we are trying to validate the downloaded files with file size for the response which is incorrect and suggested to use content-md5 header, but we are not aware of it. let us know how to use this.
The suggestion could be related to this advisory which is advised to retrieve the checksum and file size from the following HTTP header fields returned in the file download response:
With regard to package delivery id, I understand that you download VBD files via /StandardExtractions/UserPackageDeliveries('<package delivery id')/$value endpoint. You can use curl with -I option to get only response's header. The MD5 checksum is in Content-MD5 header.
curl -I -Ls -H "Authorization: Token_xxx" -X GET "https://hosted.datascopeapi.reuters.com/RestApi/v1/StandardExtractions/UserPackageDeliveries%28%270x0634b9ef4aeb3026%27%29/%24value"
HTTP/1.1 200 OK Cache-Control: no-cache Pragma: no-cache Content-Length: 3471212 Content-Type: text/plain Content-Encoding: gzip Content-MD5: a6740f781a6289b145a59be91b0be6e3 Expires: -1 Accept-Ranges: bytes Server: Microsoft-IIS/7.5 Content-Disposition: attachment; filename=CBT-2018-06-06-NORMALIZEDMP-Report-1-of-1.csv.gz
Once the file is downloaded, you can run md5sum command in Linux to get md5 checksum for the downloaded file and then compare the output with value in the Content-MD5 header.
#md5sum CBT-2018-06-06-NORMALIZEDMP-Report-1-of-1.csv.gz #a6740f781a6289b145a59be91b0be6e3 CBT-2018-06-06-NORMALIZEDMP-Report-1-of-1.csv.gz
Hope this helps. If this is not what you are looking for, please elaborate.