node-gamedig/protocols/core.js

const EventEmitter = require('events').EventEmitter,
	dns = require('dns'),
	net = require('net'),
	async = require('async'),
	Reader = require('../lib/reader');

class Core extends EventEmitter {
	constructor() {
		super();
		this.options = {
			tcpTimeout: 1000,
			udpTimeout: 1000
		};
		this.maxAttempts = 1;
		this.attempt = 1;
		this.finished = false;
		this.encoding = 'utf8';
		this.byteorder = 'le';
		this.delimiter = '\0';

		this.globalTimeoutTimer = setTimeout(() => {
            this.fatal('timeout');
		},10000);
	}

	fatal(err,noretry) {
		if(!noretry && this.attempt < this.maxAttempts) {
			this.attempt++;
			this.start();
			return;
		}

		this.done({error: err.toString()});
	}

	initState() {
		return {
			name: '',
			map: '',
			password: false,

			raw: {},

			maxplayers: 0,
			players: [],
			bots: []
		};
	}

	finalizeState(state) {}

	finish(state) {
		this.finalizeState(state);
		this.done(state);
	}

	done(state) {
		if(this.finished) return;
		clearTimeout(this.globalTimeoutTimer);

		if(this.options.notes)
			state.notes = this.options.notes;

		state.query = {};
		if('host' in this.options) state.query.host = this.options.host;
		if('address' in this.options) state.query.address = this.options.address;
		if('port' in this.options) state.query.port = this.options.port;
		if('port_query' in this.options) state.query.port_query = this.options.port_query;
		state.query.type = this.type;
		if('pretty' in this) state.query.pretty = this.pretty;

		this.reset();
		this.finished = true;
		this.emit('finished',state);
		if(this.options.callback) this.options.callback(state);
	}

	reset() {
		if(this.timers) {
			for (const timer of this.timers) {
				clearTimeout(timer);
			}
		}
		this.timers = [];

		if(this.tcpSocket) {
			this.tcpSocket.destroy();
			delete this.tcpSocket;
		}

		this.udpTimeoutTimer = false;
		this.udpCallback = false;
	}

	start() {
		const options = this.options;
		this.reset();

		async.series([
			(c) => {
				// resolve host names
				if(!('host' in options)) return c();
				if(options.host.match(/\d+\.\d+\.\d+\.\d+/)) {
					options.address = options.host;
					c();
				} else {
                    this.parseDns(options.host,c);
				}
			},
			(c) => {
				// calculate query port if needed
				if(!('port_query' in options) && 'port' in options) {
					const offset = options.port_query_offset || 0;
					options.port_query = options.port + offset;
				}
				c();
			},
			(c) => {
				// run
				this.run(this.initState());
			}

		]);
	}

	parseDns(host,c) {
		const resolveStandard = (host,c) => {
			dns.lookup(host, (err,address,family) => {
				if(err) return this.fatal(err);
                this.options.address = address;
				c();
			});
		};

		const resolveSrv = (srv,host,c) => {
			dns.resolve(srv+'.'+host, 'SRV', (err,addresses) => {
				if(err) return resolveStandard(host,c);
				if(addresses.length >= 1) {
					const line = addresses[0];
                    this.options.port = line.port;
                    const srvhost = line.name;

					if(srvhost.match(/\d+\.\d+\.\d+\.\d+/)) {
                        this.options.address = srvhost;
						c();
					} else {
						// resolve yet again
						resolveStandard(srvhost,c);
					}
					return;
				}
				return resolveStandard(host,c);
			});
		};

		if(this.srvRecord) resolveSrv(this.srvRecord,host,c);
		else resolveStandard(host,c);
	}

