Pusher Authentication

pusher_controller.rb

class PusherController < ApplicationController
  protect_from_forgery except: :auth

  def auth
    response = Pusher[params[:channel_name]].authenticate params[:socket_id],
      user_id: params[:id],
      user_info: { name: params[:name] }

    render json: response
  end
end

pusher_initializer.rb

Pusher.app_id = 'YOUR_APP_ID'
Pusher.key = 'YOUR_APP_KEY'
Pusher.secret = 'YOUR_APP_SECRET'

routes.rb

match '/pusher/auth' => 'pusher#auth', via: :post

whos_there.js

var currentUser = {
  name: 'Tommy',
  id: 42
};

var pusher = new Pusher('YOUR_PUSHER_KEY', { 
  authEndpoint: '/pusher/auth',
  auth: {
    params: currentUser
  }
});

var channel = pusher.subscribe('presence-chat');

channel.bind('pusher:subscription_succeeded', function() {
  console.log('Channel members:', channel.members);
});

While implementing this I am getting this error "undefined method `length' for nil:NilClass" what could be this and why it is comming?

I have the same problem as @Ami2810, please help!