nwebsocket 0.9.1

WebSocket client without async

Python package for simple and easy to use WebSocket clients without async.

Motivation

There are many asynchronous Python WebSocket client packages out there, and almost of them require your code to use the async syntax. This one does not, so it’s easier to use from within a Jupyter Notebook. All of the async code is executed onto a separate thread.

Installation

Install using pip

pip install nwebsocket

Python version

Python 3.7+ is required.

Usage

A simple minimal API interface can be created using the following example.

# minimal.py
from nwebsocket import WebSocket

wscn = WebSocket( "ws://localhost:8001" )

wscn.onmessage = lambda m: print( m )
wscn.onopen = lambda: print( "Opened connection" )
wscn.onclose = lambda: print( "Closed connection" )
wscn.onerror = lambda: print( "Connection errored out" )

print( wscn.readyState )

Inspiration

This package was inspired by the ultra-simple WebSocket API in the JavaScript language which it replicates.

https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/url

Guideline

Since the callback-style API is quite unusual when it comes to pythonicity, your task will be to:

• define onmessage, onopen, onclose and onerror

• handle reconnection/s

• implement the TX/RX specification for working with the endpoint

• isolate the callback pattern from the rest of your code

Take a chat service as an example, there are operations which are following the traditional request/response pattern such as posting messages, and there are other messages which are received without issuing a request (chat posting by other users).

These latter messages must be handled by your code as soon as they are received. Class instances can help with that, by storing the received information (chat posts). Keep your callbacks short, fast and serializable.

Limitations

This library is not suitable for high throughput, as the queue mechanism in Python is notoriously slow due to serialization.

License (MIT)

Copyright (C) 2022 Adapta Robotics | MATT Robot