Data model reference using ObjectID in Mongoose - node.js

Question

I have two mongoose models users and requests. One user can have multiple requests. To link these two data models, I am referencing the objectID of the user in the Request model. However when I am trying to fetch all the requests for a particular user ID, I don't get any result.
Users
var UserSchema = new Schema({
name: String,
username: String
});
module.exports = mongoose.model('User', UserSchema);
Requests
var RequestSchema = new Schema({
type: String,
user_id: { type : mongoose.Schema.Types.ObjectId, ref: 'User'}
});
module.exports = mongoose.model('Request', RequestSchema);
Below is the sample code which fetches the requests based on the User ID passed in the URL
exports.getRequests = function (req, res, next) {
var userId = req.params.id;
console.log('USER ID'+userId);
Request.findOne({'user_id': 'kenan'}, function (err, request) {
if (err) return next(err);
if (!requests){
console.log('NO REQUEST FOUND');
return res.send(401);
}
res.json(request);
});
};
I know I am using findOne which will return me a single resource. However this is failing and I am not getting any result. I have in my DB the data populated. Below is the URL for fetching the requests.
http://localhost:9000/api/V1/users/547ee1e82e47bb982e36e433/requests
Please help suggest as to what I am doing wrong over here.
Thanks

Answer 1

You need to populate the references to the users once you do a find().
Once you find all the requests, you need to resolve the references to
the users. Use populate to resolve the references.
After resolving, filter the requests based on the name that you
are searching for.
Updated Code:
Request
.find().populate({'path':'user_id',match:{'name':'kenan'}})
.exec(function (err, resp) {
var result = resp.filter(function(i){
return i.user_id != null;
});
console.log(result);
})

Answer 2

OK, the above answer is correct and thanks for your response. I incorrectly populated my Requests collection. This is just for every one's else knowledge. When you have a Object ID reference as one of the fields in the collection then make sure that you are inserting the ObjectID object instead of just the numerical value.
Wrong
{ "_id" : ObjectId("54803ae43b73bd8428269da3"), "user_id" : "547ee1e82e
47bb982e36e433", "name" : "Test", "service_type" : "test", "version" : "10"
, "environment" : "test", "status" : "OK", "__v" : 0 }
Correct
{ "_id" : ObjectId("54803ae43b73bd8428269da3"), "user_id" : ObjectId("547ee1e82e
47bb982e36e433"), "name" : "test", "service_type" : "test", "version" : "10"
, "environment" : "test", "status" : "OK", "__v" : 0 }