Amazon MWS SubmitFeed Content-MD5 HTTP header did not match the Content-MD5 calculated by Amazon

Question

I know this question is not new but all the solution I get for this are in PHP or my issue is different from them.

I am using MWS feed API to submit flat file for Pr

Answer 1

Amazon requires the md5 hash of the file in base64 encoding.

Your code:

var fileReadStream = fs.createReadStream('/path/to/file.txt');
var file = fileReadStream.toString('base64'); //'[object Object]'
var contentMD5Value = crypto.createHash('md5').update(file).digest('base64');

wrongly assumes that a readStream's toString() will produce the file contents, when, in fact, this method is inherited from Object and produces the string '[object Object]'.

Base64-encoding that string always produces the 'FEGnkJwIfbvnzlmIG534uQ==' that you mentioned.

If you want to properly read and encode the hash, you can do the following:

var fileContents = fs.readFileSync('/path/to/file.txt'); // produces a byte Buffer
var contentMD5Value = crypto.createHash('md5').update(fileContents).digest('base64'); // properly encoded

which provides results equivalent to the following PHP snippet:

$contentMD5Value = base64_encode(md5_file('/path/to/file.txt', true));