Update Twisted framework integration example to py3

- With maintaining support to Py2

examples/frameworks/twisted/echo_client_app.py

@@ -1,9 +1,11 @@
 # install_twisted_rector must be called before importing the reactor
+from __future__ import unicode_literals
+
 from kivy.support import install_twisted_reactor
+
 install_twisted_reactor()
 
-
-# A simple Client that send messages to the echo server
+# A Simple Client that send messages to the Echo Server
 from twisted.internet import reactor, protocol
 
 
@@ -12,20 +14,23 @@ class EchoClient(protocol.Protocol):
         self.factory.app.on_connection(self.transport)
 
     def dataReceived(self, data):
-        self.factory.app.print_message(data)
+        self.factory.app.print_message(data.decode('utf-8'))
 
 
-class EchoFactory(protocol.ClientFactory):
+class EchoClientFactory(protocol.ClientFactory):
     protocol = EchoClient
 
     def __init__(self, app):
         self.app = app
 
-    def clientConnectionLost(self, conn, reason):
-        self.app.print_message("connection lost")
+    def startedConnecting(self, connector):
+        self.app.print_message('Started to connect.')
 
-    def clientConnectionFailed(self, conn, reason):
-        self.app.print_message("connection failed")
+    def clientConnectionLost(self, connector, reason):
+        self.app.print_message('Lost connection.')
+
+    def clientConnectionFailed(self, connector, reason):
+        self.app.print_message('Connection failed.')
 
 
 from kivy.app import App
@@ -39,6 +44,8 @@ from kivy.uix.boxlayout import BoxLayout
 # the server
 class TwistedClientApp(App):
     connection = None
+    textbox = None
+    label = None
 
     def build(self):
         root = self.setup_gui()
@@ -49,26 +56,26 @@ class TwistedClientApp(App):
         self.textbox = TextInput(size_hint_y=.1, multiline=False)
         self.textbox.bind(on_text_validate=self.send_message)
         self.label = Label(text='connecting...\n')
-        self.layout = BoxLayout(orientation='vertical')
-        self.layout.add_widget(self.label)
-        self.layout.add_widget(self.textbox)
-        return self.layout
+        layout = BoxLayout(orientation='vertical')
+        layout.add_widget(self.label)
+        layout.add_widget(self.textbox)
+        return layout
 
     def connect_to_server(self):
-        reactor.connectTCP('localhost', 8000, EchoFactory(self))
+        reactor.connectTCP('localhost', 8000, EchoClientFactory(self))
 
     def on_connection(self, connection):
-        self.print_message("connected successfully!")
+        self.print_message("Connected successfully!")
         self.connection = connection
 
     def send_message(self, *args):
         msg = self.textbox.text
         if msg and self.connection:
-            self.connection.write(str(self.textbox.text))
+            self.connection.write(msg.encode('utf-8'))
             self.textbox.text = ""
 
     def print_message(self, msg):
-        self.label.text += msg + "\n"
+        self.label.text += "{}\n".format(msg)
 
 
 if __name__ == '__main__':

examples/frameworks/twisted/echo_server_app.py

@@ -1,21 +1,21 @@
 # install_twisted_rector must be called before importing and using the reactor
 from kivy.support import install_twisted_reactor
-install_twisted_reactor()
 
+install_twisted_reactor()
 
 from twisted.internet import reactor
 from twisted.internet import protocol
 
 
-class EchoProtocol(protocol.Protocol):
+class EchoServer(protocol.Protocol):
     def dataReceived(self, data):
         response = self.factory.app.handle_message(data)
         if response:
             self.transport.write(response)
 
 
-class EchoFactory(protocol.Factory):
-    protocol = EchoProtocol
+class EchoServerFactory(protocol.Factory):
+    protocol = EchoServer
 
     def __init__(self, app):
         self.app = app
@@ -26,20 +26,23 @@ from kivy.uix.label import Label
 
 
 class TwistedServerApp(App):
+    label = None
+
     def build(self):
         self.label = Label(text="server started\n")
-        reactor.listenTCP(8000, EchoFactory(self))
+        reactor.listenTCP(8000, EchoServerFactory(self))
         return self.label
 
     def handle_message(self, msg):
-        self.label.text = "received:  %s\n" % msg
+        msg = msg.decode('utf-8')
+        self.label.text = "received:  {}\n".format(msg)
 
         if msg == "ping":
-            msg = "pong"
+            msg = "Pong"
         if msg == "plop":
-            msg = "kivy rocks"
-        self.label.text += "responded: %s\n" % msg
-        return msg
+            msg = "Kivy Rocks!!!"
+        self.label.text += "responded: {}\n".format(msg)
+        return msg.encode('utf-8')
 
 
 if __name__ == '__main__':