Socket is not subsribing

it hard time of me with socket,my connection is establish successfully,but at line of subscribe it is not working. is there any thing, i am missing. i checked everything,i didn't get my mistake

My client side code controller is :

var socket = getSocket($scope);

    var _startSocket = function() { 
      socket.emit('subscribe', 'roomOne');
      socket.on('tx', function(tx) {
        $scope.txs.unshift(tx);
        if (parseInt($scope.txs.length, 10) >= parseInt(TRANSACTION_DISPLAYED, 10)) {
          $scope.txs = $scope.txs.splice(0, TRANSACTION_DISPLAYED);
        }
      });

Service is

var ScopedSocket = function(socket, $rootScope) {
  this.socket = socket;
  this.$rootScope = $rootScope;
  this.listeners = [];
};

ScopedSocket.prototype.removeAllListeners = function(opts) {
  if (!opts) opts = {};
  for (var i = 0; i < this.listeners.length; i++) {
    var details = this.listeners[i];
    if (opts.skipConnect && details.event === 'connect') {
      continue;
    }
    this.socket.removeListener(details.event, details.fn);
  }
  this.listeners = [];
};

ScopedSocket.prototype.on = function(event, callback) {
  var socket = this.socket;
  var $rootScope = this.$rootScope;

  var wrapped_callback = function() {
    var args = arguments;
    $rootScope.$apply(function() {
      callback.apply(socket, args);
    });
  };
  socket.on(event, wrapped_callback);

  this.listeners.push({
    event: event,
    fn: wrapped_callback
  });
};

ScopedSocket.prototype.emit = function(event, data, callback) {
  var socket = this.socket;
  var $rootScope = this.$rootScope;

  socket.emit(event, data, function() {
    console.log("event"+event);
    console.log("data"+data);  
    var args = arguments;
    $rootScope.$apply(function() {
      if (callback) {
        callback.apply(socket, args);
      }
    });
  });
};

angular.module('explorer.socket').factory('getSocket',
  function($rootScope) {
    var socket = io.connect('http://localhost:3001/socket.io/', {
      'reconnect': true,
      'reconnection delay': 500,
    });
    return function(scope) {
      var scopedSocket = new ScopedSocket(socket, $rootScope);
      scope.$on('$destroy', function() {
        scopedSocket.removeAllListeners();
      });
      socket.on('connect', function() {
        scopedSocket.removeAllListeners({
          skipConnect: true
        });
      });
      return scopedSocket;
    };
  });

Server code

module.exports.init = function(io_ext) {
  ios = io_ext;
  if (ios) {
    console.log("socket"+ios);
    // when a new socket connects
    ios.sockets.on('connection', function(socket) {
    console.log("socketconnection"+socket.id);  
      logger.verbose('New connection from ' + socket.id);
      // when it subscribes, make it join the according room
      socket.on('subscribe', function(topic) {
    console.log("subscribe"+JSON.stringif(topic));  
        logger.debug('subscribe to ' + topic);
        socket.join(topic);
        socket.emit('subscribed');
      });

      // disconnect handler
      socket.on('disconnect', function() {
        logger.verbose('disconnected ' + socket.id);
      });

    });
  }
  return ios;
};