Flex prevent URL encoding of params with HTTPRequest - apache-flex

Question

I'm trying to port an existing AJAX app to Flex, and having trouble with the encoding of parameters sent to the backend service.
When trying to perform the action of deleting a contact, the existing app performs a POST, sending the the following: (captured with firebug)
contactRequest.contacts[0].contactId=2c33ddc6012a100096326b40a501ec72
So, I create the following code:
var service:HTTPService;
function initalizeService():void
{
service = new HTTPService();
service.url = "http://someservice";
service.method = 'POST';
}
public function sendReq():void
{
var params:Object = new Object();
params['contactRequest.contacts[0].contactId'] = '2c33ddc6012a100097876b40a501ec72';
service.send(params);
}
In firebug, I see this sent out as follows:
Content-type: application/x-www-form-urlencoded
Content-length: 77
contactRequest%2Econtacts%5B0%5D%2EcontactId=2c33ddc6012a100097876b40a501ec72
Flex is URL encoding the params before sending them, and we're getting an error returned from the server.
How do I disable this encoding, and get the params sent as-is, without the URL encoding?
I feel like the contentType property should be the key - but neither of the defined values work.
Also, I've considered writing a SerializationFilter, but this seems like overkill - is there a simpler way?

Answer 1

Writing a SerializtionFilter seemed to do the trick:
public class MyFilter extends SerializationFilter
{
public function MyFilter()
{
super();
}
override public function serializeBody(operation:AbstractOperation, obj:Object):Object
{
var s:String = "";
var classinfo:Object = ObjectUtil.getClassInfo(obj);
for each (var p:* in classinfo.properties)
{
var val:* = obj[p];
if (val != null)
{
if (s.length > 0)
s += "&";
s += StringUtil.substitute("{0}={1}",p,val);
}
}
return s;
}
}
I'd love to know any alternative solutions that don't involve doing this though!