A simple chat with Juggernaut

Dec 03

Posted by Sandro Paganotti in Ruby on Rails - comments are closed

PUSH technology has ever been a sort of Chimera for web developers. Finally, in the last year, a bounch of solutions emerged from skilled developers; one of them, strictly related with the Rails world, was Juggernaut

How does this work ?

Juggernaut automatically includes a small .swf in the user page that keeps open a socket with a special push server included in the plugin . After registering the user to one (or more) specific channels with the variable ‘session[:juggernaut_channels]’, you can send a broadcast message through those channels by using the send_data function that accepts a javascript code as parameter:


 Juggernaut.send_data(data, session[:juggernaut_channels])

Wow, pretty cool isn’t it ?

Now let’s go further and create a small chat using Juggernaut (following the instructions in the README FILE )


gem install json
gem install eventmachine
rails chat_demo
cd chat_demo
ruby script/plugin install http://juggernaut.rubyforge.org/svn/trunk/juggernaut/
ruby script/generate controller chat

Now open the controller’s file and write:


class ChatController < ApplicationController

  def index
    session[:juggernaut_channels] = ["chat_channel"]
  end

  def send_data
    input_data = CGI.escapeHTML(params[:chat_input])
    data = "new Insertion.Top('chat_data', '<li>#{input_data}</li>');" 
    Juggernaut.send_data(data, session[:juggernaut_channels])
    render :nothing => true
  end

Last, open index.rhtml in views/chat and write:


<html>
  <head>
    <%= javascript_include_tag :defaults %>
    <%= listen_to_juggernaut_channels :chat_channel %>
  </head>
  <body>
    <%= form_remote_tag(
          :url => { :action => :send_data },
          :complete => "$('chat_input').value = ''" ) %>
      <%= text_field_tag( 'chat_input', '', { :size => 20, :id => 'chat_input'} ) %>
      <%= submit_tag "Add" %>
    </form>
    <ul id="chat_data" style="list-style:none">
    </ul>
  </body>
</html>

Ok. Done :) Now we just need to start the push server (no extra juggernaut configuration is needed for this sample) and then run the standard server with these commands:


ruby script/push_server # ( for me it worked only when launched with root user)
ruby script/server

Now open a browser, surf to 0.0.0.0:3000 and enjoy your first Juggernaut creation !

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