add reconnecting WebSocket client

examples/twisted/websocket/reconnecting/README.md

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+# Auto Reconnecting WebSocket Client
+
+This example demonstrates a WebSocket client that automatically retries connecting when the server connection is lost (or could not be established in the first place).
+
+The reconnection schedule is doing proper exponential backoff. Please see Twisted documentation for [ReconnectingClientFactory](http://twistedmatrix.com/documents/current/api/twisted.internet.protocol.ReconnectingClientFactory.html)
+
+## Running
+
+Start the server in a first terminal:
+
+	python server.py
+
+Now start the client in a second terminal:
+
+	python client.py
+
+Then stop the server. The client looses the connection. Restart the server. The client will automatically reconnect to the server.
+
+You can also start the client before starting the server. The client will connect when the server comes up (upon next reconnection schedule).
+

examples/twisted/websocket/reconnecting/client.py

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+###############################################################################
+##
+##  Copyright (C) 2011-2014 Tavendo GmbH
+##
+##  Licensed under the Apache License, Version 2.0 (the "License");
+##  you may not use this file except in compliance with the License.
+##  You may obtain a copy of the License at
+##
+##      http://www.apache.org/licenses/LICENSE-2.0
+##
+##  Unless required by applicable law or agreed to in writing, software
+##  distributed under the License is distributed on an "AS IS" BASIS,
+##  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+##  See the License for the specific language governing permissions and
+##  limitations under the License.
+##
+###############################################################################
+
+from twisted.internet.protocol import ReconnectingClientFactory
+
+from autobahn.twisted.websocket import WebSocketClientProtocol, \
+                                       WebSocketClientFactory
+
+
+
+class MyClientProtocol(WebSocketClientProtocol):
+
+   def onConnect(self, response):
+      print("Server connected: {0}".format(response.peer))
+
+   def onOpen(self):
+      print("WebSocket connection open.")
+
+      def hello():
+         self.sendMessage(u"Hello, world!".encode('utf8'))
+         self.sendMessage(b"\x00\x01\x03\x04", isBinary = True)
+         self.factory.reactor.callLater(1, hello)
+
+      ## start sending messages every second ..
+      hello()
+
+   def onMessage(self, payload, isBinary):
+      if isBinary:
+         print("Binary message received: {0} bytes".format(len(payload)))
+      else:
+         print("Text message received: {0}".format(payload.decode('utf8')))
+
+   def onClose(self, wasClean, code, reason):
+      print("WebSocket connection closed: {0}".format(reason))
+
+
+
+class MyClientFactory(WebSocketClientFactory, ReconnectingClientFactory):
+
+   protocol = MyClientProtocol
+
+   def clientConnectionFailed(self, connector, reason):
+      print("Client connection failed .. retrying ..")
+      self.retry(connector)
+
+   def clientConnectionLost(self, connector, reason):
+      print("Client connection lost .. retrying ..")
+      self.retry(connector)
+
+
+
+if __name__ == '__main__':
+
+   import sys
+
+   from twisted.python import log
+   from twisted.internet import reactor
+
+   log.startLogging(sys.stdout)
+
+   factory = MyClientFactory("ws://localhost:9000", debug = False)
+
+   reactor.connectTCP("127.0.0.1", 9000, factory)
+   reactor.run()

examples/twisted/websocket/reconnecting/server.py

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+###############################################################################
+##
+##  Copyright (C) 2011-2014 Tavendo GmbH
+##
+##  Licensed under the Apache License, Version 2.0 (the "License");
+##  you may not use this file except in compliance with the License.
+##  You may obtain a copy of the License at
+##
+##      http://www.apache.org/licenses/LICENSE-2.0
+##
+##  Unless required by applicable law or agreed to in writing, software
+##  distributed under the License is distributed on an "AS IS" BASIS,
+##  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+##  See the License for the specific language governing permissions and
+##  limitations under the License.
+##
+###############################################################################
+
+from autobahn.twisted.websocket import WebSocketServerProtocol, \
+                                       WebSocketServerFactory
+
+
+class MyServerProtocol(WebSocketServerProtocol):
+
+   def onConnect(self, request):
+      print("Client connecting: {0}".format(request.peer))
+
+   def onOpen(self):
+      print("WebSocket connection open.")
+
+   def onMessage(self, payload, isBinary):
+      if isBinary:
+         print("Binary message received: {0} bytes".format(len(payload)))
+      else:
+         print("Text message received: {0}".format(payload.decode('utf8')))
+
+      ## echo back message verbatim
+      self.sendMessage(payload, isBinary)
+
+   def onClose(self, wasClean, code, reason):
+      print("WebSocket connection closed: {0}".format(reason))
+
+
+
+if __name__ == '__main__':
+
+   import sys
+
+   from twisted.python import log
+   from twisted.internet import reactor
+
+   log.startLogging(sys.stdout)
+
+   factory = WebSocketServerFactory("ws://localhost:9000", debug = False)
+   factory.protocol = MyServerProtocol
+
+   reactor.listenTCP(9000, factory)
+   reactor.run()