node.js - 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 Price and Quantity Updates and always get the following error:

the Content-MD5 HTTP header you passed for your feed did not match the Content-MD5 we calculated for your feed

---

I would like to ask 3 questions here:-

1. ContentMD5Value parameter is optional as given in doc, but if i not passed that than it will say that you must enter ContentMD5Value.

2. As in doc the ContentFeed which we are given to Amazon. Amazon create contentMD5 for that file and then compares that contentMD5 value with the contentMD5 value we send to Amazon.
   If both match then OK, otherwise it will throw an error. But if suppose I will not send the file then also the same errors come that MD5 does not match. How is that possible? Which file are they calculating the MD5 for? Because I haven't send the file in ContentFeed.

3. If I send the contentMD5 in a header as well as parameter and sending the ContentFeed in body, I still get the error.

Note:- I am sending the contentMD5 in a header as well as in a parameters in form using request module and also calculating the signature with that and then pass the contentFeed in body.

I am using JavaScript (Meteor), I calculate the md5 using the crpyto module.
First, I think that my md5 is wrong but then I tried with an online website that will give me the md5 for a file the md5.

for my file is:

MD5 value: d90e9cfde58aeba7ea7385b6d77a1f1e
Base64Encodevalue: ZDkwZTljZmRlNThhZWJhN2VhNzM4NWI2ZDc3YTFmMWU=

The flat file I downloaded from for Price and Quantity Updates:-

https://sellercentral.amazon.in/gp/help/13461?ie=UTF8&Version=1&entries=0&

I calculated the signature also by giving ContentMD5Value while calculating the signature.

FeedType:'_POST_FLAT_FILE_PRICEANDQUANTITYONLY_UPDATE_DATA_'

As, I read documentation for that I passed the MD5-header in headers and also send as parameter.

Amazon doc says:

Previously, Amazon MWS accepted the MD5 hash as a Content-MD5 header instead of a parameter. Passing it as a parameter ensures that the MD5 value is part of the method signature, which prevents anyone on the network from tampering with the feed content.

Amazon MWS will still accept a Content-MD5 header whether or not a ContentMD5Value parameter is included. If both a header and parameter are used, and they do not match, you will receive an InvalidParameterValue error.

I am using the request module for http requests.

I am passing all the required keys, seller id, etc. in form of request module and passing the FeedContent in body.

I tried sending the file as follows:

Method for submitFeed is:-

submitFeed : function(){
    console.log("submitFeedAPI running..");
    app  = mwsReport({auth: {sellerId:'A4TUFSCXD64V3', accessKeyId:'AKIAJBU3FTBCJUIZWF', secretKey:'Eug7ZbaLljtrnGKGFT/DTH23HJ' }, marketplace: 'IN'});
    app.submitFeedsAPI({FeedType:'_POST_FLAT_FILE_PRICEANDQUANTITYONLY_UPDATE_DATA_'},Meteor.bindEnvironment(function(err,response){
        if(err){
            console.log("error in submit feed...")
            console.log(err)
        }
        else{
            console.log("suuccess submit feed....")
            console.log(response);
        }
    }))

Method that call Amazon submitFeedAPI is:-

    var submitFeedsAPI =  function(options, callback){
        console.log("submitFeedsAPI running...");
    var fileReadStream = fs.createReadStream('/home/parveen/Downloads/test/testting.txt');
        var contentMD5Value = crypto.createHash('md5').update(file).digest('base64');

    var reqForm = {query: {"Action": "SubmitFeed", "MarketplaceId": mpList[mpCur].id, "FeedType":options.FeedType,"PurgeAndReplace":false,"ContentMD5Value":contentMD5Value}}; 
            mwsReqProcessor(reqForm, 'submitFeedsAPI', "submitFeedsAPIResponse", "submitFeedsAPIResult", "mwsprod-0000",false,file, callback);
    }


also try

    var fileReadStream = fs.createReadStream('/home/parveen/Downloads/test/testting.txt');
    var base64Contents = fileReadStream.toString('base64');
    var contentMD5Value = crypto.createHash('md5').update(base64Contents).digest('base64');

mwsReqProcessor function is as below:-

 mwsReqProcessor = function mwsReqProcessor(reqForm, name, responseKey, resultKey, errorCode,reportFlag,file, callback) {

        reqOpt = {
            url: mwsReqUrl,
            method: 'POST',
            timeout: 40000,
            body:{FeedContent: fs.readFileSync('/home/parveen/feedContentFile/Flat.File.PriceInventory.in.txt')},
            json:true,
            form: null,
            headers: {
                // 'Transfer-Encoding': 'chunked',
                //'Content-Type': 'text/xml',
               // 'Content-MD5':'ZDkwZTljZmRlNThhZWJhN2VhNzM4NWI2ZDc3YTFmMWU=',
                // 'Content-Type': 'text/xml; charset=iso-8859-1'
                'Content-Type':'text/tab-separated-values;charset=UTF-8'
            },
        }
        reqOpt.form = mwsReqQryGen(reqForm);
        var r = request(reqOpt, function (err, res, body){
            console.log(err)
            console.log(res)
        })
        // var form  = r.form();
        //form.append('FeedContent',fs.createReadStream('/home/parveen/feedContent//File/Flat.File.PriceInventory.in.txt'))
    }

