Question

I need to make a script that is server and client at the same time.

This needs to alternate from listening to trying to connect.

Is there a way to temporarily block any client from connecting while it proceeds to client mode and attempts to connect?

As far as I have noticed there is only a permanent way to stop this that would involve starting to listen again and I am trying to avoid that.

The idea is that this will run on multiple servers and it will have to connect to itself.

Each time a connection is made each party removes the other from list of (clients/destinations) once they exchange what they need to exchange.

So I need a way to block the listener while it attempts a connection cause on rare occasions two attempt connection to each other at the exact same time and bought hang waiting to be picked up but that does not happen.

Answer 1

You could either do:

• close() the listen socket (and maybe reopen it when needed)
• if the listen socket becomes readable, don’t call accept() yet (you can get away with this for a few seconds, but it does use OS resources)
• do call accept(), but immediately close() the resulting socket. (this is rather rude…)

The above three options are from the systemcall/OS level. I don’t know how PHP implements (or wraps) them.