Autobahn|Python: WebSocket & WAMP for Real-Time Python Applications

Introduction

Autobahn|Python is a powerful open-source library that provides robust implementations of the WebSocket Protocol and the Web Application Messaging Protocol (WAMP) for Python 3.11+. Designed to run on both Twisted and asyncio frameworks, it empowers developers to build high-performance, real-time applications. With Autobahn|Python, you can easily create clients and servers capable of bidirectional messaging, asynchronous Remote Procedure Calls (RPC), and Publish & Subscribe (PubSub) patterns, making it ideal for modern web and application communication.

Installation

Getting started with Autobahn|Python is straightforward using pip.

To install the core library:

python -m pip install autobahn

For additional functionalities, such as advanced compression, encryption, or WAMP authentication, you can install optional dependencies:

Twisted support: pip install autobahn[twisted]
Compression (Brotli recommended): pip install autobahn[compress]
Encryption & WAMP-cryptosign: pip install autobahn[encryption]
WAMP-SCRAM authentication: pip install autobahn[scram]
Native Vector Extensions (NVX) for acceleration: pip install autobahn[nvx]

Examples

Autobahn|Python simplifies the creation of real-time components. Here are two illustrative examples:

WebSocket Echo Server

This server echoes back any WebSocket message it receives:

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))

More examples and boilerplate code for running servers can be found in the official documentation.

WAMP Application Component

This example demonstrates a WAMP component performing subscribe, publish, register, and call actions:

from autobahn.twisted.wamp import ApplicationSession
# or: from autobahn.asyncio.wamp import ApplicationSession
from twisted.internet.defer import inlineCallbacks

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))

For details on running WAMP application components and routers, refer to the documentation.

Why Use Autobahn|Python?

Autobahn|Python stands out for its comprehensive feature set and commitment to performance and standards:

Dual Framework Support: Seamlessly integrates with both Twisted and asyncio, offering flexibility for Python developers.
Full Protocol Implementation: Provides complete, standards-compliant implementations of WebSocket (RFC6455) and WAMP.
High Performance: Features a fully asynchronous design, optional SIMD-accelerated native vector extensions (NVX) for WebSocket operations, and optimized serializers.
Best-in-Class Conformance: Achieves 100% strict passes with the Autobahn Testsuite, ensuring reliability and interoperability.
Advanced Features: Supports WebSocket compression (including Brotli), TLS for secure communication, and various WAMP authentication methods (WAMP-cryptosign, WAMP-SCRAM).
Robust Packaging: Offers comprehensive binary wheel coverage for CPython and PyPy across major platforms and architectures, ensuring easy installation without system dependencies.

Autobahn|Python: WebSocket & WAMP for Real-Time Python Applications

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