Multipart/form-data using HTTPService, sending a binary file and some text in the same request.

Question

Hi There,
         I am new to FLEX and also new to writing a client for a web service.
My question is more about flex (Flash builder 4.5) APIs, what APIs to use.
I want to access a web service, that's published here.
https://build.phonegap.com/docs/write_api
here is the description of webservice
===========
1) I have to do a post on POST https://build.phonegap.com/api/v1/apps
2) content type has to be "multipart/form-data"
3) JSON bodies of requests are expected to have the name 'data'
  data will be someting like this
'data={"title":"API V1 App","package":"com.alunny.apiv1","version":"0.1.0","create_method":"file"}'
4) include a zip file in the multipart body of your post, with the parameter name 'file'.
===========
I want to make a 'multipart/form-data' Post and send
one string and one zip file.
My first question to self was If i send both string + binary data in the body ...
how will server understand where string end and where zip file starts?
Then read on W3.org( http://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.2 )
How is text + binary data can be sent through "multipart/form-data" post requst.
there has to be some boundries.
After this I read and example in flex and  tried following it.
http://codeio.wordpress.com/2010/04/03/5-minutes-on-adobe-flex-mimic-file-upload-for-in-me mory-contents/
but it doesn't seems to be working for me.
                    public function createNewApp(cb:Function , appFile : File):void
                              var service:HTTPService = new HTTPService();
                              service.url = ROOT+"apps";
                              service.showBusyCursor = true;
                              service.addEventListener(ResultEvent.RESULT, function(e:ResultEvent):void {
                                        //translate JSON
                                        trace(e.result);
                                        var result:String = e.result.toString();
                                        var data:Object = JSON.parse(result);
                                        cb(data.link);
                              service.addEventListener(FaultEvent.FAULT, defaultFaultHandler); //todo : allow user to add his own as well
                              authAndUploadNewApp(service,appFile);
                    private function authAndUploadNewApp(service:HTTPService,appFile : File):void {
                              var encoder:Base64Encoder = new Base64Encoder();
                              encoder.encode(username + ":"+password);
                              service.headers = {Accept:"application/json", Authorization:"Basic " + encoder.toString()};
                              service.method ="POST";
                              var boundary:String = UIDUtil.createUID();
                              service.contentType = "multipart/form-data; boundary=—————————" + boundary;
                              var stream:FileStream = new FileStream();
                              stream.open(appFile, FileMode.READ);
                              var binaryData:ByteArray = new ByteArray();
                              var fileData : String = new String();
                              stream.readBytes(binaryData);
                              stream.close();
                              fileData = binaryData.readUTFBytes(binaryData.bytesAvailable); // I think this is where I have problem.... how do
                       //how do i converrt this bytearray/stream of data to string and send it in my post request's body - i guess if this step work rest should work..  
                              var params: String = new String();
                              var content:String = "—————————" + boundary + "nr";
                              content += 'Content-Disposition: form-data; name="data";' + '{"title":"ELS test app 2","package":"com.elsapp.captivate","version":"12.3.09","create_method":"file"}' + "nr";
                              content += "—————————" + boundary + "nr";
                              content += 'Content-Disposition: form-data; name="file";' + fileData  + "nr";
                              content += "—————————–" + boundary + "–nr";
                              service.request = content;
                              service.send();

Answer 1

In the past I have used URLVariables with URLRequest and URLLoader to achieve this kind of requirement.
Check out http://livedocs.adobe.com/flex/3/html/help.html?content=17_Networking_and_communications_3 .html which should be useful. My preference has always been to use this style instead of HTTPService objects, giving you a little more control which is what you need here.
Let me know if you need any more assistance.