rsrpc~

rsrpc is a high-performance, drop-in replacement for arRPC written in Rust. It provides a Discord Rich Presence server with significantly lower resource usage, faster process detection, and dual protocol support.

🚀 Features

• Drop-in arRPC Replacement: 100% compatible with arRPC's JSON interface (WebSocket port 1337).
• MessagePack Support: Optional secondary server on port 1338 using MessagePack for ~25% smaller payloads.
• Fast Process Detection: Uses sysinfo native bindings (faster than wmic subprocess calls, doesn't spawn subprocesses).
• Dual Transports: Supports both IPC (named pipes/unix sockets) and WebSocket (ports 6463-6472).

🛠️ Installation & Building

Prerequisites

• Windows or Linux
• Rust and Cargo (for building from source)

Installation

Binaries: Grab the latest nightly binary from the Releases page. We provide builds for Windows (x64, arm64) and Linux (x64, arm64).

From Source:

git clone https://github.com/pog5/rsrpc.git
cd rsrpc
cargo build --release

📖 Usage

./rsrpc [OPTIONS]

Configuration

rsrpc can be configured via Command Line Arguments (flags) or Environment Variables. Flags take precedence.

Flag	Env Variable	Default	Description
--bridge-port <PORT>	RSRPC_BRIDGE_PORT	1337	Port for JSON bridge
--msgpack-port <PORT>	RSRPC_MSGPACK_PORT	1338	Port for MessagePack bridge
--enable-db-update	RSRPC_ENABLE_DB_UPDATE	false	Enable startup DB fetch
--no-process-scanning	RSRPC_NO_PROCESS_SCANNING	false	Disable game detection
--debug	RSRPC_DEBUG	false	Enable verbose logging

Database Updates

By default, rsrpc uses a bundled database of games for instant startup and zero network dependency. To enable runtime updates (fetching the latest list from Discord):

./rsrpc --enable-db-update

🔌 Integration

Vencord / Vesktop

rsrpc works out of the box with Vencord's WebRichPresence plugin due to its arRPC compatibility. Just enable the plugin and ensure rsrpc is running.

Custom Clients (JavaScript)

You can connect using standard WebSocket:

// Connect to standard JSON bridge
const ws = new WebSocket('ws://127.0.0.1:1337');
ws.onmessage = (msg) => console.log(JSON.parse(msg.data));

Or use the optimized MessagePack interface (requires @msgpack/msgpack):

import { decode } from '@msgpack/msgpack';
const ws = new WebSocket('ws://127.0.0.1:1338?format=msgpack');
ws.binaryType = 'arraybuffer';
ws.onmessage = (msg) => console.log(decode(new Uint8Array(msg.data)));

🏗️ Architecture

• Server: Orchestrates transports and process scanning.
• Transports:
  • IPC: Handles local Discord client communication (\\.\pipe\discord-ipc-0 or /tmp/discord-ipc-0).
  • WebSocket: Mimics local Discord WebSocket server (ports 6463-6472).
• Process Scanner: Periodically scans running processes against a local cache of detectable.json.
• Bridge: Broadcasts activity updates to connected web clients (e.g., Vencord).

📊 Comparison vs arRPC

Feature	arRPC (Node.js)	rsrpc (Rust)
Memory Usage	10GB.	10MB
Executable Size	~125MB (when bundled with Bun)	~3 MB (Standalone, Windows)
Process Scan	powershell + wmic	sysinfo
Protocols	JSON	JSON + MessagePack

📜 License

GPLv3 License. See LICENSE for details.