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WebsocketParser is a RFC6455 compliant parser for websocket messages written in Ruby. It is intended to write websockets servers in Ruby, but it only handles the parsing of the WebSocket protocol, leaving I/O to the server.


Add this line to your application's Gemfile:

gem 'websocket_parser'

And then execute:

$ bundle

Or install it yourself as:

$ gem install websocket_parser


Return values

The simplest way to use the websocket parser is to create a new one, fetch it with data and query it for new messages.

require 'websocket_parser'

parser = WebSocket::Parser.new

parser.append data

parser.next_message  # return next message or nil
parser.next_messages # return an array with all parsed messages

# To send a message:

socket << WebSocket::Message.new('Hi there!').to_data

Only text or binary messages are returned on the parse methods. To intercept control frames use the parser's callbacks.

Use callbacks

In addition to return values, you can register callbacks to get notified when a certain event happens.

require 'websocket_parser'

socket = # Handle I/O with your server/event loop.

parser = WebSocket::Parser.new

parser.on_message do |m|
  puts "Received message #{m}"

parser.on_error do |m|
  puts "Received error #{m}"

parser.on_close do |status, message|
  # According to the spec the server must respond with another
  # close message before closing the connection

  socket << WebSocket::Message.close.to_data

  puts "Client closed connection. Status: #{status}. Reason: #{m}"

parser.on_ping do
  socket << WebSocket::Message.pong.to_data

parser << socket.read(4096)


Websocket Parser is still in early development phase.


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