github.com/mikechambers/as3corelib
This should give you the following bits of code:
import com.adobe.serialization.json.JSON;
function urlLoader_complete(e:Event):void
{
var loader:URLLoader = URLLoader(e.target);
var some_result:Object = JSON.decode(loader.data);
}
Now... your PHP code is a mess. The best way to create JSON is to just use the json_encode function:
$retVal = array('result_equal'=>20);
echo json_encode($retVal);

Answer 2

You will want to use this project: https://github.com/mikechambers/as3corelib
Example usage:
<mx:Script>
<![CDATA[
import mx.collections.ArrayCollection;
import mx.rpc.events.ResultEvent;
import com.adobe.serialization.json.JSON;
private function onJSONLoad(event:ResultEvent):void
{
var rawData:String = String(event.result);
var arr:Array = (JSON.decode(rawData) as Array);
var dp:ArrayCollection = new ArrayCollection(arr);
grid.dataProvider = dp;
}
]]>
</mx:Script>
<mx:HTTPService
id="service"
resultFormat="text"
url="http://weblogs.macromedia.com/mesh/mashedpotato.json"
result="onJSONLoad(event)" />

Answer 3

PHP code should looks like this:
$result = array("result_equal" => 20);
return json_encode($result);

Answer 4

So, this is what I get: Please, say whats wrong, what good! Thanx1
package
{
import data.*;
import flash.errors.IOError;
import flash.events.Event;
import flash.events.*;
import flash.net.*;
public class UserInfoProxy
{
public static const GET_USER_INFO:DataCallConfigVO = new DataCallConfigVO( "COMMON", 'GET_USER_INFO', true, null, null);
public function UserInfoProxy()
{
trace("Start request");
var request:URLRequest = new URLRequest("http://www.avrora.com.localhost/myservlet.php");
var loader:URLLoader = new URLLoader();
loader.addEventListener(Event.COMPLETE, completeHandler);
loader.addEventListener(ProgressEvent.PROGRESS, progressHandler);
loader.addEventListener(SecurityErrorEvent.SECURITY_ERROR, securityErrorHandler);
loader.addEventListener(HTTPStatusEvent.HTTP_STATUS, httpStatusHandler);
loader.addEventListener(IOErrorEvent.IO_ERROR, ioErrorHandler);
loader.load(request);
}
private function completeHandler(event:Event):void
{
var loader:URLLoader = URLLoader(event.target);
trace("Complete");
trace("completeHandler: " + loader.data);
}
private function progressHandler(event:ProgressEvent):void
{
trace("progressHandler loaded:" + event.bytesLoaded + " total: " + event.bytesTotal);
}
private function securityErrorHandler(event:SecurityErrorEvent):void
{
trace("securityErrorHandler: " + event);
}
private function httpStatusHandler(event:HTTPStatusEvent):void
{
trace("httpStatusHandler: " + event);
}
private function ioErrorHandler(event:IOErrorEvent):void
{
trace("ioErrorHandler: " + event);
}
}
}
And this is my PHP code, that must return JSON data:
<?
//here I can process all input GET, POST params, database etc...
$someJSONresponse = "{'username':'yozhik', 'age':'18'}";
//here just echo result and it will be automatically downloaded??
echo $someJSONresponse;
?>