How to organize a data transfer environment for an XML-based protocol?

Question

Apache HTTP Server

Please point me in the right direction. It is necessary to raise an XML-based protocol between two machines via the tcp / udp interface (in this context, this is an interface).

The next question is: how to organize the data transmission medium itself?

The server has a white ip, the client has a gray ip.

All that came to my mind was to put apache on the server and send data to the script using the POST method, and receive them using the GET method.

But I don't really like this concept, maybe. is it possible to do it differently? On sockets?

Another problem is this: the server cannot send data to the client, only the client can receive it. (grey ip for clients)

Answer 1

HTTPS CONNECT + functionality of constant connection support from the client side (reconnection on break).
Inside this TLS connection, you can implement any exchange: even an HTTP-style request-response, even just data exchange.
Advantage - transparent passage of proxy servers + encryption.
Some proxies cut HTTPS CONNECT if it lasts more than a day, so the client software must be able to recreate it.

Answer 2

Nginx + application in the language closest to you (js, perl, PHP, Ruby, ...)