WebSocket & WAMP for Python on Twisted and asyncio.

Autobahn|Python is a subproject of Autobahn and provides open-source implementations of

• The WebSocket Protocol
• The Web Application Messaging Protocol (WAMP)

for Python 2 and 3, and running on Twisted and asyncio.

You can use Autobahn|Python to create clients and servers in Python speaking just plain WebSocket or WAMP.

WebSocket allows bidirectional real-time messaging on the Web and beyond, while WAMP adds real-time application communication on top of WebSocket.

WAMP provides asynchronous Remote Procedure Calls and Publish & Subscribe for applications in one protocol running over WebSocket. WAMP is a routed protocol, so you need a WAMP Router to connect your Autobahn|Python based clients. We provide Crossbar.io, but there are other options as well.

• framework for WebSocket and WAMP clients and servers
• compatible with Python 2.7 and 3.3 or later
• runs on CPython, PyPy and Jython
• runs under Twisted and asyncio - implements WebSocket RFC6455 and Draft Hybi-10+
• implements WebSocket compression
• implements WAMP, the Web Application Messaging Protocol
• high-performance, fully asynchronous implementation
• best-in-class standards conformance (100% strict passes with Autobahn Testsuite: Client Server)
• message-, frame- and streaming-APIs for WebSocket
• supports TLS (secure WebSocket) and proxies
• Open-source (MIT license)

To give you a first impression, here are two examples. We have lot more in the repo.

Here is a simple WebSocket Echo Server that will echo back any WebSocket message received:

from autobahn.twisted.websocket import WebSocketServerProtocol # or: from autobahn.asyncio.websocket import WebSocketServerProtocol class MyServerProtocol(WebSocketServerProtocol): def onConnect(self, request): print("Client connecting: {}".format(request.peer)) def onOpen(self): print("WebSocket connection open.") def onMessage(self, payload, isBinary): if isBinary: print("Binary message received: {} bytes".format(len(payload))) else: print("Text message received: {}".format(payload.decode('utf8'))) # echo back message verbatim self.sendMessage(payload, isBinary) def onClose(self, wasClean, code, reason): print("WebSocket connection closed: {}".format(reason))

To actually run above server protocol, you need some lines of boilerplate.

Here is a WAMP Application Component that performs all four types of actions that WAMP provides:

1. subscribe to a topic
2. publish an event
3. register a procedure
4. call a procedure

from autobahn.twisted.wamp import ApplicationSession # or: from autobahn.asyncio.wamp import ApplicationSession class MyComponent(ApplicationSession): @inlineCallbacks def onJoin(self, details): # 1. subscribe to a topic so we receive events def onevent(msg): print("Got event: {}".format(msg)) yield self.subscribe(onevent, 'com.myapp.hello') # 2. publish an event to a topic self.publish('com.myapp.hello', 'Hello, world!') # 3. register a procedure for remote calling def add2(x, y): return x + y self.register(add2, 'com.myapp.add2'); # 4. call a remote procedure res = yield self.call('com.myapp.add2', 2, 3) print("Got result: {}".format(res))

Above code will work on Twisted and asyncio by changing a single line (the base class of MyComponent). To actually run above application component, you need some lines of boilerplate and a WAMP Router.