Node.js Request pass response of api call as get response

Question

I'm new to node.js. I'm trying to build a GET Method which is calling an external API. The response which is an octet-stream should be passed through as response. Unfortunately I get a file download but the files are not readable.

app.get('/askForFile/:id',(req, res) => {
requestOptions2.url = apiOptions.server + '/externalFileAPI/Download?id=' + req.params.id

request(requestOptions2, (err, response, body) => {
    if (err) {
      console.log(err);
    } else if (response.statusCode === 200) {
        res.header('content-type', response.headers['content-type'])
        res.header('content-disposition', response.headers['content-disposition'])  
        res.header('content-length', response.headers['content-length']) 
        res.send(body)
    } else {
      console.log(response.statusCode);
    }
  });  

})

I wasted lot of hours to solve this problem. Would be great if someone could help me. Thanks in advance.

Best regards Mini25