ydb/contrib/python/websocket-client/py2/README.md

websocket-client

websocket-client is a WebSocket client for Python. It provides access to low level APIs for WebSockets. websocket-client implements version hybi-13 of the WebSocket procotol. This client does not currently support the permessage-deflate extension from RFC 7692.

Documentation

This project's documentation can be found at https://websocket-client.readthedocs.io/

Contributing

Please see the contribution guidelines

Installation

First, install the following dependencies:

• six
• backports.ssl_match_hostname for Python 2.x

You can install the dependencies with the command pip install six and pip install backports.ssl_match_hostname

You can use either python setup.py install or pip install websocket-client to install. This module is tested on Python 2.7 and Python 3.4+. Python 3 support was first introduced in version 0.14.0, but is a work in progress.

Usage Tips

Check out the documentation's FAQ for additional guidelines: https://websocket-client.readthedocs.io/en/latest/faq.html

Known issues with this library include lack of WebSocket Compression support (RFC 7692) and minimal threading documentation/support.

License

• LGPL version 2.1

Performance

The send and validate_utf8 methods are very slow in pure Python. You can disable UTF8 validation in this library (and receive a performance enhancement) with the skip_utf8_validation parameter. If you want to get better performance, please install both numpy and wsaccel, and import them into your project files - these other libraries will automatically be used when available. Note that wsaccel can sometimes cause other issues.

Long-lived Connection

Most real-world WebSockets situations involve longer-lived connections. The WebSocketApp run_forever loop automatically tries to reconnect when a connection is lost, and provides a variety of event-based connection controls. The project documentation has additional examples

import websocket
try:
    import thread
except ImportError:
    import _thread as thread
import time

def on_message(ws, message):
    print(message)

def on_error(ws, error):
    print(error)

def on_close(ws):
    print("### closed ###")

def on_open(ws):
    def run(*args):
        for i in range(3):
            time.sleep(1)
            ws.send("Hello %d" % i)
        time.sleep(1)
        ws.close()
        print("thread terminating...")
    thread.start_new_thread(run, ())

if __name__ == "__main__":
    websocket.enableTrace(True)
    ws = websocket.WebSocketApp("ws://echo.websocket.org/",
                              on_open = on_open,
                              on_message = on_message,
                              on_error = on_error,
                              on_close = on_close)

    ws.run_forever()

Short-lived Connection

This is if you want to communicate a short message and disconnect immediately when done. For example, if you want to confirm that a WebSocket server is running and responds properly to a specific request. The project documentation has additional examples

from websocket import create_connection
ws = create_connection("ws://echo.websocket.org/")
print("Sending 'Hello, World'...")
ws.send("Hello, World")
print("Sent")
print("Receiving...")
result =  ws.recv()
print("Received '%s'" % result)
ws.close()

If you want to customize socket options, set sockopt, as seen below:

from websocket import create_connection
ws = create_connection("ws://echo.websocket.org/",
                        sockopt=((socket.IPPROTO_TCP, socket.TCP_NODELAY),))

Acknowledgements

Thanks to @battlemidget and @ralphbean for helping migrate this project to Python 3.