File download giving corrupt file in Nodejs - node.js

Question

I am using request module in NodeJS to read data from AWS S3. When I am downloading the file(docx or image or pdf) using below code,its giving me an invalid/corrupted file. But when I am downloading .txt file it's not getting corrupted and I am able to see file in notepad.
I did a bit of googling and as suggested also tried by setting encoding to binary, still its not giving required result.
File upload is working fine. And I am able to see the uploaded file in AWS console.
File download code
var s3 = new properties.AWS.S3();
var params = {Bucket: properties.AWS_BUCKET, Key: req.headers['x-org'] + "/" + "talk" + "/" + req.body.fileName};
s3.getSignedUrl('getObject', params, function (err, URL) {
if (err) {
console.log("Error inside the S3");
console.log(err, err.stack); // an error occurred
res.send(null);
} else {
console.log("After getObject:-" + URL);
request({
url: URL, //URL to hit
method: 'GET',
encoding: 'binary'
}, function (error, response, body) {
if (error) {
console.log(error);
} else {
//console.log(response.statusCode, body);
res.set('content-disposition', 'attachment; filename=' + req.body.fileName);
res.send(body);
}
});
}
});
Update:-
I have narrow down the error, and just trying to send the file by reading file from local file system. Even that also is giving the corrupted files on client.
Here's the code for same
var filePath = path.join(__dirname, '..', '..', '..', 'downloads', req.body.fileURL);
var stat = fs.statSync(filePath);
var filename = path.basename(filePath);
var mimetype = mime.lookup(filePath);
console.log("mimetype=" + mimetype);
res.setHeader('Content-disposition', 'attachment; filename=' + filename);
res.setHeader('Content-type', mimetype + ";charset=UTF-8");
res.setHeader('Content-Length', stat.size);
var filestream = fs.createReadStream(filePath);
filestream.pipe(res);

Answer 1

Finally able to solve the problem.
Got solution hint from this blog https://templth.wordpress.com/2014/11/21/handle-downloads-with-angular/.
Per this blog
When testing with binary content like zip files or images, we see
that the downloaded content is corrupted. This is due to the fact that
Angular automatically applies transformation on the received data.
When handling binary contents, we want to get them as array buffer.
Final working code is:-
var filePath = path.join(__dirname, '..', '..', '..', 'downloads', req.body.fileURL);
var file = fs.createWriteStream(filePath);
s3.getObject(params).
on('httpData', function(chunk) {
//console.log("inside httpData");
file.write(chunk);
}).
on('httpDone', function() {
console.log("inside httpDone");
file.end();
//file.pipe(res);
}).
send(function() {
console.log("inside send");
res.setHeader('Content-disposition', 'attachment; filename=' + filePath);
res.setHeader('Content-type', mimetype);
res.setHeader('Transfer-Encoding', 'chunked');
var filestream = fs.createReadStream(filePath);
filestream.pipe(res);
});