Method for mwsReqQryGen generation:-

mwsReqQryGen = function mwsReqQryGen(options) {
    var method     = (options && options.method) ? ('' + options.method) : 'POST',
        host       = (options && options.host)   ? ('' + options.host)   : mwsReqHost,
        path       = (options && options.path)   ? ('' + options.path)   : mwsReqPath,
        query      = (options && options.query)  ? options.query         : null,


        returnData = {
          "AWSAccessKeyId": authInfo.accessKeyId,
          "SellerId": authInfo.sellerId,
          "SignatureMethod": "HmacSHA256",
          "SignatureVersion": "2",
          "Timestamp": new Date().toISOString(),
           "Version":"2009-01-01",
        },
        key;

    if(query && typeof query === "object")
      for(key in query)
        if(query.hasOwnProperty(key)) returnData[key] = ('' + query[key]);

    if(authInfo.secretKey && method && host && path) {

      // Sort query parameters
      var keys = [],
          qry  = {};

      for(key in returnData)
        if(returnData.hasOwnProperty(key)) keys.push(key);

      keys = keys.sort();
      for(key in keys)
        if(keys.hasOwnProperty(key)) qry[keys[key]] = returnData[keys[key]];
      var sign = [method, host, path, qs.stringify(qry)].join("
");
      console.log("..................................................")
      returnData.Signature = mwsReqSignGen(sign);

    }
//console.log(returnData); // for debug

return returnData;

};

I also tried with following:-

reqOpt = {
    url: mwsReqUrl,
    method: 'POST',
    timeout: 40000,
    json:true,
    form: null,
    body:  {FeedContent: fs.createReadStream('/home/parveen/feedContentFile/Flat.File.PriceInventory.in.txt')},
    headers: {
        // 'Transfer-Encoding': 'chunked',
        //'Content-Type': 'text/xml',
       // 'Content-MD5':'ZDkwZTljZmRlNThhZWJhN2VhNzM4NWI2ZDc3YTFmMWU=',
        //   'Content-Type': 'text/xml; charset=iso-8859-1'
    },
}

I also tried without JSON and directly send the file read stream in the body, i.e:

reqOpt = {
    url: mwsReqUrl,
    method: 'POST',
    timeout: 40000,
    form: null,
    body:  fs.createReadStream('/home/parveen/feedContentFile/Flat.File.PriceInventory.in.txt'),
    headers: {
        // 'Transfer-Encoding': 'chunked',
        //'Content-Type': 'text/xml',
     //   'Content-MD5':'ZDkwZTljZmRlNThhZWJhN2VhNzM4NWI2ZDc3YTFmMWU=',
        //   'Content-Type': 'text/xml; charset=iso-8859-1'
    },
}

But same error comes every time:

the Content-MD5 HTTP header you passed for your feed did not match the Content-MD5 we calculated for your feed

I want to know where I am doing wrong or what is the right way to submit feed API and sending the file using request module.

I also tried with the code given on MWS to generate the MD5 but same error occurred each time.

My .txt file as follows:

sku price   quantity
TP-T2-00-M      2

Any help is much appreciated

Answer 1

finally i got the solution as Ravi said above. Actually there are few points i want to clear here for you all who are facing the same issue:-

1. Amazon marketplace API doc is not giving proper information and example. Even i guess the documentation is not updated . As in doc they said that ContentMD5Value parameter value is optional on this page

   You can check there they clearly mention that the field is not required but if you not pass than they gives the error that you must pass content MD5 value.

   So that is wrong. ContentMD5 is required attribute.

2. They said in the same doc that you need to send file data weather its a xml or flat-file in the field key name i.e. FeedContent.

   But that is also not needed you can send the file with any name no need to give FeedContent key for the file you just need to send the file in stream.

3. They will give the same error of contentMD5 not match weather you send file or not because if they not found file than the contentMD5 you send will not match to that. SO if you are getting the ContentMD5 not match error than check the following:-

   1. Check that you are generating the right MD5 code for your file you can check whether you are generating the right code or not by there java code they given on doc . You can get that from this link

   2. Don't trust on online websites for generating the MD5 hash and base64 encoding.

   3. If your MD5 is matched with the MD5 generated from Java code they given than one thing is clear that your MD5 is right so no need to change on that.

   4. Once your MD5 is correct and after that also if you get the same error that is:-

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

ContentMD5 not matched .Than you need to check only and only you file uploading mechanism. Because now the file you are sending to Amazon is not either correct or you are not sending it in the right way.

Check for file upload

For checking whether or not you are sending the right file you need to check with following:-

1. You need to send the required parameters like sellerId, marketplaceId, AWSAccessKey etc. as query params.

2. You need to send the file in the form-data as multipart , if you are using the request module of node.js than you can see the above code given by Ravi.

3. you need to set the header as only:-

   'Content-Type': 'application/x-www-form-urlencoded'

No need to send the header as chunked or tab separated etc because i don't need them any more they are even confuse me because somewhere someone write use this header on other place someone write use this header. So finally as i am abel to submit this API i didn't need any of the header rather than application/x-www-form-urlencoded.

Example:-

reqOpt = {
   url: mwsReqUrl,
   method: 'POST',
   formData: {
      my_file: fs.createReadStream('file.txt')
  },
  headers: {
     'Content-Type': 'application/x-www-form-urlencoded'
  },
qs: { }// all the parameters that you are using while creating signature.

Code for creating the contentMD5 is:-

var  fileData= fs.readFileSync('/home/parveen/Downloads/test/feed.txt','utf8');

var contentMD5Value = crypto.createHash('md5').update(fileData).digest('base64');

As i am facing the issue that is because i am using form and form-data simultaneously via request module so i convert my form data with qs(query string) and file in form-data as multipart.

So in this way you can successfully submit the API for submit feed.