node.js - Update array in mongodDB collection -

building api node/express. i'm having problem updating array inside collection mongodb. want add reference id useritems array in collection user.

user looks this:

[     {         fbname: "name.name",         email: "name.name@hotmail.com",         username: "mr.name",         useritems: [objectid("51e101df2914931e7f000003"), objectid("51e101df2914931e7f000005"), objectid("51cd42ba9007d30000000001")]     }]; 

in server.js:

var express = require('express'),     item = require('./routes/items');  var app = express();  app.configure(function () {     app.use(express.logger('dev'));         app.use(express.bodyparser()); });  app.put('/users/:userid/item/:itemid/add', item.adduseritem);  

query:

exports.adduseritem = function(req, res) {     var user = req.params.userid;      var item = req.params.itemid;      console.log('updating useritem user: ' + user);     console.log("item: ", item);      db.collection('users', function(err, collection) {          collection.update({'_id':new bson.objectid(user)}, {$addtoset: { useritems: item}});       }); } 

when try curl nothing happens , error: (52) empty reply server, curl

curl:

curl -i -x put -h 'content-type: applicatio/json' http://127.0.0.1:3000/users/51e6a1116074a10c9c000007/item/51e6a1116074a10c9c000006/add 

try this:

collection.update({'_id':new bson.objectid(user)}, {$addtoset: { useritems: item}}, true, function(err, result){     res.json(200, result); });