Oversimplifying my use case, imagine a Perl program running on a headless Linux computer. A simple Jukebox playing random tracks from a play list, managed by parameters, endlessly running. Occasionally it also periodically plays announcements, such as song metadata, commercials, weather, etc between tracks.

I want to be able to send simple HTTP commands to the headless server to, for example, change playlists, advance to next, repeat current, reshuffle, or manage the frequency of announcements, etc.

These commands from a web browser (wget, curl, etc) via cell phone, computer, etc would take the form of http://host:port/CMD=XXXX. Where XXXX might be ATPN = play-next, ATRC = repeat-current; ATLP3 = load playlist #3; ATPP = pause playback; ATRP = resume playback, ATATF60 = adjust time announcement frequency to 60 minutes, etc. These command generally just modify variable in the host.

I do this often on Arduino/NodeMCU’s using the ESP8266WiFi.h library. In setup() I initialize the server. In loop() I simply check, validate, process, and reply to any client request each iteration.