gistfile1.rb

require 'rubygems'
require 'em-websocket'
require 'em-mongo'
require 'json'
require 'geokit'
require 'digest/md5'

chat_messages = []

@@session_time_out = 60 * 10
@@salt = "create-your-salt-here"

EventMachine.run {
  @channel = EM::Channel.new
  @collection
  
  @db = EM::Mongo::Connection.new.db('database-name')
  @message_collection = @db.collection('messages')
  @session_collection = @db.collection('sessions')
  @user_collection = @db.collection('users')
       
  EventMachine::WebSocket.start(:host => "0.0.0.0", :port => 2000, :debug => false) do |ws|
    
    def send(ws, msg)
      puts msg
      ws.send(msg)
    end
    
    def send_session_id(ws, msg_dict)
      now = Time.now
      # Search for a session
       @session_collection.find({"username" => msg_dict['payload']['username'], 'time' => {'$gte' => now - @@session_time_out}}) do |res|
         session_id = ""
         
         # If no session was found, create one! 
         if res.count == 0
           session_id = Digest::MD5.hexdigest(@@salt + Time.now.to_s + msg_dict['payload']['username'] + @@salt)
           session_dict = {'username' => msg_dict['payload']['username'], 'session_id' => session_id, 'time' => now}
           @session_collection.insert(session_dict)
        
         # Else, recycle the last one
         else
           session_id = res[0]['session_id']
         end
         
         send ws, ({'action' => 'authenticate', 'status' => {'code' => 200, 'message' => 'Authentication successful'}, 'payload' => {'session_id' => session_id}}.to_json)
       end
    end
    
    def authenticate(ws, msg_dict)  
      # Find given user in database
       @user_collection.find({"username" => msg_dict['payload']['username']}) do |res|
         fail = false
         # If no users where found with the given username
         if res.count == 0
           puts "No results!"
           fail = true
         end
         
          # If a user was found with the given username, check password
         if !fail
           user = res[0]
           if msg_dict['payload']['password'] != user["password"]
             fail = true
           end
         end
         
         # If authentication failed, send error message
         if fail
           send ws, ({'action' => 'authenticate', 'status' => {'code' => 401, 'message' => 'User / Pass combination not valid'}}.to_json)
           ws.unbind
        
         # If success! :D
         else
           send_session_id ws, msg_dict
         end
       end
    end
    
    def create_dict_from_payload(payload, keys, add_time=true)
      dict = {}
      keys.each do |key|
        dict[key] = payload[key]
      end
      if add_time
        dict['time'] = Time.now
      end
      return dict
    end
    
    def send_session_expired_error(ws)
      send ws, ({'action' => 'authenticate', 'status' => {'code' => 401, 'message' => 'Session ID not valid or expired'}}.to_json)
    end
    
    def send_message(ws, msg_dict)
      now = Time.now
      payload = msg_dict['payload']
      @session_collection.find({"username" => payload['username'], "session_id" => payload['session_id'], 'time' => {'$gte' => now - @@session_time_out}}) do |res|
        if res.count == 0
          send_session_expired_error
        else
          @message_collection.insert(create_dict_from_payload(payload, ['message', 'location', 'session_id', 'username', 'to_username']))
          send ws, ({'action' => 'message', 'status' => {'code' => 200}}.to_json)
          @channel.push({'action' => 'message_push', 'payload' => create_dict_from_payload(payload, ['message', 'location', 'username', 'to_username'])}.to_json)
        end
      end
    end
    
    def buffer(ws, msg_dict)
      payload = msg_dict['payload']
      now = Time.now
       @session_collection.find({"username" => payload['username'], "session_id" => payload['session_id'], 'time' => {'$gte' => now - @@session_time_out}}) do |res|
         if res.count == 0
           send_session_expired_error
         else
           @message_collection.find({}) do |res|
             mes_array = []
             res.each {|message| mes_array << message}
             dict = {'action' => 'buffer', 'status' => {'code' => 200}, 'payload' => {'messages' => mes_array}} 
             send ws, dict.to_json
           end
        end
      end
    end
    
    ws.onopen {
      sid = @channel.subscribe { |msg| ws.send msg }
   
      ws.onmessage { |msg|
        msg_dict = JSON.parse msg
        puts msg_dict
        case msg_dict['action']
        
        # Authenticate
        when "authenticate"
          puts "Authentication request"
          begin
            authenticate ws, msg_dict
          rescue Exception => e
            puts e
          end
        
        # Message
        when "message"
          puts "Message request"
          begin
            send_message ws, msg_dict
          rescue Exception => e
            puts e
          end
        
        # Buffer
        when "buffer"
          puts "Buffer request"
          begin
            buffer ws, msg_dict            
          rescue Exception => e
            puts e
          end
          
        else
          puts "Something else"
        end
    }

    ws.onclose {
      @channel.unsubscribe(sid)
    }
  }
    
  end
  
 # use the following command to create a user in the MongoDB databaes
 # @user_collection.insert ({'username' => 'baron', 'password' => Digest::MD5.hexdigest('christmas')})

  puts "Server started"
}