Examples

class IvrController < ApplicationController
  # We use just a little Ruby magic to generate get_ and set_ methods so we
  # can easier access the session object, where our state machine keeps its
  # state. This is optional, but it'll let you say set_something(7) instead of
  # session['something'] = 7, and get_something instead of
  # session['something'].
  def self.session_variables(*vars)

    vars.each do |var|
      define_method('get_'+var.to_s) { session[var] }
      define_method('set_'+var.to_s) { |value| session[var] = value }
    end

  end

  session_variables :tries, :extno, :next_step

  # The main method of the state machine
  def state_machine

    if get_next_step.nil?
      render :text => ''
    else

      eval(get_next_step.split(' ').first)
    end
  end

  # Reset the state machine to its initial state
  def reset
    set_next_step 'say_welcome'
    render :text => 'state machine reset' # ignored by Liverpie anyway

  end


  private


  #
  # IVR / State Machine steps below
  #


  def say_welcome
    set_tries 1
    set_extno nil

    msg = send_msg 'playback', 'ivr/8000/ivr-welcome_to_freeswitch.wav', true

    fs_render msg, 'event_name', 'CHANNEL_EXECUTE_COMPLETE'

    set_next_step 'askfor_extno'
  end

  def askfor_extno

    if get_tries > 3
      hangup
    else
      msg = send_msg "read", "0 10 ivr/8000/ivr-enter_ext.wav extno 10000 #,*"

      fs_render msg, 'event_name', 'CHANNEL_EXECUTE_COMPLETE'
      set_next_step 'read_extno'
    end
  end

  def read_extno

    session[:tries] += 1
    set_extno params['variable_extno']
    logger.info "EXTENSION NUMBER: #{get_extno}"

    fs_render 'api sleep 1', 'content_type', 'api/response' # sorta noop

    if get_extno.to_s.empty?

      set_next_step 'askfor_extno'
    else
      set_next_step 'hangup'
    end
  end


  def hangup
    uuid = params['unique_id'].to_s
    msg  = "SendMsg #{uuid}\ncall-command: hangup\n"

    msg << "hangup-cause: SERVICE_NOT_IMPLEMENTED"
    fs_render msg, 'event_name', 'CHANNEL_EXECUTE_COMPLETE'
    set_next_step nil
  end




  #
  # Methods specific to FreeSWITCH below
  #

  def send_msg(app, pars, blocking=true)

    uuid = params['unique_id'].to_s
    msg = "SendMsg #{uuid}\ncall-command: execute\nexecute-app-name: #{app}"

    msg << "\nexecute-app-arg: #{pars}"
    msg << "\nevent-lock:true" if blocking    
  end

  def fs_render(msg, expected_key, expected_value)
    hash = { 'msg' => msg.to_s, 
             'expected_key' => expected_key,
             'expected_value' => expected_value }
    render :text => hash.to_yaml

  end

end
					
				

public class IVRServlet extends HttpServlet {

@Override

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.getWriter().write("reset"); // not needed though

    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String uuid = StringUtils.trimToEmpty(request.getParameter("unique_id"));
        String extNo = StringUtils.trimToEmpty(request.getParameter("variable_extno"));
        HttpSession session = request.getSession();

        String responseStr = null;
        if (session.getAttribute("next-step") == null) {
            responseStr = sayWelcome(uuid, session);
        } else if (((String) session.getAttribute("next-step")).equals("askForExt")) {
            responseStr = askForExt(uuid, session);
        } else if (((String) session.getAttribute("next-step")).equals("readExt")) {
            responseStr = readExt(extNo, session);
        } else if (((String) session.getAttribute("next-step")).equals("hangup")) {
            responseStr = hangup(uuid, session);
        }
        System.out.println(responseStr); // to print the yaml to console

        response.getWriter().print(responseStr);
        response.getWriter().flush();

    }


    String sayWelcome(String uuid, HttpSession session) {
        session.setAttribute("tries", 1);
        session.setAttribute("extNo", null);
        session.setAttribute("next-step", "askForExt");

        String msg = createMessage(uuid, "playback", "ivr/8000/ivr-welcome_to_freeswitch.wav");
        return formatMessageToYaml(msg, "event_name", "CHANNEL_EXECUTE_COMPLETE");

    }


    String askForExt(String uuid, HttpSession session) {
        Integer tries = (Integer) session.getAttribute("tries");
        if (tries > 3) {
            return hangup(uuid, session);
        } else {
            session.setAttribute("next-step", "readExt");
            String msg = createMessage(uuid, "read", "0 10 ivr/8000/ivr-enter_ext.wav extno 10000 #,*");
            return formatMessageToYaml(msg, "event_name", "CHANNEL_EXECUTE_COMPLETE");
        }
    }


    String readExt(String extNo, HttpSession session) {
        Integer tries = (Integer) session.getAttribute("tries") + 1;
        session.setAttribute("tries", tries);
        session.setAttribute("extNo", extNo);

        if (StringUtils.isBlank(extNo)) {
            session.setAttribute("next-step", "askForExt");
        } else {
            session.setAttribute("next-step", "hangup");
        }

        return formatMessageToYaml("api sleep 1", "content_type", "api/response");
    }


    String hangup(String uuid, HttpSession session) {
        session.setAttribute("next-step", null);
        String msg = "SendMsg " + uuid + "\n call-command: hangup\n hangup-cause: SERVICE_NOT_IMPLEMENTED";
        return formatMessageToYaml(msg, "event_name", "CHANNEL_EXECUTE_COMPLETE");
    }


    private String createMessage(String uuid, String app, String args) {
        return "SendMsg " + StringUtils.trimToEmpty(uuid) + "\n call-command: execute \n " +

                "execute-app-name: " + app + "\n execute-app-arg: " + args + "\n event-lock: true";
    }


    private String formatMessageToYaml(String msg, String expectKey, String expectValue) {
        return "---\nmsg: |- \n " + msg + "\nexpected_key: " + expectKey + "\nexpected_value: " + expectValue;
    }
}