proxy_from_s3.js

/* Fetch a file from s3 as a Stream
 *
 * @param fileId the fileId to fetch
 * @return {stream: Stream, meta, contentType, contentLength}
 */
export async function fetchStream({ fileId }) {
  try {
    const key = makeS3Key(fileId);
    const fileOpts = { Bucket: BUCKET, Key: key };
    const { stream, data } = await Promise.props({
      stream: S3.getObject(fileOpts).createReadStream(),
      data: fetchMeta({ fileId }),
    });

    const contentLength = data.ContentLength;
    return { stream, meta: data.meta, contentType: data.contentType, contentLength };
  } catch (err) {
    if (err.name === 'NoSuchKey') {
      throw Boom.notFound(`File not found ${fileId}`);
    }

    throw err;
  }
}