Mongoose Populate returns an empty array

Question

I get an empty array with the following code:

var mongoose = require('mongoose');
var db = mongoose.createConnection('localhost', 'mytestapp');

var SurveySchema = require('../models/Survey.js').SurveySchema;
var Survey = mongoose.model('SurveySchema', SurveySchema, 'surveys');


var UserSchema = require('../models/Survey.js').User;
var User = mongoose.model('user', UserSchema, 'users');

exports.getSurveysForUser = function(User) {
    return function (req, res) {


 User
        .findOne({_id: req.params.userId})
        .populate('surveys')
        .exec(function (err, user){
            if (err) return res.json({error: err})
            else {
                var surveyList=[];
                surveyList = user.surveys;
                console.log(surveyList);
                console.log("user: "+ user);
                res.json(surveyList);

            }
        });
}};

This is the console output:

 [ ]

user: { __v: 2,
  _id: 52939b8c22a7efb720000003,
  email: '[e-mail]',
  password: '202cb962ac59075b964b07152d234b70',
  surveys: []
}

These are the Mongoose models:

exports.SurveySchema = new Mongoose.Schema({
description : String,
questions : [question] });

exports.User = new Mongoose.Schema({
name : String,
email: { type: String, unique: true },
password: { type: String, required: true},
surveys :  [{type: Schema.ObjectId, ref: 'SurveySchema'}] });

Btw:

I already tried User.findOne (...) and then Survey.find () in the callback. It seemed that the second statement was not even fulfilled. Apparently, I am very new to mongoose .. and I cannot find a way to solve this problem.

Do you have any ideas how to help me? I could not find any useful solution here, but the problem should not be big. Thanks in advance, it really holds me back for a few days!

Edit: this is index.js using the method:

var mongoose = require('mongoose');
var db = mongoose.createConnection('localhost', 'mytestapp');

var SurveySchema = require('../models/Survey.js').SurveySchema;
var Survey = mongoose.model('SurveySchema', SurveySchema, 'surveys');



var UserSchema = require('../models/Survey.js').User;
var User = mongoose.model('user', UserSchema, 'users');

//.. here are some more methods.. 

exports.getSurveysForUser = function(User) {
return function (req, res) {
 User
            .findOne({_id: req.params.userId})
            .populate('surveys')
            .exec(function (err, user){
                if (err) return res.json({error: err})
                else {
                    var surveyList=[];
                    surveyList = user.surveys;
                    console.log(surveyList);
                    console.log("user: "+ user);
                    res.json(surveyList);

                }
            });
}};

//this is the code, that saves a response to a survey

exports.addResponse = function(ResponseSet) {
    return function (req, res) {
        console.log("bin da: addResponse");
        console.log("response zu: " + req.body.surveyId);
        console.log("von user : " + req.body.userId);

        //für user speichern

        var pUser = User.findOne({_id:req.body.userId}, function (error, user) {

                // Maybe populate doesnt work, because i only push the ID?

               user.surveys.push(Mongoose.Types.ObjectId(req.body.surveyId));

               user.save();

            }
        );



        var pSurvey = Survey.findOne({_id:req.body.surveyId}, function (error, survey) {
                survey.responses.push(Mongoose.Types.ObjectId(req.params.id));
                survey.save();
            }
        );



        //responseSet speichern

        var responseSet = new ResponseSet(req.body);
        responseSet.save(function(error, responseSet) {
            if (error || !responseSet) {
                res.json({ error : error });
            } else {

                res.json(responseSet);
            }
        });
    };

 };

And this is the app.js application that consumes index.js:

var Mongoose = require('mongoose');
var db = Mongoose.createConnection('localhost', 'mytestapp');

var SurveySchema = require('./models/Survey.js').SurveySchema;
var Survey = db.model('surveys', SurveySchema);
var UserSchema = require('./models/Survey.js').User;
var User = db.model('user', UserSchema);

var ResponseSetSchema = require ('./models/Survey.js').responseSet;
var ResponseSet = db.model('responseSet', ResponseSetSchema);

var express = require('express')
  , routes = require('./routes')
  , http = require('http')
  , path = require('path')
  , passport = require('passport')
  , pass = require('./config/pass')

  , user_routes = require('./routes/user');

var app = express();

// all environments
app.set('port', process.env.PORT || 3000);
app.set('views', __dirname + '/views/app');
//app.engine('html', require('ejs').renderFile);
app.use(express.static(__dirname + '/views/app'));
app.use(express.cookieParser());
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(express.session({ secret: 'securedsession' }));
app.use(passport.initialize()); // Add passport initialization
app.use(passport.session()); // Add passport initialization
app.use(app.router);
app.use(express.static(path.join(__dirname, 'public')));

// development only
if ('development' == app.get('env')) {
  app.use(express.errorHandler());
}

app.all('/secure', pass.ensureAuthenticated);


app.get('/', function (req, res)
{
    res.render('index.html');
} );

// some more code... 

app.get('/api/secure/userSurveys/:userId', routes.getSurveysForUser(User));

http.createServer(app).listen(app.get('port'), function(){
  console.log('Express server listening on port ' + app.get('port'));
});

Hope this helps to deal with the problem! Thanks a lot in advance! :)

Answer 1

:

surveys: [{type: Schema.ObjectId, ref: 'SurveySchema'}] });

surveys: [{type: Schema.Types.ObjectId, ref: 'SurveySchema'}] });

, , , , User.surveys.

http://mongoosejs.com/docs/populate.html, :

, aaron, . , "" aaron.stories. "

, :

exports.getSurveysForUser = function(User) {
...
};

var . :

exports.getSurveysForUser = (function(User) {
...
})(User);

User, .

index.js

app.get('/api/secure/userSurveys/:userId', routes.getSurveysForUser(User));

app.get('/api/secure/userSurveys/:userId', routes.getSurveysForUser());

. , . . !

Answer 2

, ! -, , .

, mongoose.model('modelname', schemaname); , mongoose.model(...) index.js.

-, : user.surveys testuser! , . , . , . . , mongodb → ! user.surveys ! , - . , .

, export.addResponse(....) , user.surveys survey.responses. , , - .

, !