Rake task to communicate with a faye server and provide connectivity to it's application container

remote_shell_agent.rake

namespace :remote_shell_agent do

  module Faye

    class Transport::Http < Transport
      def request(envelopes)

        content = encode(envelopes)
        params  = build_params(@endpoint, content)
        request = create_request(params)

        request.callback do
          handle_response(request.response, envelopes)
          store_cookies(request.response_header['SET_COOKIE'])
        end

        request.errback do
          handle_error(envelopes)
        end
      end

    private 

      def handle_response(response, envelopes)
        message = MultiJson.load(response) rescue nil
        if message
          receive(envelopes, message)
        else
          handle_error(envelopes)
        end
      end

    end
  end

  desc "Listen for tasks to execute"

    task :listen => :environment do

    require 'eventmachine'
    require 'stringio'
    require 'zlib'
    require 'base64'
    require 'json'

      EM.run {

        def eval_ruby(command)
          template = <<-EOS
            begin 
              $stdout = StringIO.new
              #{command}
    
              $stdout.string
            rescue Exception => e
              e.to_s
            ensure 
              $stdout = STDOUT
            end
          EOS

          eval(template)
        end

        client = Faye::Client.new('https://faye-dh.cfapps.io')

        app = JSON.parse(ENV['VCAP_APPLICATION']);
        guid = "#{app['application_version']}/#{app['instance_index']}"

        client.subscribe("/commands/#{guid}") do |command|
          console_type = command['console_type']
          command_text = command['command']

          result = ''

          if (console_type == 'ruby')
            result = eval_ruby(command_text)
          else
            result = `#{command_text} 2>&1`
          end
          
          compressed = Zlib::Deflate.deflate(result)
          enc = Base64.encode64(compressed)

          publication = client.publish("/responses/#{guid}", 'text' => enc)

        end

      }

    end

end