a websocket example

oshi.rb

require 'rubygems'
require 'eventmachine'
require 'em-websocket'
require 'json'

class Connection
  attr_accessor :socket, :user_id
  
  def initialize(socket, user_id)
    @socket = socket
    @user_id = user_id
  end
end

class Oshi
  
  attr_accessor :connections
  
  def initialize()
    @connections = {}  
  end
  
  def connect(socket, user_id)
    @connections[user_id] = Connection.new(socket, user_id)
    puts "Number of Connections: #{@connections.size}"
  end
  
  def disconnect(socket, user_id)
    @connections.delete(user_id)
  end
  
  def broadcast(message)
    @connections.each do |user_id, connection|
      connection.socket.send(message)
    end
  end
  
  def send_message_to_user(user_id, message)
    @connections[user_id].socket.send(message)
  end

end

class RailsHandler < EventMachine::Connection
  attr_accessor :oshi
  
  def post_init
    puts "RailsHandler connection connection opened"
  end
  
  def receive_data(data)
    puts "Recieved RailsHandler message : #{data}"
    data = JSON data
    controller, action = data["pair"].split("#")
    oshi.send action, *data["args"]
  end
  
  def unbind
    puts "RailsHandler connection connection closed"
  end

end

EventMachine.run {

  @oshi = Oshi.new
  
  host, rails_handler_port, web_socket_port = "192.localhost", 8090, 8080
  
  EventMachine::start_server host, rails_handler_port, RailsHandler do |c|
    c.oshi = @oshi
  end
  
  EventMachine::WebSocket.start(:host => host, :port => web_socket_port) do |socket|
  
    socket.onopen {
      user_id = socket.request["Query"]["user_id"]
      @oshi.connect(socket, user_id)
      puts "WebSocket connection opened for #{user_id}"
    }
  
    socket.onmessage { |message|
      puts "Recieved WebSocket message: #{message}"
      
      params = JSON message
      
      reply = @oshi.send(params["action"], socket,  params["data"]["user_id"])
      
      #@oshi.send_message_to_user(params["data"]["user_id"], reply ) if reply
    }

    socket.onclose {
      user_id = socket.request["Query"]["user_id"] if socket.request["Query"]
      @oshi.disconnect(socket, user_id)
      puts "WebSocket connection closed for #{user_id}"
    }
  end
}


class HomeController < ApplicationController
  
  def test
    oshi_push "Chat#broadcast", "#{current_user.name} has connected"
  end
  
  protected
    def oshi_push(pair, *args)
      host,port = "192.localhost", 8090
      c = TCPSocket.open(host, port)
      c.print({:pair => pair, :args => args}.to_json)
      c.flush
      c.close
    end
 end
end

# javascript in the view.

<% content_for :script do %>
    jQuery(document).ready(function($){
      
      ws = new WebSocket("ws://192.localhost:8080/oshi?user_id=<%= current_user.id %>");
      
      function debug(str){ $("#debug").append("<p>"+str+"</p>"); };

      ws.onopen = function() {
        debug("connected...");
      };
      
      ws.onmessage = function(evt) { 

        $("#message").append("<p>"+evt.data+"</p>"); 
        
      };
      
      ws.onclose = function() { 
        debug("socket closed"); 
      };

    });
<% end %>

#message
#debug