ping-minecraft-server/lib/index.js

Ping a Minecraft Server

"use strict";
const net_1 = require("net");
function itob(n, length) {
    const result = [];
    while (n > 0 || result.length < length) {
        const digit = n & 0xff;
        result.unshift(digit);
        n >>= 8;
    }
    return result;
}
class PingError extends Error {
    constructor(message, host, port) {
        super(message);
        this.host = host;
        this.port = port;
    }
}
function ping(host, port, options = {}) {
    const socket = new net_1.Socket();
    const PacketID = Buffer.from([0]);
    const ProtocolVersion = Buffer.from([242, 3]);
    const ServerAddressContent = Buffer.from(host, 'ascii');
    const ServerAddressLength = Buffer.from(itob(ServerAddressContent.length, 1));
    const ServerAddress = Buffer.concat([ServerAddressLength, ServerAddressContent]);
    const ServerPort = Buffer.from(itob(port, 2));
    const NextState = Buffer.from([1]);
    const HandshakePacketContent = Buffer.concat([PacketID, ProtocolVersion, ServerAddress, ServerPort, NextState]);
    const HandshakePacketLength = Buffer.from(itob(HandshakePacketContent.length, 1));
    const HandshakePacket = Buffer.concat([HandshakePacketLength, HandshakePacketContent]);
    const RequestPacket = Buffer.from([1, 0]);
    const { timeout = 5000 } = options;
    return new Promise((resolve, reject) => {
        let response = '';
        let bytes = 0;
        let length = -1;
        socket.on('data', (data) => {
            let offset = 0;
            if (length < 0) {
                const lowerByte = data[3];
                const higherByte = data[4];
                length = ((higherByte & 0x7f) << 7) | (lowerByte & 0x7f);
                offset = 5;
            }
            response += data.slice(offset).toString();
            bytes += data.slice(offset).length;
            if (bytes >= length) {
                try {
                    resolve(JSON.parse(response));
                }
                catch (error) {
                    reject(new PingError('parse-error', host, port));
                }
            }
        });
        socket.setTimeout(timeout, () => {
            socket.end();
            if (!response)
                reject(new PingError('connect-timeout', host, port));
        });
        socket.on('error', () => {
            socket.destroy();
            reject(new PingError('connect-error', host, port));
        });
        socket.connect(port, host, () => {
            socket.write(HandshakePacket);
            socket.write(RequestPacket);
        });
    });
}
(function (ping) {
    ping.Error = PingError;
})(ping || (ping = {}));
module.exports = ping;