pollnet

Compact polling-based C-API networking library designed to be easily used from within game-embedded LuaJIT environments (e.g., mods)

Features

Websocket client and server (both ws:// and wss:// for clients)
TCP client and server
bare-bones HTTP client: simple GET/POST
bare-bones HTTP server: serve static files from disk or from memory

Usage (luajit FFI bindings)

-- pollnet.lua FFI loads pollnet.dll
local pollnet = require("pollnet") 

local sock = pollnet.open_ws("wss://irc-ws.chat.twitch.tv:443")
-- special nick for anon read-only access on twitch
sock:send("NICK justinfan" .. math.random(1, 100000))
sock:send("JOIN #some_twitch_channel")

-- assuming that you can run a callback each frame or on a timer
each_game_tick(function()
  if not sock then return end
  local happy, msg = sock:poll()
  if not happy then
    sock:close() -- good form to avoid keeping sockets open
    sock = nil
    return
  end
  if msg == "PING :tmi.twitch.tv" then
    sock:send("PONG :tmi.twitch.tv")
  elseif msg then
    print("CHAT: " .. msg) 
  end
end)

-- HTTP requests work roughly the same way, except you
-- only get three messages back: status code, headers, and body
local req_sock = pollnet.http_get("https://www.example.com")
local part_order = {"STATUS CODE:", "HEADERS:", "BODY:"}
local parts = {}
each_game_tick(function()
  if not req_sock then return end
  local happy, msg = req_sock:poll()
  if not happy then
    req_sock:close() -- good form
    req_sock = nil
    return
  end
  if msg then
    table.insert(parts, msg)
    print(part_order[#parts], parts[#parts])
  end
end)

FAQ

Why would I want this?

This is most useful for running from within the LuaJIT environment of a game, or other interactive-type application, where you don't have control over the overall program flow, but only get to run some Lua every frame or simulation 'tick'.

What makes this useful for mods?

nonblocking and callback free
simple to build, complete with TLS/WSS support, even on Windows
broad compatibility with LuaJIT binaries: no worrying about which compiler LuaJIT was built with
straightforward C API for easy use from FFIs

Can this be used outside of LuaJIT?

It can be used from anything that can link a C-API dynamic library (so in practice, anything with an FFI).

Building

Prebuilt binaries (including win32) are available from releases.

Pollnet builds with Rust in the standard way. Assuming you're on a 64 bit machine, building for 64 bit:

cargo build --release

However to use this from a 32 bit Windows binary (e.g., LuaJIT in a 32 bit application such as Noita, MWSE, etc.), you'll need to build for 32 bit:

rustup target add i686-pc-windows-msvc
cargo build --target=i686-pc-windows-msvc --release

The resulting .dll will end up in target/i686-pc-windows-msvc/release/pollnet.dll.

probable-basilisk / pollnet