Do-it-yourself Layer7 filtering on the server?

Question

DDoS Protection

It is clear that good hosts provide L3-L4 DDoS protection by default. They have hefty channels and already developed measures to counter DDoS attacks. An example of such a host is OVH.
How to filter Layer7 traffic on your own on dedicated servers? For example, analyze packets with some scripts and if something is blocked. Or if there are many calls to the server, then block.
You need to protect the game server (not minecraft and not cs), but your own game.
And just wondering how it's done. All DDoS defenders talk about some kind of Layer7 rules, according to which they block spurious traffic.
I didn't find anything on the Internet.

Answer 1

Depends on the application. Usually limit the number of requests per period of time for certain URIs.
For example, by means of the application itself, Laravel throttle can do this.

Answer 2

just cut off the left in the game, there are no other options to protect the game on the seventh level, since this is your protocol
, you can write a proxy for this,
if http is cut in nginx or in iptables through the module