MultiPart Handler

multipart.js

'use strict'

const config = require('../../config')
const { MultipartError } = require('./errors')
const fs = require('fs')
const path = require('path')
const nanoid = require('nanoid')

const Multipart = (request, response, done) => {
  // Note: onFile and addToBody cannot be handled on a per reuqest basis at the moment
  // https://github.com/fastify/fastify-multipart/issues/129
  // https://github.com/fastify/fastify-multipart/issues/131#issuecomment-649345687
  if (!request.isMultipart()) {
    return response.code(400).header('Connection', 'close').send(new MultipartError('Request is not multipart'))
  }

  const fields = {}
  const files = {}
  const mp = request.multipart(() => { }, () => { }, {
    limits: {
      fileSize: 1024 * 1024 * 8,
      files: 10 },
    allowed: ['image/jpeg', 'image/jpg', 'image/png', 'image/gif', 'image/webp', 'video/mp4', 'video/webm', 'text/html'],
  })

  mp.on('field', (fieldname, value) => {
    fields[fieldname] = value
  })

  mp.on('file', (fieldname, file, filename, encoding, mimetype) => {
    if (!filename || filename == '') {
      file.destroy(new Error('No file provided'))
    } else if (!mp.opts.allowed.includes(mimetype)) {
      file.destroy(new Error('Not allowed file type'))
    } else {
      // Generate new filename
      filename = nanoid.customAlphabet('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz', 11)() + path.extname(filename)

      // Add file to local list
      files[fieldname] = files[fieldname] || []
      files[fieldname].push({
        filename: filename,
        mimetype: mimetype,
        extension: path.extname(filename).substring(1),
      })
      // Write stream to local file
      let destination = path.join(config.storage.temp, filename)
      var ffs = fs.createWriteStream(destination)
      file.pipe(ffs)
    }

    file.on('limit', () => {
      file.destroy(new Error('File size limit reached'))
    })

    file.on('error', (error) => {
      mp.destroy(error)
    })
  })

  mp.on('partsLimit', () => {
    mp.destroy(new Error('Maximum number of form parts reached'))
  })

  mp.on('filesLimit', () => {
    mp.destroy(new Error('Maximum number of files reached'))
  })

  mp.on('fieldsLimit', () => {
    mp.destroy(new Error('Maximim number of fields reached'))
  })

  mp.on('error', (error) => {
    for (let i in files) {
      for (let j in files[i]) {
        let source = path.join(config.storage.temp, files[i][j].filename)
        if (fs.statSync(source)) {
          fs.unlinkSync(source)
        }
      }
    }
    /// TODO: Test - but do not THROW the error here, or Node.js will crash.
    const appError = new MultipartError('Error in multipart file upload handler; lib/multipart', error)
    return response.code(400).header('Connection', 'close').send(appError)
  })

  mp.on('finish', () => {
    request.body = { ...fields, ...files }
    done()
  })
}

module.exports = {
  Multipart,
}