This library implements the WebSocket protocol, striving for safety, correctness, and ergonomics. It is based on the wsproto project, which is a Sans-IO state machine that implements the majority of the WebSocket protocol, including framing, codecs, and events. This library handles I/O using the Trio framework. This library passes the Autobahn Test Suite.
This README contains a brief introduction to the project. Full documentation is available here.
This library requires Python 3.5 or greater. To install from PyPI:
pip install trio-websocket
This example demonstrates how to open a WebSocket URL:
import trio from sys import stderr from trio_websocket import open_websocket_url async def main(): try: async with open_websocket_url('wss://echo.websocket.org') as ws: await ws.send_message('hello world!') message = await ws.get_message() print('Received message: %s' % message) except OSError as ose: print('Connection attempt failed: %s' % ose, file=stderr) trio.run(main)
The WebSocket context manager connects automatically before entering the block and disconnects automatically before exiting the block. The full API offers a lot of flexibility and additional options.
A WebSocket server requires a bind address, a port, and a coroutine to handle incoming connections. This example demonstrates an "echo server" that replies to each incoming message with an identical outgoing message.
import trio from trio_websocket import serve_websocket, ConnectionClosed async def echo_server(request): ws = await request.accept() while True: try: message = await ws.get_message() await ws.send_message(message) except ConnectionClosed: break async def main(): await serve_websocket(echo_server, '127.0.0.1', 8000, ssl_context=None) trio.run(main)
The server's handler
echo_server(…) receives a connection request object.
This object can be used to inspect the client's request and modify the
handshake, then it can be exchanged for an actual WebSocket object
Again, the full API offers a lot of flexibility and additional options.