@uppy/companion/src/server/helpers/upload.js

OAuth helper and remote fetcher for Uppy's (https://uppy.io) extensible file upload widget with support for drag&drop, resumable uploads, previews, restrictions, file processing/encoding, remote providers like Dropbox and Google Drive, S3 and more :dog:

import logger from '../logger.js'
import Uploader from '../Uploader.js'

export async function startDownUpload({ req, res, getSize, download }) {
  logger.debug('Starting download stream.', null, req.id)
  const { stream, size: maybeSize } = await download()

  let size
  // if we already know the size from the GET response content-length header, we can use that
  if (
    typeof maybeSize === 'number' &&
    !Number.isNaN(maybeSize) &&
    maybeSize > 0
  ) {
    size = maybeSize
  }
  // if not, we may need to explicitly get the size
  // note that getSize might also return undefined/null, which is usually fine, it just means that
  // the size is unknown and we cannot send the size to the Uploader
  if (size == null && getSize != null) {
    size = await getSize()
  }
  const { clientSocketConnectTimeout } = req.companion.options

  logger.debug('Instantiating uploader.', null, req.id)
  const uploader = new Uploader(Uploader.reqToOptions(req, size))

  // "Forking" off the upload operation to background, so we can return the http request:
  ;(async () => {
    // wait till the client has connected to the socket, before starting
    // the download, so that the client can receive all download/upload progress.
    logger.debug(
      'Waiting for socket connection before beginning remote download/upload.',
      null,
      req.id,
    )
    await uploader.awaitReady(clientSocketConnectTimeout)
    logger.debug(
      'Socket connection received. Starting remote download/upload.',
      null,
      req.id,
    )

    await uploader.tryUploadStream(stream, req)
  })().catch((err) => logger.error(err))

  // Respond the request
  // NOTE: the Uploader will continue running after the http request is responded
  res.status(200).json({ token: uploader.token })
}