Does Mongoose Actually Validate the Existence of An Object Id? - mongodb

Question

I like the validation that comes with Mongoose. We are trying to figure out whether we want to use it, and put up with the overhead. Does anyone know if providing a reference to the parent collection when creating a mongoose schema, (in the child schema, specify the object id of the parent object as a field,) does this then mean that every time you try to save the document it checks the parent collection for the existence of the refereneced object id?

Answer 1

I'm doing it with middleware, performing a search of the element on validation:
ExampleSchema = new mongoose.Schema({
parentId: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Example'
}
});
ExampleModel = mongoose.model('Example', ExampleSchema);
ExampleSchema.path('parentId').validate(function (value, respond) {
ExampleModel.findOne({_id: value}, function (err, doc) {
if (err || !doc) {
respond(false);
} else {
respond(true);
}
});
}, 'Example non existent');

Answer 2

I'm using mongoose-id-validator. Works good
var mongoose = require('mongoose');
var idValidator = require('mongoose-id-validator');
var ReferencedModel = new mongoose.Schema({name: String});
var MySchema = new mongoose.Schema({
referencedObj : { type: mongoose.Schema.Types.ObjectId, ref: 'ReferencedModel'},
referencedObjArray: [{ type: mongoose.Schema.Types.ObjectId, ref: 'ReferencedModel' }]
});
MySchema.plugin(idValidator);

Answer 3

No, an ObjectId field that's defined in your schema as a reference to another collection is not checked as existing in the referenced collection on a save. You could do it in Mongoose middleware, if needed.

Answer 4

I found this thread very helpful and this is what I came up with:
This Middleware (I think its one anyway please let me know if not) I wrote checks the referenced model for the id provided in the field.
const mongoose = require('mongoose');
module.exports = (value, respond, modelName) => {
return modelName
.countDocuments({ _id: value })
.exec()
.then(function(count) {
return count > 0;
})
.catch(function(err) {
throw err;
});
};
Example model:
const mongoose = require('mongoose');
const uniqueValidator = require('mongoose-unique-validator');
const Schema = mongoose.Schema;
const User = require('./User');
const Cart = require('./Cart');
const refIsValid = require('../middleware/refIsValid');
const orderSchema = new Schema({
name: { type: String, default: Date.now, unique: true },
customerRef: { type: Schema.Types.ObjectId, required: true },
cartRef: { type: Schema.Types.ObjectId, ref: 'Cart', required: true },
total: { type: Number, default: 0 },
city: { type: String, required: true },
street: { type: String, required: true },
deliveryDate: { type: Date, required: true },
dateCreated: { type: Date, default: Date.now() },
ccLastDigits: { type: String, required: true },
});
orderSchema.path('customerRef').validate((value, respond) => {
return refIsValid(value, respond, User);
}, 'Invalid customerRef.');
orderSchema.path('cartRef').validate((value, respond) => {
return refIsValid(value, respond, Cart);
}, 'Invalid cartRef.');
orderSchema.path('ccLastDigits').validate(function(field) {
return field && field.length === 4;
}, 'Invalid ccLastDigits: must be 4 characters');
orderSchema.plugin(uniqueValidator);
module.exports = mongoose.model('order', orderSchema);
I'm a very new dev so any feedback is greatly valued!

Answer 5

You can try https://www.npmjs.com/package/lackey-mongoose-ref-validator (I'm the developer)
It also prevents deletion if the reference is used on another document.
var mongooseRefValidator = require('lackey-mongoose-ref-validator');
mongoSchema.plugin(mongooseRefValidator, {
onDeleteRestrict: ['tags']
});
It's an early version, so some bugs are expected. Just fill in a ticket if you find any.

Answer 6

I know this is an old thread but I had the same problem and I came up with a more "modern" solution.
I'm not an expert myself, hope I'm not misleading anyone, but this seems to work:
for example, in a simple "notes" schema, which contains a user field:
const noteSchema = new Schema({
user: { type: Schema.Types.ObjectId, ref: 'User' },
text: String
});
here's the middleware that checks if the userId exists:
noteSchema.path('user').validate(async (value) => {
return await User.findById(value);
}, 'User does not exist');