flairpy

In last few weeks I start to integrate Python with Flash Platform using XML and now with XML Socket.

There are some methods to make a connection from a Python to Flash or Fle; you can use XML or PyAMF, that is a way to communicate between an application and a remote server with a compact binary representation that can be transferred over HTTP/HTTPS.
You can also work with XML Socket to create a fast and 2 ways communication between Python and Flash or Flex.
In this case we’ll use XML Socket to create a chat application where Python will be our server-side language and Flex and AIR will be our desktop application.
If you work for the first time with AIR you must know few things that help you to understand better the AIR world.

AIR (Adobe Integrated Runtime) is a new Adobe technology that allow developers and designers to bring online contents and, with the same programming language, work on desktop environment.

If you want to install an AIR application you MUST have AIR runtime installed in your computer, you can download it directly from Adobe site and it’s totally free and CROSS-PLATFORM!
In fact when you deploy an AIR application you can deliver it on MAC OS, WIN or Linux and you don’t change anything! This is amazing!

AIR integrates 4 web technologies together like HTML, Javascript, SWF and PDF and they could work together if you need it.
To work with Flex and AIR you only install in Eclipse or Aptana the Flex Builder plug-in that you can find on Adobe site, or if you don’t use those IDE, you can download Flex Builder standalone version that integrates both technologies.

So now we start to talk about our first experiments with Python, AIR and Flex.
First of all, you can create a Python file with this code:

# import socket and select module

import socket, select

# define checkData function that is the core of our Socket comunication

def checkData():

#create an infinitive loop to check data from an AIR client to another one

    while True:

# use select module to allow an application to wait for input from multiple sockets at a time

inputready,outputready,exceptready = select.select(input,[],[])

        for s in inputready: 

            if s == theSock: 

            # add a client to the socket connection

                client, address = theSock.accept() 

                input.append(client) 

            else:

            # comunication between client and server: manage traffic data

                data = s.recv(1024)

# in tempConn we put all client without server connection 

                tempConn = input[1:len(input)]

                if data:

                    for i in tempConn:

# send to all client any messages

                        i.send(str(i.getsockname()[0]) + “: ” + data)

                else:client.close()

#define socket connection: address, port and type of socket connection

theAddress = (’localhost’,1024)

theSock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

theSock.bind(theAddress)

theSock.listen(5)

input = [theSock]

#after established XMLSocket connection, manage messages from client

checkData()

OK, Python side we have done!

Now we start with Flex/AIR part, so I comment all steps, if you have any suggestions or doubt feel free to add a comment and will be a pleasure to reply:

After create a new Flex project in Eclipse or Flex Builder, based on Adobe AIR you can find 2 files in src folder: an .mxml file and a .xml file.
The first one is a Flex file (mxml is Flex format file) where you can define your GUI and, with Actionscript 3, logic of your AIR application; the second one is an XML configuration file of your desktop application where you can sets a lots of parameters like size of your application, name of window, type of window and so on.
I suggest to take a look at Adobe Devnet site where you can find lots of tutorial about Flex, Flash, AJAX and AIR.

In our Flex project copy and paste this code:

<?xml version=”1.0″ encoding=”utf-8″?>

<mx:WindowedApplication xmlns:mx=”http://www.adobe.com/2006/mxml” layout=”absolute” creationComplete=”init()”>

<mx:Script>

<![CDATA[

private var srv:XMLSocket;

private function init():void{

srv = new XMLSocket()

srv.addEventListener(DataEvent.DATA, traceData)

srv.addEventListener(IOErrorEvent.IO_ERROR, setErr)

srv.addEventListener(Event.CONNECT, getConn)

srv.addEventListener(Event.CLOSE, closeHandler);

srv.connect("localhost", 1024)

}

private function closeHandler(e:Event):void{

chatMessage.text += "//****LOGOUT FLAIRPY CHAT****\\";

}

private function getConn(e:Event):void{

chatMessage.text += "//****LOGIN FLAIRPY CHAT****\\";

}

private function setErr(e:IOErrorEvent):void{

chatMessage.text += e.text;

}

private function traceData(e:DataEvent):void{

chatMessage.text += e.data + "\n"

}

private function sendMessage():void{

srv.send(lblT.text);

}

]]>

</mx:Script>

<mx:VBox width=”50%” height=”50%“>

<mx:HBox>

<mx:TextInput id=”lblT” width=”100“/>

<mx:Button label=”send” click=”sendMessage()”/>

</mx:HBox>

<mx:TextArea id=”chatMessage” editable=”false” width=”100%” height=”50%” />

</mx:VBox>

</mx:WindowedApplication>

In the Script tag you can find all Actionscript language that allow you to connect your AIR application to Socket and how to manage all events that Socket triggers when you work with AIR application.
In fact we are listen events (srv.addEventListener(…)) when Socket connection start, close and when we receive data from other Socket connection, in Actionscript you work mainly with asynchronous methods, only with some AIR API (we take a look at that in next blog posts) you can work synchronous methods.
In MXML language we have define all GUI of our desktop application, in particular we use some containers to organize our GUI (HBox, VBox, and so on) and in those components we put a textarea, to show chat history, a textinput that allow user to send a message to the server, and a button that call a function (sendMessage()) where send messages to our XML Socket.

Finally to test this sample, remember to launch first Python script and then AIR application, if you don’t make this sequence AIR application thrown an error when you try to send a message to the server.

TIPS&TRICKS: if you try to send a string from Python to Flex/AIR application, remember to close your sentence with “\0″ because client side must understand when string terminate.

I upload also sources code to download Python and Flex/AIR samples.
For any questions please leave a comment at this post