Async::WebSocket

A simple asynchronous websocket client/server implementation for HTTP/1 and HTTP/2.

Installation

Add this line to your application's Gemfile:

gem 'async-websocket'

And then execute:

$ bundle

Or install it yourself as:

$ gem install async-websocket

Usage

There are examples which include:

• A command line chat client/server which can read input from stdin and send messages to the server.
• A small MUD client/server which uses JSON for communation between client/server.
• A utopia-based web application which uses a JavaScript client to connect to a web application server.

Client Side with Async

#!/usr/bin/env ruby

require 'async'
require 'async/io/stream'
require 'async/http/endpoint'
require 'async/websocket/client'

USER = ARGV.pop || "anonymous"
URL = ARGV.pop || "http://localhost:7070"

Async do |task|
	stdin = Async::IO::Stream.new(
		Async::IO::Generic.new($stdin)
	)
	
	endpoint = Async::HTTP::Endpoint.parse(URL)
	
	Async::WebSocket::Client.connect(endpoint) do |connection|
		input_task = task.async do
			while line = stdin.read_until("\n")
				connection.write({user: USER, text: line})
				connection.flush
			end
		end
		
		connection.write({
			user: USER,
			status: "connected",
		})
		
		while message = connection.read
			puts message.inspect
		end
	ensure
		input_task&.stop
	end
end

Server Side with Rack & Falcon

#!/usr/bin/env -S falcon serve --bind http://localhost:7070 --count 1 -c

require 'async/websocket/adapters/rack'
require 'set'

$connections = Set.new

run lambda {|env|
	Async::WebSocket::Adapters::Rack.open(env, protocols: ['ws']) do |connection|
		$connections << connection
		
		while message = connection.read
			$connections.each do |connection|
				connection.write(message)
				connection.flush
			end
		end
	ensure
		$connections.delete(connection)
	end or [200, {}, ["Hello World"]]
}

Force HTTP/1 Connection

This forces the endpoint to connect using HTTP/1.1.

endpoint = Async::HTTP::Endpoint.parse("https://remote-server.com", alpn_protocols: Async::HTTP::Protocol::HTTP11.names)

Async::WebSocket::Client.connect(endpoint) do ...

You may want to use this if the server advertises HTTP/2 but doesn't support HTTP/2 for WebSocket connections.

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

License

Released under the MIT license.

Copyright, 2015, by Samuel G. D. Williams.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.