em-websocket-server

• em-websocket-server allows the creation of efficient, evented, websocket services

Installation

gem install em-websocket-server -s http://gemcutter.org

Dependencies

• eventmachine http://github.com/eventmachine/eventmachine

Explain

To leverage em-websocket-server, you simply need to extend EM::WebSocket::Server and register the server with eventmachine. When a client connects, EventMachine will create a new instance of your class, and allow your application specific code to be executed in the context of said instance.

Methods to override:

#called on exception
on_error error

#called when a client sends a message
on_receive msg

#called when a client connects
on_connect

#called when a client is disconnected
on_disconnect

Other useful methods

#send a message
send_message msg

#close the connection
unbind

Macros

macros are used to configure your application server.

class MySweetHandler < EM::WebSocket::Server

  #secure incoming connections
  secure

  #secure incoming connections, with given key/cert
  secure {
    :private_key_file => "/path/to/private/key",
    :cert_chain_file => "/path/to/ssl/certificate"
  }

  #provide a flash socket policy
  flash_policy "/usr/local/policies/domain.com/crossdomain.xml"    

end

Quick Example

require "rubygems"
require "em-websocket-server"

class EchoServer < EM::WebSocket::Server

  def on_connect
    EM::WebSocket::Log.debug "Connected"
  end

  def on_receive msg
    send_message msg
  end

end

EM.run do
    EM.start_server "0.0.0.0", 8000, EchoServer
end

SSL

class SecureEchoServer < EM::WebSocket::Server

  #provide cert and key
  secure {
    :private_key_file => "/path/to/private/key",
    :cert_chain_file => "/path/to/ssl/certificate"
  }

  ...

end

EM.run do
    EM.start_server "0.0.0.0", 443, SecureEchoServer
end

Custom Flash Policy

class FlashyEchoServer < EM::WebSocket::Server
  flash_policy "/usr/local/policies/domain.com/crossdomain.xml"
end

EM.run do
    EM.start_server "0.0.0.0", 8000, FlashyEchoServer
end

Todo

• Testing
• Better inline documentation
• Web client library with flash based fallback

Thanks

• sidonath
• TheBreeze