HTTP file upload with node.js is changing the file - node.js

Question

I have a problem uploading an jpg file with node.js to my tomcat server - somewhere in the upload the file content is changed. I think, it is something with the encoding, but I hav no idea what I'm missing.
The node.js code is:
var agentOptions;
var agent;
agentOptions = {
host: 'this.is.my.server'
, port: '8443'
, path: '/'
, rejectUnauthorized: false
};
agent = new https.Agent(agentOptions);
var binaryFilename = "image.jpg";
var fContent = fs.readFileSync( binaryFilename );
console.log( "file size = " + fContent.length );
var boundary = '69b2c2b9c464731d'
var content = "--"+boundary+"\r\n"
+ "Content-Disposition: form-data; name=\"file\"; filename=\"image.jpg\"\r\n"
+ "Content-Type: application/octet-stream\r\n"
+ "Content-Transfer-Encoding: BINARY\r\n"
+ "\r\n"
+ fContent + "\r\n"
+ "--"+boundary+"--\r\n"
postOptions = {
headers: {
'Content-Type': 'multipart/form-data; boundary='+boundary ,
'Content-Length': Buffer.byteLength(content) ,
'Authorization': 'Basic ABCEDFE..'
} ,
host: 'this.is.my.server' ,
port: '8443' ,
path: '/restservices/uploadimage?data=value&data2=value2' ,
method: 'POST' ,
strictSSL: false ,
agent: agent
} ;
// Set up the request
post_req = https.request(
postOptions,
function(res) {
//
res.setEncoding('utf8') ;
res.on('data', function (chunk) {
console.log('Response: ' + chunk) ;
}) ;
}) ;
// post the data
post_req.write(content) ;
post_req.end() ;
Java code on the server starts with
#RequestMapping(value = "/uploadimage", method = RequestMethod.POST )
public #ResponseBody String uploadpreview(#RequestParam String data, #RequestParam String data1, #RequestParam("file") MultipartFile file) {
if (!file.isEmpty()) {
....
Start of the image before upload:
Start of the image after upload:
(source: dataplan.de)
Every byte with the highest bit set is converted to three bytes EF BF BD
I tried several things, maybe I'm missing something simple - at the moment I have no idea what I'm doing wrong.
Thanks for any ideas and tipps
Klaus

Answer 1

Here's another attempt:
const https = require('https');
const formData = require('form-data')();
var binaryFilename = process.argv[2] || 'image.jpg';
let request = https.request({
host: 'this.is.my.server'
port: '8443',
path: '/',
method: 'POST',
headers: formData.getHeaders()
}, (res) => {
res.on('data', (data) => {
console.log('Data received: ', data.toString());
});
});
request.on("error", (e) => {
console.error(e);
});
formData.append('image_file', require("fs").createReadStream(binaryFilename));
formData.pipe(request);