Adding MongoDB (Mongoose) to Next.js APIs

After you have created a Next.js app, install mongoose yarn add mongoose then create next.config.js at the root directory of your app if it doesn't exist and in it add your MongoDB connection url string.

next.config.js

module.exports = {
    env: {
        mongodburl: "Your MongoDB connection String",
    }
};

Then create a MongoDB connect middleware that will be called to create a new connection to DB or reuse the existing one whenever we do an operation to DB, in my case I added middleware folder in the root directory of the app and added it there.

middleware/mongodb.js

import mongoose from 'mongoose';

const connectDB = handler => async (req, res) => {
  if (mongoose.connections[0].readyState) {
    // Use current db connection
    return handler(req, res);
  }
  // Use new db connection
  await mongoose.connect(process.env.mongodburl, {
    useUnifiedTopology: true,
    useFindAndModify: false,
    useCreateIndex: true,
    useNewUrlParser: true
  });
  return handler(req, res);
};

export default connectDB;

Then create your models, in my case I added models folder in root directory of the app and created a User model in it.

models/user.js

import mongoose from 'mongoose';
var Schema = mongoose.Schema;

var user = new Schema({
  name: {
    type: String,
    required: true
  },
  email: {
    type: String,
    required: true
  },
  password: {
    type: String,
    required: true
  },
  since: {
    type: Date,
    default: Date.now
  }
});

mongoose.models = {};

var User = mongoose.model('User', user);

export default User;

Then lets create an api for user and add create a new user functionality in it in the pages/api/user directory.

pages/api/user.js

import connectDB from '../../middleware/mongodb';
import bcrypt from '../../middleware/bcrypt';
import User from '../../models/user';

const handler = async (req, res) => {
  if (req.method === 'POST') {
    // Check if name, email or password is provided
    const { name, email, password } = req.body;
    if (name && email && password) {
        try {
          // Hash password to store it in DB
          var passwordhash = await bcrypt.sign(password);
          var user = new User({
            name,
            email,
            password: passwordhash,
          });
          // Create new user
          var usercreated = await user.save();
          return res.status(200).send(usercreated);
        } catch (error) {
          return res.status(500).send(error.message);
        }
      } else {
        res.status(422).send('data_incomplete');
      }
  } else {
    res.status(422).send('req_method_not_supported');
  }
};

export default connectDB(handler);

We are done here, just make a post request to http://localhost:3000/api/user in the request body include: name email and password you will get a response either user object if user is created successfully or an error message if something went wrong.

Happy Hacking!

Comments

[Nasiruddin Saiyed]

Well explained, +1, but it will not work if we are exporting next project into static site using next export. [nextjs.org/docs/api-routes/introdu...]

dev-to-uploads.s3.amazonaws.com/i/...

[Raphael Chaula]

Yes, API routes only work server side (Lambdas) in Next.js.

[Tobias Nickel]

nice, thanks, never used next, but wanted to know how APIs are done with it. However I looked some more into the official docunentation.

It loojs very straight forward. 👍

[Raphael Chaula]

You're welcome.

[Regisnut]

Hi, can you precise if I host the website on vercel, if mongodb will be on vercel too? or do I need to host it on heroku as an example?
thanks

[Raphael Chaula]

You can host the website on vercel, it will work just fine, I used MongoDB Atlas, so you can host MongoDB anywhere.

Here is what you should not do;
Don't export the Next.js app, it has to be server side.

[Regisnut]

Ouah, nice to hear ! I will use MongoDB atlas too with mongoose.
But I'm still a noob, I don't know what is export a Next.js App?

[Raphael Chaula]

Export is when you want to build a Next.js app into static HTML file.
You can read more about it here nextjs.org/docs/advanced-features/...

[Federico Cingerle]

Hi! do you have a github repo with this explanation? If you have it, could you share it?

[Raphael Chaula]

I don't have any repo specifically to that article but here is a project similar, you can check it out, github.com/raphaelchaula/joinshift... , it is a Next.js project with Mongoose and MongoDB.

[Federico Cingerle]

Thanks very much!!!!

[Robert Megens]

Thanks very much. NextJS seemingly rebuilds my User model at each page call, so this line saved me a persistent overwrite warning error:

mongoose.models = {};

[Raphael Chaula]

You are welcome.