websockets

.. image:: logo/horizontal.svg :width: 480px :alt: websockets

|licence| |version| |pyversions| |tests| |docs| |openssf|

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.. |version| image:: https://img.shields.io/pypi/v/websockets.svg :target: https://pypi.python.org/pypi/websockets

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What is websockets?

websockets is a library for building WebSocket_ servers and clients in Python with a focus on correctness, simplicity, robustness, and performance.

.. _WebSocket: https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API

Built on top of asyncio, Python's standard asynchronous I/O framework, the default implementation provides an elegant coroutine-based API.

An implementation on top of threading and a Sans-I/O implementation are also available.

Documentation is available on Read the Docs. <https://websockets.readthedocs.io/>_

.. copy-pasted because GitHub doesn't support the include directive

Here's an echo server with the asyncio API:

.. code:: python

#!/usr/bin/env python

import asyncio
from websockets.asyncio.server import serve

async def echo(websocket):
    async for message in websocket:
        await websocket.send(message)

async def main():
    async with serve(echo, "localhost", 8765) as server:
        await server.serve_forever()

asyncio.run(main())

Here's how a client sends and receives messages with the threading API:

.. code:: python

#!/usr/bin/env python

from websockets.sync.client import connect

def hello():
    with connect("ws://localhost:8765") as websocket:
        websocket.send("Hello world!")
        message = websocket.recv()
        print(f"Received: {message}")

hello()

Does that look good?

Get started with the tutorial! <https://websockets.readthedocs.io/en/stable/intro/index.html>_

Why should I use websockets?

The development of websockets is shaped by four principles:

1. Correctness: websockets is heavily tested for compliance with :rfc:6455. Continuous integration fails under 100% branch coverage.

2. Simplicity: all you need to understand is msg = await ws.recv() and await ws.send(msg). websockets takes care of managing connections so you can focus on your application.

3. Robustness: websockets is built for production. For example, it was the only library to handle backpressure correctly_ before the issue became widely known in the Python community.

4. Performance: memory usage is optimized and configurable. A C extension accelerates expensive operations. It's pre-compiled for Linux, macOS and Windows and packaged in the wheel format for each system and Python version.

Documentation is a first class concern in the project. Head over to Read the Docs_ and see for yourself.

.. _Read the Docs: https://websockets.readthedocs.io/ .. _handle backpressure correctly: https://vorpus.org/blog/some-thoughts-on-asynchronous-api-design-in-a-post-asyncawait-world/#websocket-servers

Why shouldn't I use websockets?

• If you prefer callbacks over coroutines: websockets was created to provide the best coroutine-based API to manage WebSocket connections in Python. Pick another library for a callback-based API.

• If you're looking for a mixed HTTP / WebSocket library: websockets aims at being an excellent implementation of :rfc:6455: The WebSocket Protocol and :rfc:7692: Compression Extensions for WebSocket. Its support for HTTP is minimal — just enough for an HTTP health check.

  If you want to do both in the same server, look at HTTP + WebSocket servers that build on top of websockets to support WebSocket connections, like uvicorn_ or Sanic_.

.. _uvicorn: https://www.uvicorn.org/ .. _Sanic: https://sanic.dev/en/

What else?

Bug reports, patches and suggestions are welcome!

To report a security vulnerability, please use the Tidelift security contact_. Tidelift will coordinate the fix and disclosure.

.. _Tidelift security contact: https://tidelift.com/security

For anything else, please open an issue_ or send a pull request_.

.. _issue: https://github.com/python-websockets/websockets/issues/new .. _pull request: https://github.com/python-websockets/websockets/compare/

Participants must uphold the Contributor Covenant code of conduct_.

.. _Contributor Covenant code of conduct: https://github.com/python-websockets/websockets/blob/main/CODE_OF_CONDUCT.md

websockets is released under the BSD license_.

.. _BSD license: https://github.com/python-websockets/websockets/blob/main/LICENSE