@league-bulk-buy/lcu-process-tools

Windows native process utilities for discovering the League of Legends Client (LCU) and reading its full command-line arguments — no C++ addon, no admin rights required.

How it works

Uses NtQueryInformationProcess(ProcessCommandLineInformation = 60) via koffi (a pure-JS FFI library).

Key advantage over PEB memory-reading approaches:

| Requirement | PEB approach | This package | |-------------|-------------|--------------| | PROCESS_VM_READ | ✅ Required | ❌ Not needed | | Admin / elevated | Sometimes | ❌ Never | | Works vs WeGame-elevated process | ❌ Often fails | ✅ Always works | | Native addon (.node) | Often | ❌ Pure JS FFI |

Platform: Windows x64 only (Windows 8.1 / Server 2012 R2+).

Installation

npm install @league-bulk-buy/lcu-process-tools

Requires Node.js ≥ 18 on Windows.

Usage

import { getPidsByName, getCommandLine, getProcessImagePath } from '@league-bulk-buy/lcu-process-tools';

// 1. Find all PIDs for a process name
const pids = getPidsByName('LeagueClientUx.exe');
console.log('PIDs:', pids);

// 2. Get the full command-line string (contains --remoting-auth-token, --app-port, etc.)
for (const pid of pids) {
  const cmdline = getCommandLine(pid);
  console.log(`PID ${pid} cmdline:`, cmdline);
}

// 3. Get the executable path
for (const pid of pids) {
  const imagePath = getProcessImagePath(pid);
  console.log(`PID ${pid} path:`, imagePath);
}

Parsing LCU auth info

import { getPidsByName, getCommandLine } from '@league-bulk-buy/lcu-process-tools';

function getLcuCredentials() {
  const pids = getPidsByName('LeagueClientUx.exe');
  for (const pid of pids) {
    const cmdline = getCommandLine(pid);
    if (!cmdline) continue;

    const port  = cmdline.match(/--app-port=(\d+)/)?.[1];
    const token = cmdline.match(/--remoting-auth-token=([\w-]+)/)?.[1];
    if (port && token) return { pid, port: Number(port), token };
  }
  return null;
}

API

getPidsByName(exeName: string): number[]

Returns all PIDs whose process image name matches exeName (case-insensitive).
Uses CreateToolhelp32Snapshot — no privileges required.

getCommandLine(pid: number): string | null

Returns the full command-line string for the given PID.
Uses NtQueryInformationProcess(ProcessCommandLineInformation) — only needs PROCESS_QUERY_LIMITED_INFORMATION (0x1000).
Returns null on failure.

getProcessImagePath(pid: number): string | null

Returns the full executable path for the given PID.
Uses QueryFullProcessImageNameW — only needs PROCESS_QUERY_LIMITED_INFORMATION.
Returns null on failure.

Credits

The NtQueryInformationProcess technique (class 60) is the same used by LeagueAkari's native C++ addon getCommandLine1. This package reimplements it in pure JavaScript via koffi.

License

MIT