WS-RS

Lightweight, event-driven WebSockets for Rust.

/// A WebSocket echo server
listen("127.0.0.1:3012", |out| {
    move |msg| {
        out.send(msg)
    }
})

Introduction

This library provides an implementation of WebSockets, RFC6455 using MIO. It allows for handling multiple connections on a single thread, and even spawning new client connections on the same thread. This makes for very fast and resource efficient WebSockets. The API design abstracts away the menial parts of the WebSocket protocol, masking and unmasking frames, which allows you to focus on application code and rely on WS-RS to handle protocol conformance. However, it is also possible to get low-level access to individual WebSocket frames if you need to write extensions or want to optimize around the WebSocket protocol.

API documentation

Examples

• Server. A simple WebSocket echo server using closures.
• Client A simple WebSocket client for connecting to an echo server using closures.
• Single Threaded An example of an echo client and an echo server on one thread using closures.
• Threads An example of an echo client and an echo server on separate threads. This demonstrates using a struct as a WebSocket handler.
• Channels A more complex example using channels to communicate with a WebSocket handler to accomplish a separate task.
• Pong An example demonstrating how to send and recieve a custom ping/pong frame.

Stability and Testing

WS-RS passes both the client and server sides of the Autobahn Testsuite. To run the tests yourself, install the Autobahn Testsuite. For example:

mkvirtualenv wstest --python=/usr/bin/python2
pip install autobahntestsuite

To run the client tests, start the test server in one window:

cd tests
wstest -m fuzzingserver

And run the WS-RS client in the other:

cargo run --example autobahn-client

To run the server tests, start the WS-RS server in one window:

cargo run --example autobahn-server

And run the test client in the other:

cd tests
wstest -m fuzzingclient

SSL

WS-RS supports WebSocket connections using SSL (e.g. wss://mysecure/websocket). To enable the ssl feature, require WS-RS in your Cargo.toml file as so:

[dependencies.ws]
version = "*"
features = ["ssl"]

Then simply specify the wss scheme to use an encypted connection.

/// An encypted Websocket echo client
connect("wss://localhost:3012", |ws| {
    move |msg| {
        ws.send(msg)
    }
})

Note: The ssl feature is currently not available on Windows.

Contributing

Please report bugs and make feature requests here. I welcome pull requests. Unit tests for bugs are greatly appreciated.

Comparison with other WebSocket libraries

You don't need to use this library to the exclusion of other WebSocket libraries, in Rust or other languages, but if you find yourself considering which library to use, here is my opinion: choose the one that has the API you like the most. The API is generally more important than performance. The library API is what you will have to deal with as you build your WebSocket application. I've written WS-RS to have an API that fits my needs. If you don't like it, please make a feature request to improve it or use another library that causes you less problems.

However, if performance is what you value most and you want a WebSocket library in Rust, I would choose this one. Here is how it stacks up against some other common frameworks using the example benchmark tool to open 10,000 simultaneous connections and send 10 messages. These results are not reliable as a serious benchmark:

Library	Time (ms)
WS-RS	1,709
libwebsockets	2,067
rust-websocket	8,950
* websockets CPython 3.4.3	12,638
Autobahn CPython 2.7.10	48,902
** NodeJS via ws	127,635

* websockets encountered a few (3) broken pipe errors
** NodeJS encountered several (229) connection timeout errors

Your results will vary. The system specs for this test were as follows:

Intel(R) Core(TM) i3 CPU 560 @ 3.33GHz, 8GB RAM