Nodejs function is working only once

I have a function called UpdateDocument.js and I have to run this function when I do request. It's only running once. After first request, it's not updating document. I have to refresh page but this is not why I want.

I'm requesting from client side and running function in server side.

socket.emit('UpdateDocumentRequest', ....);

UpdateDocument.js :

var users  = require('./datas/user');    
exports.UpdateDocument = function(app, passport, io) {   
io.on('connection', function(socket){ 
  socket.on('UpdateDocumentRequest', function(data) {
         //console.log(data);
        socket.emit('UpdateDocumentRequest__return', { last_balance: last_balance });

        var query = {....};
        users.update(query, { ...},   function (err, statu) { 
    });

});
}

In server.js

UpdateDocument.UpdateDocument(app, passport, io);

Console : As you can see, they have different dates.

{ user: '',
  btc_balance: '0.00008630',
  betAmount: '0.00000002',
  betPayout: '2',
  betProfit: '0.00000002',
  betTime: '2014-08-24T05:17:45.328Z' }
{ user: '',
  btc_balance: '0.00008630',
  betAmount: '0.00000002',
  betPayout: '2',
  betProfit: '0.00000002',
  betTime: '2014-08-24T05:17:47.225Z' }

{ user: '',
  btc_balance: '0.00008630',
  betAmount: '0.00000002',
  betPayout: '2',
  betProfit: '0.00000002',
  betTime: '2014-08-24T05:17:49.871Z' }