@fastify/mongodb NPM

@fastify/mongodb

Fastify MongoDB connection plugin; with this you can share the same MongoDB connection pool in every part of your server.

Under the hood the official MongoDB driver is used, the options that you pass to register will be passed to the Mongo client. The mongodb driver is v6.x.x.

If you do not provide the client by yourself (see below), the URL option is required.

Install

npm i @fastify/mongodb

Usage

Add it to your project with register and you are done!

const fastify = require('fastify')()

fastify.register(require('@fastify/mongodb'), {
  // force to close the mongodb connection when app stopped
  // the default value is false
  forceClose: true,

  url: 'mongodb://mongo/mydb'
})

fastify.get('/user/:id', async function (req, reply) {
  // Or this.mongo.client.db('mydb').collection('users')
  const users = this.mongo.db.collection('users')

  // if the id is an ObjectId format, you need to create a new ObjectId
  const id = new this.mongo.ObjectId(req.params.id)
  try {
    const user = await users.findOne({ id })
    return user
  } catch (err) {
    return err
  }
})

fastify.listen({ port: 3000 }, err => {
  if (err) throw err
})

You may also supply a pre-configured instance of mongodb.MongoClient:

const mongodb = require('mongodb')
mongodb.MongoClient.connect('mongodb://mongo/db')
  .then((client) => {
    const fastify = require('fastify')()

    fastify.register(require('@fastify/mongodb'), { client: client })
      .register(function (fastify, opts, next) {
        const db = fastify.mongo.client.db('mydb')
        // ...
        // ...
        // ...
        next()
      })
  })
  .catch((err) => {
    throw err
  })

Notes:

the passed client connection will not be closed when the Fastify server shuts down.
to terminate the MongoDB connection you have to manually call the fastify.close method (for example for testing purposes, otherwise the test will hang).
mongodb connection timeout is reduced from 30s (default) to 7.5s to throw an error before fastify plugin timeout.

Reference

This plugin decorates the fastify instance with a mongo object. That object has the following properties:

client is the MongoClient instance
ObjectId is the ObjectId class
db is the DB instance

The ObjectId class can also be directly imported from the plugin as it gets re-exported from mongodb:

const { ObjectId } = require('@fastify/mongodb')

const id = new ObjectId('some-id-here')

The db property is added only if:

a database string option is given during the plugin registration.
the connection string contains the database name. See the Connection String URI Format

A name option can be used to connect to multiple MongoDB clusters.

const fastify = require('fastify')()

fastify
  .register(require('@fastify/mongodb'), { url: 'mongodb://mongo1/mydb', name: 'MONGO1' })
  .register(require('@fastify/mongodb'), { url: 'mongodb://mongo2/otherdb', name: 'MONGO2' })

fastify.get('/', function (req, res) {
  // This collection comes from "mongodb://mongo1/mydb"
  const coll1 = this.mongo.MONGO1.db.collection('my_collection')
  // This collection comes from "mongodb://mongo2/otherdb"
  const coll2 = this.mongo.MONGO2.db.collection('my_collection')
  // ...
  // ...
  // do your stuff here
  // ...
  // ...
  res.send(yourResult)
})