Issues getting server-side variable information from MongoDB database using NodeJS with findOne() method

Question

Sorry if this turns out for me to be missing something really obvious, but I've been running into issues with this code for some time and I"m just not getting it. I'm currently trying to work on an authentication system for an app I'm developing for school, and to do that I'm making an API endpoint that takes an inputted password, hashes it, then compares it the stored hashed password to see if the two match. My current code looks like this:

router.route('/auth/').post((req, res) => {
    const userName = req.body.userName;
    const password = User.generateHash(req.body.password);

    let query = User.findOne({"userName": userName},{_id:0, userType:0, fName:0, lName:0, password:1, email:0, userName:0, __v:0});
    let serverpass = query.get("password");

    if (serverpass == password) {
        res.status(200).json("User Authenticated!");
    } else {
        res.status(400).json("Passwords do not match." + password + " " + serverpass)
    }

})

Based on what I read, the findOne() method returns a non-cursorable document you're capable of getting values from using the .get() method. However, whenever I test it using a REST client the serverpass variable always comes back as an object of type Object and the get() method always returns undefined. Any help on this would be appreciated. For reference, here is the database entry I'm trying to read:

  {
    "_id": *REDACTED*,
    "userType": "AuthTest",
    "fName": "Auth",
    "lName": "Test",
    "password": *REDACTED*,
    "email": "[email protected]",
    "userName": "AuthTest",
    "__v": 0
  },

where the password is just "password" hashed. The supplied information to the REST client is:

    {
        "userName":"AuthTest",
        "password":"password"
    }

Thanks!

What is the source for using .get() ? I don't think it will work because Mongo queries are async. This code is synchronous. — tbking
– tbking, Commented Apr 15, 2020 at 20:01
I've seen it a couple places, but one of the ones I still have up is here: journaldev.com/6197/mongodb-findone-example — bombasticmori
– bombasticmori, Commented Apr 15, 2020 at 20:09
that's Java. Also, apart from that the queries are async. They dont return sync response back. Check .exec docs. — tbking
– tbking, Commented Apr 16, 2020 at 9:22

user13278024 · Accepted Answer · 2020-04-15 20:10:55Z

1

MongoDB queries are asynchronous, this means you need to handle the relative Promise. This can be easily achieved with async/await operators.

router.route('your-path').post(async (req, res) => {
   // Get your parameters...

   try {
      const user = await User.findOne(...);

      // TODO: implement your business logic...
   } catch (e) {
      // TODO: error handling...
   }
});

answered Apr 15, 2020 at 20:10

user13278024

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2 Comments

bombasticmori Over a year ago

This got it, thanks a bunch! Still trying to get a handle on whats async/sync.

user13278024 Over a year ago

Happy yo be helpful.

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