[Feature Request] Extending the Network Control Interface to allow loading games

[Gikkman]

I've been looking at the Network Control Interface (NCI), and I feel I got some cool ideas for what one could do by allowing external programs control a running instance of RetroArch. I've tinkered with similar capabilities in other emulators, but those are often single-system emulators. Bringing such capabilities to RetroArch would be very powerful I think.

The current API of the NCI can be found here:
https://docs.libretro.com/development/retroarch/network-control-interface/

One of the more central parts that's missing though would be the ability to tell the emulator to load a certain game, preferably by passing it an absolute path. From my understanding of the code, the current NCI works by simulating activating pressing certain hotkeys, such as RARCH_FAST_FORWARD_KEY or RARCH_LOAD_STATE_KEY. I recon my feature request would probably require some kind of re-architecture of how this works, or at least extend the capabilities of it. I don't understand enough of how the feature work to suggest an approach though.

There are several more things I could suggest for extending the NCI, but if this feature is put in place, it would allow for starting to tinker with some external tools.

[LibretroAdmin]

@cthulhu-throwaway what do you make of this?

[RandomDude560]

I'd also like to load games this way, so I had a look at this.

commands are defined here

RetroArch/command.h

Line 427 in f121847

static const struct cmd_action_map action_map[] = {

network commands seem to originate here in command_network_poll

RetroArch/command.c

Line 205 in f121847

static void command_network_poll(command_t *handle)

parsing is done here, this seems to support arguments already and uses action_map if one was provided otherwise it uses map

RetroArch/command.c

Line 160 in f121847

static void command_parse_msg(

there are commands with arguments e.g. SET_SHADER

RetroArch/command.h

Line 429 in f121847

{ "SET_SHADER", command_set_shader, "<shader path>" },

RetroArch/command.c

Line 1702 in f121847

bool command_set_shader(command_t *cmd, const char *arg)

can we use SET_SHADER from the network interface? how are arguments provided? 'SET_SHADER "path/to/someshader"'?
if so it should be possible to make a command_load_content method which invokes the same code path the GUI uses?

I tried 'LOAD_STATE_SLOT 0' for simplicity but with no success, LOAD_STATE worked though.

If everything works sending something like 'LOAD_CONTENT "/path/to/game.bin"' should do the same as selecting something with load content in the GUI.
Another "LOAD_CORE" command would be needed for standalone cores.
Path arguments should be UTF-8 to support unicode, no idea if command_parse_msg already does this.
This should also extend stdin and uds interfaces as they use this code as well.