A Simple Websocket Server written in Python

• RFC 6455 (All latest browsers)
• TLS/SSL out of the box
• Passes Autobahns Websocket Testsuite
• Support for Python 2 and 3

Original author & repository

• Dave P.
• https://github.com/dpallot/simple-websocket-server.git

Echo Server Example

from SimpleWebSocketServer import SimpleWebSocketServer, WebSocket

class SimpleEcho(WebSocket):

    def handleMessage(self):
        # echo message back to client
        self.sendMessage(self.data)

    def handleConnected(self):
        print self.address, 'connected'

    def handleClose(self):
        print self.address, 'closed'

server = SimpleWebSocketServer('', 8000, SimpleEcho)
server.serveforever()

Open websocket.html and connect to the server.

Chat Server Example

from SimpleWebSocketServer import SimpleWebSocketServer, WebSocket

clients = []
class SimpleChat(WebSocket):

    def handleMessage(self):
       for client in clients:
          if client != self:
             client.sendMessage(self.address[0] + u' - ' + self.data)

    def handleConnected(self):
       print self.address, 'connected'
       for client in clients:
          client.sendMessage(self.address[0] + u' - connected')
       clients.append(self)

    def handleClose(self):
       clients.remove(self)
       print self.address, 'closed'
       for client in clients:
          client.sendMessage(self.address[0] + u' - disconnected')

server = SimpleWebSocketServer('', 8000, SimpleChat)
server.serveforever()

Open multiple websocket.html and connect to the server.

Want to get up and running faster?

There is an example which provides a simple echo and chat server

Echo Server

python SimpleExampleServer.py --example echo

Chat Server (open up multiple websocket.html files)

python SimpleExampleServer.py --example chat

TLS/SSL Example

1. Generate a certificate with key

   openssl req -new -x509 -days 365 -nodes -out cert.pem -keyout cert.pem

2. Run the secure TSL/SSL server (in this case the cert.pem file is in the same directory)

   python SimpleExampleServer.py --example chat --ssl 1 --cert ./cert.pem

3. Offer the certificate to the browser by serving websocket.html through https. The HTTPS server will look for cert.pem in the local directory. Ensure the websocket.html is also in the same directory to where the server is run.

   sudo python SimpleHTTPSServer.py

4. Open a web browser to: https://localhost:443/websocket.html

5. Change ws://localhost:8000/ to wss://localhost:8000 and click connect.

Note: if you are having problems connecting, ensure that the certificate is added in your browser against the exception https://localhost:8000 or whatever host:port pair you want to connect to.

For the Programmers

handleConnected: called when handshake is complete

• self.address: TCP address port tuple of the endpoint

handleClose: called when the endpoint is closed or there is an error

handleMessage: gets called when there is an incoming message from the client endpoint

• self.opcode: the WebSocket frame type (STREAM, TEXT, BINARY)
• self.data: bytearray (BINARY frame) or unicode string payload (TEXT frame)
• self.request: HTTP details from the WebSocket handshake (refer to BaseHTTPRequestHandler)

sendMessage: send some text or binary data to the client endpoint

• sending data as a unicode object will send a TEXT frame
• sending data as a bytearray object will send a BINARY frame

sendClose: send close frame to endpoint

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The MIT License (MIT)