async findMd5()

in source/ingest/lib/index.js [434:460]

• 20 lines of code
• 13 McCabe index (conditional complexity)

  async findMd5(data) {
    /* #1: x-amz-metadat-md5 is set, we are all good */
    if (((data || {}).Metadata || {}).md5) {
      return data.Metadata.md5;
    }

    /* #2: try object tagging */
    const src = (this.stateData.input || {}).src || this.stateData.event;
    const response = await CommonUtils.getTags(src.bucket, src.key).catch(() => undefined);
    const chksum = ((response || {}).TagSet || []).find(x =>
      x.Key === 'computed-md5');
    if (chksum && chksum.Value.match(/^([0-9a-fA-F]{32})$/)) {
      return chksum.Value;
    }

    /* #3: try ETag iff it is NOT multipart upload and SSE is disable or AES256 */
    if (!data.ServerSideEncryption
      || data.ServerSideEncryption.toLowerCase() === 'aes256') {
      /* the regex screens any multipart upload ETag */
      const matched = data.ETag.match(/^"([0-9a-fA-F]{32})"$/);
      if (matched) {
        return matched[1];
      }
    }

    return undefined;
  }