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.

[Souvik Kar Mahapatra]

On changes in any JS file other than the models gives error: Cannot overwriteUsermodel once compiled. at Mongoose.model next js since during hot reload as there are no changes in the model file so the previously compiled one is used (cached).
In case someone is facing such issue can fix this in following way:

global.User = global.User || mongoose.model("User", userSchema);

export default global.User;

[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.

[Daniel Gadd]

Hi

Getting errors with getServerSideProps, which is an important example you left out. For a time it worked until recently. When I import a scheme on a page I get a t.version error and others.

Do you know the correct, error free way at importing a scheme on a page for use with getServerSideProps ?

Thanks

Daniel

[Raphael Chaula]

Hi, can you share the snippet or your code please!
It will be easier for me to understand the issue and help you.

[Daniel Gadd]

Wow - Didn't see this until now. Playing around and got through it but when it pops up again I'll try make a tiny empty project to show example. I did recently update Node and NextJS so maybe not see again :)

[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/...

[vicwildcode]

HI, thanks for the tutorial, i have a question, what about connecting 2 different folders, one containing front project, and second containint backend made with Mongodb, mongoose and node? i cannot find this anywhere , thanks if anybody can help with this

[Raphael Chaula]

Hi, By default next.js supports API routes nextjs.org/docs/api-routes/introdu... you can start with that link, they are inside /pages/api folder.

But you can create your own server (custom) and decide for yourself how you want your directory structure to be here nextjs.org/docs/advanced-features/...

Thanks

[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 = {};

[Gabriel]

import mongoose from 'mongoose';
import { BookDocument } from './book.interface';
import { BookSchema } from './book.schema';

export const BookModel = mongoose.models.Book || mongoose.model<BookDocument>('Book', BookSchema);
export default BookModel;

I think this is a better way.

[Raphael Chaula]

You are welcome.

[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!!!!

[BOUANANI YASSER]

Very helpful sir, thanks a lot.

[Raphael Chaula]

You're welcome