How to pass data from Google App Engine(Python) to Flex 4 application

Answer 1

The best way to talk from Flex to GAE is using AMF. Here is how:

app.yaml

application: flexandthecloud
version: 3
runtime: python
api_version: 1

handlers:
- url: /services/.*
  script: main.py

main.py

#!/usr/bin/env python
import wsgiref.handlers

from pyamf.remoting.gateway.wsgi import WSGIGateway

def sayHello(name):
  return "howdy " + name

services = {
    'services.sayHello': sayHello
}

def main():
  application = WSGIGateway(services)
  wsgiref.handlers.CGIHandler().run(application)

if __name__ == '__main__':
  main()

Flex 3 code (can be easily modified for Flex 4):

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"&gt;

    <mx:RemoteObject id="ro" destination="services" endpoint="http://flexandthecloud.appspot.com/services/"&gt;
        <mx:result>
            l.text = event.result as String;
        </mx:result>
    </mx:RemoteObject>

    <mx:TextInput id="ti"/>
    <mx:Label id="l"/>
    <mx:Button label="say hello" click="ro.sayHello(ti.text)"/>

</mx:Application>

Answer 2

What's in your index.html? You can pass the values to index.html, set a javascript function like:

function passvalue {
    PassParameter("userVO", "{{userVO}}");
}

Then set a function in Flex:

public function gethtmlparam(name:String, val:String):void {
            switch (name) {
                case "userVO": userVO= val; break;}
}

and call back these two function in :

ExternalInterface.addCallback("PassParameter", gethtmlparam);

Hope it can help.

Answer 3

Based on your comment to James Ward's response, I wonder if you can accomplish what you need with a FlashVars param element?

http://livedocs.adobe.com/flex/3/html/help.html?content=passingarguments_3.html

You will probably just need to adjust the index.html template to build the FlashVars param element.

Edit: 6 Mar

You might try looking at: http://polygeek.com/801_flex_reading-flashvars-in-flex

You need to be sure you wait until the app has been loaded to access the flashVars.

Edit: 7 Mar

Correct, in those examples they hard code the value. You need to edit your template so the value is set to the value of the template parameter.

So, in index.html: flashvars.userVO = "{{ userVO }}"