node-gamedig/lib/typeresolver.js

const Path = require('path'),
	fs = require('fs');

const protocolDir = Path.normalize(__dirname+'/../protocols');
const gamesFile = Path.normalize(__dirname+'/../games.txt');

function parseList(str) {
	if(!str) return {};
    const out = {};
	for (const one of str.split(',')) {
        const equals = one.indexOf('=');
        const key = equals === -1 ? one : one.substr(0,equals);
		let value = equals === -1 ? '' : one.substr(equals+1);

		if(value === 'true' || value === '') value = true;
		else if(value === 'false') value = false;
		else if(!isNaN(value)) value = parseInt(value);

		out[key] = value;
	}
	return out;
}
function readGames() {
    const lines = fs.readFileSync(gamesFile,'utf8').split('\n');
    const games = {};

	for (let line of lines) {
		// strip comments
		const comment = line.indexOf('#');
		if(comment !== -1) line = line.substr(0,comment);
		line = line.trim();
		if(!line) continue;

		const split = line.split('|');

		games[split[0].trim()] = {
			pretty: split[1].trim(),
			protocol: split[2].trim(),
			options: parseList(split[3]),
			params: parseList(split[4])
		};
	}
	return games;
}
const games = readGames();

function createProtocolInstance(type) {
	type = Path.basename(type);

	const path = protocolDir+'/'+type;
	if(!fs.existsSync(path+'.js')) throw Error('Protocol definition file missing: '+type);
    const protocol = require(path);

	return new protocol();
}

class TypeResolver {
	static lookup(type) {
		if(!type) throw Error('No game specified');

		if(type.substr(0,9) === 'protocol-') {
			return createProtocolInstance(type.substr(9));
		}

        const game = games[type];
		if(!game) throw Error('Invalid game: '+type);

        const query = createProtocolInstance(game.protocol);
		query.pretty = game.pretty;
		for(const key of Object.keys(game.options)) {
            query.options[key] = game.options[key];
        }
		for(const key of Object.keys(game.params)) {
            query[key] = game.params[key];
        }

		return query;
	}
	static printReadme() {
		let out = '';
		for(const key of Object.keys(games)) {
			const game = games[key];
			out += "* "+game.pretty+" ("+key+")";
			if(game.options.port_query_offset || game.options.port_query)
				out += " [[Separate Query Port](#separate-query-port)]";
			if(game.params.doc_notes)
				out += " [[Additional Notes](#"+game.params.doc_notes+")]";
			out += "\n";
		}
		return out;
	}
}

module.exports = TypeResolver;