Based on serve-static

Tested on node 10.x, npm 6.x

Require node-mongodb-native 3.x

$ npm i serve-gridfs

import serveGridfs from 'serve-gridfs'

Create a new middleware function to serve files from a mongodb gridfs collection. The file to be served is based on req.url. In a default setting, when a file is not found, this middleware call next(), instead of returning 404, to be in line with the express serve-static middleware.

Internally, this middleware use promised based mongo client, so pass in the connection detail here.

const mongoConnection = MongoClient.connect('mongodb://localhost:27017/myApp')

All options are optional

// with express js

import express from 'express'
import { MongoClient, GridFSBucket } from 'mongodb'
import serveGridfs from 'serve-gridfs'

const app = express()
const mongoConnection = MongoClient.connect('mongodb://localhost:27017/myApp')

app.use('/uploads', serveGridfs(mongoConnection))
app.use('/uploads_byname', serveGridfs(mongoConnection, { byId: false }))

const options = {
  bucketName: 'somethingElse',
  setHeaders(res, path, stat) {
    if (stat && stat.contentType === 'application/pdf' && stat.length > 102400000) res.setHeader('Content-Disposition', 'attachment; filename = ' + path)
  }
}
app.use('/uploads2', serveGridfs(mongoConnection, { bucketName: 'somethingElse' }))

Retriving a file

# Assuming there is a file with an _id of 001 and a filename of cat.png in mongodb gridfs collection, the following commands will retrieve the same file

$ curl http://localhost:3000/uploads/001
$ curl http://localhost:3000/uploads_byname/cat.png

• Due to gridfs configuration, you can have an _id or filename containing slash, such as cat/001 or cat/tom.png as an _id and filename respectively. In this case, curl http://localhost:3000/uploads/cat/001 and curl http://localhost:3000/uploads_byname/cat/tom.png will resolve to the same file.