In Yùn, how can I write a server side script which talks with a 32U4 sketch?

My question is doublefold:
(a) how to configure uhttp to start a server side script (SSS)?
(b) how to send something from SSS to the LININO side of the Bridge for final deliver to the sketch?
As for the (a) part of the question: I have some experience in writing and setting to work PHP scripts under Apache, but here we have uhttpd, which seems to have a different configuration philosophy; moreover I would prefer a solution similar to the REST as already implemented, but I need to do some processing before going to the skecth… I googled for a couple of days with no luck… and I could not understand the mechanism by which (apparently) a certain frontend is called for any URL starting with http://<arduino_node>/arduino … (apparently uhttpd does not support Rewrite rules, that could make this possible).
(b) On a book I found a pictures implying that the communication between uhttpd and 32U4 passes trough LuCI and then via sockets TCP 5555 and TCP 5700. I suspect this is not correct; perhaps more knowledge about the existing architecture would help me, but I have not been able to find documentation, or to understand which kilograms of the existings tons of code to examine…

Hi, there! ...more than 450 views and no reply. Please, in case I have made some mistake, just tell me and I will try to correct; but please, please, do not let me alone.. :roll_eyes:

There is a separate section for the Yún. You may have better results if you post this query there.

Many thanks! I don't know how happened this to have slipped my eyes... I will repost the question there; I hope that in this case a repost will be forgiven..