Rails download zip from binary data stream - ruby-on-rails

Question

I have a data-API to receive data from the file system. The data-API is a nodeJS server. Our webserver is a Rails server. From the webserver I send parameters to the API which files I want to download. The data-API then zips the request files and sends the zip back as binary data.
So far everything works fine. Now come the part where I'm stuck. I want to present the binary data as a download to the browser. I can either convert the binary data into a zip file and send that to the browser or have another clever solution that will present the binary data as a download.
Here's what I've got so far
Rails webserver side:
app/controllers/simulation_controller.rb
def download_multiple
files = JSON.parse(params[:files])
file_list = #simulation.sweep_points.find(params[:sweep_point_id]).file_list
send_data file_list.zip(files: files), filename: 'archive.zip', type: 'application/zip', disposition: 'attachment'
end
app/models/file_list.rb
def zip
uuid = SecureRandom.uuid
simulation = sweep_point.simulation
files = files[:files].join(" ")
url = URI.parse("http://localhost:3003/files/zip/#{simulation.name}/#{uuid}");
req = Net::HTTP::Get.new(url.to_s)
req.add_field("files", files)
res = Net::HTTP.start(url.host, url.port) { |http| http.request(req) }
content = res.body
content.force_encoding("ASCII-8BIT")
end
nodeJS data-API side:
exports.zip_simulation_files = (req, res) => {
const { headers, method, url } = req;
var simulation = req.params.simulation;
var uuid = req.params.uuid;
var files, command;
req.on("error", (err) => {
console.error(err);
});
files = req.headers.files;
command = "cd postprocess/bumblebee-zip " + "run" + simulation + " " + uuid + " " + "'" + files + "'";
execute(command, (data) => {
res.on("error", (err) => {
console.error(err);
});
const zipFilePath = "/home/samuel/test_bumblebee/.zips/run" + simulation + "-files-" + uuid + ".zip"
var zipFile = fs.readFileSync(zipFilePath);
var stats = fs.statSync(zipFilePath);
res.writeHead(200, {
'Content-Type': 'application/zip',
'Content-Disposition': 'attachment; filename="archive.zip"',
'Content-Length': stats.size,
'Content-Transfer-Encoding': 'binary'
});
res.end(zipFile, 'binary');
});
}
So far I'm getting back a response that is a string which seems to be a binary string. Which starts and end with this:
"PK\x03\x04\x14\x00\x00\x00\b\x00\xA8\x89\xDBJ\xB1\xB8\xA1\xBF2\x03\x00\x00\xB7F\x00\x006\x00\x1C\x00runZhangD3FINAL/13.0V/annihilation_abs_profile_001.outUT\t\x00\x0 ....... x06\x00\x00\x00\x00\x05\x00\x05\x00l\x02\x00\x00)\x10\x00\x00\x00\x00"
I've looked into different solutions in trying to turn the binary data string into a zip file or presenting the stream directly to the browser but nothing worked. Either the zip is not created or the binary was not seen as proper data.
What would be a good solution?