Multer with S3

index.mjs

import express from 'express'
import compression from 'compression'
import multer from 'multer'

import upload from './upload.mjs'
const uploadFile = upload.single('uploadedfile')

const app = express()

app.use(compression())
app.use(express.static('./dist'))

app.post('/upload', (req, res) => {
  uploadFile(req, res, err => {
    if (err) {
      return res.status(500).send(err)
    } else {
      const ending = req.file.key.replace(/\.[^/.]+$/, "")
      return res.send(`https://gpsmeasure.com/map/${ending}`)
    }
  })
})

app.get('/*', (req, res) =>
  res.sendFile('index.html', {
    root: process.cwd() + '/dist'
  })
)

app.listen(3333, '0.0.0.0', () => {
  console.log(`Listening on https://0.0.0.0:3333`)
})

upload.mjs

import multer from 'multer'
import multerS3 from 'multer-s3'
import generate from 'nanoid/generate'
import AWS from 'aws-sdk'

/**
 * AWS Config
 */
const s3 = new AWS.S3({
  accessKeyId: process.env.ACCESS_KEY_ID,
  secretAccessKey: process.env.SECRET_ACCESS_KEY
})

/**
 * Key (path and filename) for object in bucket
 */
const key = (req, file, cb) => {
  const date = new Date().toISOString().replace('-', '/').split('T')[0].replace('-', '/')
  const id = generate('1234567890qwertyuiopasdfghjklzxcvbnm', 32)
  const path = `${date}/${id}.kml`

  cb(null, path)
}

/**
 * Multer Storage config
 */
const storage = multerS3({
  s3,
  bucket: 'kml.gpsmeasure.com',
  key
})

/**
 * File limits
 */
const limits = {
  fieldNameSize: 100,
  fieldSize: 1024,
  fields: 0,
  fileSize: 5 * 1024 * 1024,
  files: 1,
  parts: 100,
  headerPairs: 2000
}

/**
 * The function should call `cb` with a boolean
 * to indicate if the file should be accepted
 * 
 * @param req 
 * @param file 
 * @param cb
 */
const fileFilter = (req, file, cb) => {
  // Check MIME
  if (!(file.mimetype && file.mimetype === 'application/vnd.google-earth.kml+xml'))
    return cb(new Error('File is not "application/vnd.google-earth.kml+xml" type.'))

  // Everything is OK
  cb(null, true)

  // // To reject this file pass `false`, like so:
  // cb(null, false)
}
 
const upload = multer({
  storage,
  limits,
  fileFilter
})

export default upload