How to download .xlsx file from AWS MWS API json response?

Finally, I got a solution. I changed my method to call API as below and I got a proper excel file.

I used node-fetch and then send request to Amazon MWS by node-fetch.

node-fetch decode content encoding (gzip/deflate) properly and convert string output to UTF-8 automatically.

var param = {};  param['AWSAccessKeyId']   =  'xxxxxxxxxxxxx';   param['Action']           = 'GetReport';  param['MarketplaceId']    =  'xxxxxxxxxxxxx';   param['SellerId']         =  'xxxxxxxxxxxxx';   param['ReportId']         =  'xxxxxxxxxxxxx';   param['ItemCondition']    = 'New';   param['SignatureMethod']  = 'HmacSHA256';    param['SignatureVersion'] = '2';   param['Timestamp']        = encodeURIComponent(new Date().toISOString());  param['Version']          = '2009-01-01';   secret = 'xxxxxxxxxxxxx';   var url = [];  for(var i in param){    url.push(i+"="+param[i])  }  url.sort();  var arr = url.join("&");    var sign  = 'POST\n'+'mws.amazonservices.com\n'+'/Reports/2009-01-01\n'+arr;  const crypto = require('crypto');  let s64 = crypto.createHmac("sha256", secret).update(sign).digest('base64');  let signature = encodeURIComponent(s64);  var bodyData = arr+"&Signature="+signature;  const fileName = "sheetjs.xlsx";  var apiResponse = await fetch('https://mws.amazonservices.com/Reports/2009-01-01', {    method: 'POST',    body: bodyData,    headers: {      'content-type': 'application/x-www-form-urlencoded',       'Accept': '',    },  })  .then(res => {    const dest = fs.createWriteStream('./'+fileName);    res.body.pipe(dest).on('finish', function(){      //console.log('done');      return {'Status': 200, 'Message': 'Downloaded'};    });      })  .catch(error => {     console.log('Request failed', error);  });      return apiResponse;}