How to pass a file through the server without uploading to the server?

Question

PHP

There is a PHP7 + Nginx server. You need to send the file to another domain, for this now the JS file is sent to the server on a POST request, and then sent to another domain.
Is it possible to redirect the request to another domain without uploading a file to the server, reducing the load on the server?
p/s Perhaps there are other solutions, I will be glad for a hint :)
UPDATE: the server is not under control and the solution is essentially bypassing Access-Control-Allow-Origin. I also came across this "proxy" method https://github.com/Rob--W/cors-anywhere/#documentation
Is it possible to implement this on Nginx and send POST requests with a file (multipart/form-data) in this way? ?

Answer 1

Without saving the file, you can send it to another server by proxying the request through nginx.
In theory, it will be enough to add a location block with proxy_pass to the desired address.
If you are accessing the second server by hostname, then you should also add resolver , I usually put Google's 8.8.8.8

Answer 2

You can, just like you are uploading to your server now, directly upload to the destination server via ajax.