	// utils
	/** @returns {Reader} */
	reader(buffer) {
		return new Reader(this,buffer);
	}
	translate(obj,trans) {
		for(const from of Object.keys(trans)) {
            const to = trans[from];
			if(from in obj) {
				if(to) obj[to] = obj[from];
				delete obj[from];
			}
		}
	}
	setTimeout(c,t) {
		if(this.finished) return 0;
		const id = setTimeout(c,t);
		this.timers.push(id);
		return id;
	}

	trueTest(str) {
		if(typeof str === 'boolean') return str;
		if(typeof str === 'number') return str !== 0;
		if(typeof str === 'string') {
			if(str.toLowerCase() === 'true') return true;
			if(str === 'yes') return true;
			if(str === '1') return true;
		}
		return false;
	}
	debugBuffer(buffer) {
		let out = '';
        let out2 = '';
		for(let i = 0; i < buffer.length; i++) {
			const sliced = buffer.slice(i,i+1);
			out += sliced.toString('hex')+' ';
            let chr = sliced.toString();
			if(chr < ' ' || chr > '~') chr = ' ';
			out2 += chr+'  ';
			if(out.length > 60) {
				console.log(out);
				console.log(out2);
				out = out2 = '';
			}
		}
		console.log(out);
		console.log(out2);
	}




	_tcpConnect(c) {
		if(this.tcpSocket) return c(this.tcpSocket);

		let connected = false;
		let received = Buffer.from([]);
		const address = this.options.address;
        const port = this.options.port_query;

        const socket = this.tcpSocket = net.connect(port,address,() => {
			if(this.debug) console.log(address+':'+port+" TCPCONNECTED");
			connected = true;
			c(socket);
		});
		socket.setTimeout(10000);
		socket.setNoDelay(true);
		if(this.debug) console.log(address+':'+port+" TCPCONNECT");

		const writeHook = socket.write;
		socket.write = (...args) => {
			if(this.debug) console.log(address+':'+port+" TCP--> "+args[0].toString('hex'));
			writeHook.apply(socket,args);
		};

		socket.on('error', () => {});
		socket.on('close', () => {
			if(!this.tcpCallback) return;
			if(connected) return this.fatal('Socket closed while waiting on TCP');
			else return this.fatal('TCP Connection Refused');
		});
		socket.on('data', (data) => {
			if(!this.tcpCallback) return;
			if(this.debug) console.log(address+':'+port+" <--TCP "+data.toString('hex'));
			received = Buffer.concat([received,data]);
			if(this.tcpCallback(received)) {
				clearTimeout(this.tcpTimeoutTimer);
                this.tcpCallback = false;
				received = Buffer.from([]);
			}
		});
	}
	tcpSend(buffer,ondata) {
		process.nextTick(() => {
			if(this.tcpCallback) return this.fatal('Attempted to send TCP packet while still waiting on a managed response');
            this._tcpConnect((socket) => {
				socket.write(buffer);
			});
			if(!ondata) return;

            this.tcpTimeoutTimer = this.setTimeout(() => {
                this.tcpCallback = false;
                this.fatal('TCP Watchdog Timeout');
			},this.options.tcpTimeout);
            this.tcpCallback = ondata;
		});
	}



	udpSend(buffer,onpacket,ontimeout) {
		process.nextTick(() => {
			if(this.udpCallback) return this.fatal('Attempted to send UDP packet while still waiting on a managed response');
            this._udpSendNow(buffer);
			if(!onpacket) return;

            this.udpTimeoutTimer = this.setTimeout(() => {
                this.udpCallback = false;
				let timeout = false;
				if(!ontimeout || ontimeout() !== true) timeout = true;
				if(timeout) this.fatal('UDP Watchdog Timeout');
			},this.options.udpTimeout);
            this.udpCallback = onpacket;
		});
	}
	_udpSendNow(buffer) {
		if(!('port_query' in this.options)) return this.fatal('Attempted to send without setting a port');
		if(!('address' in this.options)) return this.fatal('Attempted to send without setting an address');

		if(typeof buffer === 'string') buffer = Buffer.from(buffer,'binary');

		if(this.debug) console.log(this.options.address+':'+this.options.port_query+" UDP--> "+buffer.toString('hex'));
		this.udpSocket.send(buffer,0,buffer.length,this.options.port_query,this.options.address);
	}
	_udpResponse(buffer) {
		if(this.udpCallback) {
			const result = this.udpCallback(buffer);
			if(result === true) {
				// we're done with this udp session
				clearTimeout(this.udpTimeoutTimer);
				this.udpCallback = false;
			}
		} else {
			this.udpResponse(buffer);
		}
	}
	udpResponse() {}
}

module.exports = Core;