Problems returning complex objects from a php data service

Question

either the data services tool is buggy or i am doing something wrong. here is the code:
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
     xmlns:s="library://ns.adobe.com/flex/spark"
     xmlns:mx="library://ns.adobe.com/flex/halo"
     minWidth="1024" minHeight="768"
     xmlns:personservice="services.personservice.*"
     initialize="init()">
     <fx:Script>
          <![CDATA[
               import mx.rpc.events.ResultEvent;
               import mx.controls.Alert;
               import mx.collections.ArrayCollection;
               public var people:ArrayCollection;
               private function init():void {
                    getPeopleInMyWorldResult.token = personService.getPeopleInMyWorld();
               protected function getPeopleInMyWorldResult_resultHandler(event:ResultEvent):void {
                    people = new ArrayCollection(event.result as Array);
          ]]>
     </fx:Script>
     <fx:Declarations>
          <s:CallResponder id="getPeopleInMyWorldResult" result="getPeopleInMyWorldResult_resultHandler(event)"/>
          <personservice:PersonService id="personService"
               destination="PersonService"
               endpoint="http://localhost/photoapp/Test3-debug/gateway.php"
               fault="Alert.show(event.fault.faultString)"
               showBusyCursor="true"
               source="PersonService"/>
     </fx:Declarations>
</s:Application>
<?php
class Person {
     public $name;
     public $cars;
class Car {
     public $year;
     public $make;
     public $model;
class PersonService {
     public function getPeopleInMyWorld() {
          $person1 = new Person();
          $person1->name = "John Doe";
          $car1 = new Car();
          $car1->year = 2005;
          $car1->make = 'audi';
          $car1->model = 'A6 Quattro';
          $car2 = new Car();
          $car2->year = 1970;
          $car2->make = 'datsun';
          $car2->model = '510';
          $person1->cars = array($car1, $car2);
          $person2 = new Person();
          $person2->name = "Jane Doe";
          return array($person1, $person2);
create a new "flex" project in FB Beta1 with a php server. Setup the application and php script as normal, then configure the return type for the getPeopleInMyWorld function. I created a new return type called "Person" and was quite please to see that FB automagically created a "Cars" class with the all the right properties.
Unfortunately, if you run the code (try debug mode and put a breakpoint on the result handler) you'll notice that "john doe" has lost his cars and that you also get the silent (check console) error:
TypeError: Error #1034: Type Coercion failed: cannot convert []@1226bc49 to mx.collections.ArrayCollection.
any ideas??
i can get this to work by using json, but it's extra work, the com.adobe.serializers.json.JSONDecoder has little documentation, and the method outlined above is just begging to work.
so, how are the rest of you getting complex data back from your servers? json?? amfphp?? xml (but surely not)??
also, since i'm here discussing data services, if any adobe ppl are about, please throw one extra voice behind the following feature requests:
1) support for optional service call arguments (http://bugs.adobe.com/jira/browse/FB-19659)
2) a button for automatically 'generating service calls' from within the data services panel.
thanks,
- e

Answer 1

Thank you Gaurav for pointing me in the right direction. There was some debate in the blogs as to which data transferring method (amfphp, json, or xml) was best. See
http://blogs.adobe.com/mikepotter/2006/07/php_and_flex_js.html
and
http://www.5etdemi.com/blog/archives/2006/12/clearing-the-fud-on-amfphps-speed-versus-json -and-xml/
I used json yesterday
php:  json_encode(array($p1, $p2));   // observation: you only have to encode once as opposed
                                      // to using amf on each array...
FB:   private var jsonD:JSONDecoder = new JSONDecoder();
      var jsonString:String = {{{return result from service call}}}
      myPeople:ArrayCollection = jsonD.decode(jsonString, services.personservice.Person);
Note that in FB you can use the services.personservice.Person class as an optional argument in the jsonD.decode function. This class can be automatically generated using FB's built-in data service's panel when you try to configure the return type (as I described above). The json data should unserialize correctly with Cars objects automagically created and everything (a huge time saver!!).
It worked for me, though I'm not sure how deep the unserialization process is capable of going (objects within objects w/in objects, for example). Also I had some trouble with adobe's jsonDecoder; it had trouble eating (uhm parsing) hollow objects (i.e. objects with null properties), whereas the php_encode / php_decode handled these objects w/o fail.
Anyway, will be reading up on amf. Tanx again Gaurav,
- e