minestat.js

// Taken from https://github.com/FragLand/minestat/blob/master/JavaScript/minestat.js on April 9th 2020

/*
* minestat.js - A Minecraft server status checker
* Copyright (C) 2016 Lloyd Dilley
* http://www.dilley.me/
*
* This program is free software you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

// For use with Node.js

const NUM_FIELDS = 6      // number of values expected from server
const DEFAULT_TIMEOUT = 5 // default TCP timeout in seconds
address = null
port = null
online = null             // online or offline?
version = null            // server version
motd = null               // message of the day
current_players = null    // current number of players online
max_players = null        // maximum player capacity
latency = null            // ping time to server in milliseconds

const err = console.error
const log = console.log

module.exports = {
	init: function (address, port, timeout, callback) {
		this.address = address
		this.port = port

		if (typeof(timeout) === typeof(Function())) {
			callback = timeout
			timeout = DEFAULT_TIMEOUT
		}

		const net = require('net')
		var start_time = new Date()
		const client = net.connect(port, address, () => {
			this.latency = Math.round(new Date() - start_time)
			var buff = Buffer.from([ 0xFE, 0x01 ])
			client.write(buff)
		})

		client.setTimeout(timeout * 1000)

		client.on('data', (data) => {
			if (data != null && data != '') {
				var server_info = data.toString().split('\x00\x00\x00')
				if (server_info != null && server_info.length >= NUM_FIELDS) {
					this.online = true
					this.version = server_info[2].replace(/\u0000/g, '')
					this.motd = server_info[3].replace(/\u0000/g, '')
					this.current_players = server_info[4].replace(/\u0000/g, '')
					this.max_players = server_info[5].replace(/\u0000/g, '')
					callback(1)
				} else {
					this.online = false
					callback(0)
				}
			} else {
				callback(0)
			}

			client.end()
		})

		client.on('timeout', () => {
			callback(0)
			client.end()
		})

		client.on('end', () => {
			// Called on client.end()
		})

		client.on('error', (error) => {
			if (error.code == 'ENOTFOUND') {
				err('Unable to resolve ' + this.address + '.')
				return
			}

			if (error.code == 'ECONNREFUSED') {
				err('Unable to connect to port ' + this.port + '.')
				return
			}

			callback(0)
		})
	}
}