Servers don't make requests. Clients do. Servers respond to requests.
This is a server in a sense that it is a server that I already have. It will serve the arduino data to other clients.
In the protocoll it is maybe a client but that is a irrelevant detail in regard to my questions.
All the libraries are available. What you need to do, if the Arduino is to be a server, is parse the GET request, and serve up the requested page, calling other library functions, as needed, to get the data required to service the request.
Yes I already know that libraries exist that can act as a webserver ( Instead of you I even posted a URL).
What I've asked for is if there is a webserver that implements the core arduino functions.
In not answering this question I have to assume that you don't know or such a thing does not exist.
In general, the WebServer library is overkill, since the Arduino is already serving some purpose for which you want the data to be available from the internet. Possibly, you want to control some stuff from the internet, too.
Get more specific about the Arduino you have, what is connected to it, what you want to expose to the world, and what you want the client to be able to do, if you need help doing something.
No, I did not mention the Internet. I want a library that can call the core arduino functions (digitalRead, digitalWrite, etc) by LAN.
At the moment I have an old computer with a python program that controls my heating with the parallel PC Interface.
This computer is defective because of dirt and heat in the heating room. I therefore want to replace this computer with an arduino acting as low level interface to the heating and the seperated server which controls the arduino by LAN.
I don't want to reimplement this software for the arduino. Instead this program should run on the server and only the parallel interface part should be replaced by the LAN protocoll to the arduino.