Select fields based on permission field - mongodb

Question

Hello guys i am having a problem getting from database only fields that are permitted by the user.
So my schema is:
var profileSchema = mongoose.Schema({
authId: {type: Schema.Types.ObjectId, ref: 'Auth'},
fname: String,
lname: String,
am: Number,
email: String,
location: String,
languages: [String],
birth_date: {
type: Date,
default: Date.now
},
reg_date: {
type: Date,
default: Date.now
},
last_log: {
type: Date,
default: Date.now
},
permissions: {
location: {type: Boolean,Default:true},
birth_date: {type: Boolean,Default:true},
email: {type: Boolean,Default:true},
am: {type: Boolean,Default:true},
subjects: {type: Boolean,Default:true},
files: {type: Boolean,Default:true},
posts: {type: Boolean,Default:true}
},
ip: String,
subjects: [{type: Schema.Types.ObjectId, ref: 'Subject'}],
files: [{type: Schema.Types.ObjectId, ref: 'FileIndex'}],
posts: [{type: Schema.Types.ObjectId, ref: 'Post'}],
notifications: [{type: Schema.Types.ObjectId, ref: 'Notifications'}]
});
And I am trying to get only fields that in permission field have true which means it's permitted. So I am running the following query :
database.Profile.findOne({_id: req.params.id}).exec(function (err, profile) {
console.log(profile);
res.send(profile);
});
How do I select only the fields that are permitted?

Answer 1

Try this, It ,might get you what you want:
database.Profile.findOne({_id: req.params.id},{location:$.permissions.location , birth_date:$.permissions.birth_date, email:$.permissions.email, am:$.permissions.am, subjects:$.permissions.subjects, files:$.permissions.files, posts:$.permissions.posts}).exec(function (err, profile) {
console.log(profile);
res.send(profile);
});

Answer 2

You could do a query with the lean() method chained since documents returned from queries with the lean option enabled are plain javascript objects, not MongooseDocuments and manipulate the object returned by removing the keys as determined by the permissions object fields:
Object.filter = function( obj, predicate) {
var result = {}, key;
for (key in obj) {
if (obj.hasOwnProperty(key) && !predicate(obj[key])) {
result[key] = obj[key];
}
}
return result;
};
database.Profile.findOne({_id: req.params.id}).lean().exec(function (err, doc) {
if (err) return handleError(err);
console.log(doc);
console.log(doc.permissions);
var filtered = Object.filter(doc.permissions,
function (key){ return doc.permissions[key]; }
);
console.log(filtered);
res.send(filtered);
});
Another alternative that uses the Mongoose's projection select() method would be to make two queries; the first one will return the whole document and the next will query the same document but project the fields based on the permissions object fields:
The following shows this:
database.Profile.findOne({_id: req.params.id}).lean().exec(function (err, doc) {
console.log(doc);
console.log(doc.permissions);
var projection = Object.keys(doc.permissions)
.filter(function (key){ return doc.permissions[key]; })
.join(' ');
console.log(projection);
database.Profile.findOne({_id: req.params.id})
.select(projection)
.exec(function (err, profile) {
if (err) return handleError(err);
res.send(profile);
});
});