import { Server as WsServer, OPEN as SocketReady, } from 'ws'; import { createHash } from 'crypto'; import RateLimiter from './RateLimiter'; import { ServerConst } from '../utility/Constants'; /** * Main websocket server handling communications and connection events * @property {RateLimiter} police - Main rate limit handler * @property {String} cmdKey - Internal use command key * @author Marzavec ( https://github.com/marzavec ) * @version v2.0.0 * @license WTFPL ( http://www.wtfpl.net/txt/copying/ ) */ class MainServer extends WsServer { /** * Create a HackChat server instance * @param {CoreApp} core Reference to the global core object */ constructor(core) { super({ port: core.config.websocketPort }); /** * Stored reference to the core * @type {CoreApp} */ this.core = core; /** * Command key used to verify internal commands * @type {String} */ this.internalCmdKey = [...Array(Math.floor(Math.random() * 128) + 128)].map(() => (~~(Math.random() * 36)).toString(36)).join(''); /** * Salt used to hash a clients ip * @type {String} */ this.ipSalt = [...Array(Math.floor(Math.random() * 128) + 128)].map(() => (~~(Math.random() * 36)).toString(36)).join(''); /** * Data store for command hooks * @type {Object} */ this.hooks = {}; /** * Main rate limit tracker * @type {RateLimiter} */ this.police = new RateLimiter(); /** * Black listed command names * @type {Object} */ this.cmdBlacklist = {}; /** * Stored info about the last server error * @type {ErrorEvent} */ this.lastErr = null; this.setupServer(); this.loadHooks(); } /** * Internal command key getter. Used to verify that internal only commands * originate internally and not from a connected client * @todo Update to a structure that cannot be passed through json * @type {String} * @public * @readonly */ get cmdKey() { return this.internalCmdKey; } /** * Create ping interval and setup server event listeners * @private * @return {void} */ setupServer() { this.heartBeat = setInterval(() => this.beatHeart(), ServerConst.PulseSpeed); this.on('error', (err) => { this.handleError(err); }); this.on('connection', (socket, request) => { this.newConnection(socket, request); }); } /** * Send empty `ping` frame to each client * @private * @return {void} */ beatHeart() { const targetSockets = this.findSockets({}); if (targetSockets.length === 0) { return; } for (let i = 0, l = targetSockets.length; i < l; i += 1) { try { if (targetSockets[i].readyState === SocketReady) { targetSockets[i].ping(); } } catch (e) { /* yolo */ } } } /** * Bind listeners for the new socket created on connection to this class * @param {ws#WebSocket} socket New socket object * @param {Object} request Initial headers of the new connection * @private * @return {void} */ newConnection(socket, request) { const newSocket = socket; newSocket.address = request.headers['x-forwarded-for'] || request.connection.remoteAddress; newSocket.on('message', (data) => { this.handleData(socket, data); }); newSocket.on('close', () => { this.handleClose(socket); }); newSocket.on('error', (err) => { this.handleError(err); }); } /** * Handle incoming messages from clients, parse and check command, then hand-off * @param {ws#WebSocket} socket Calling socket object * @param {String} data Message sent from client * @private * @return {void} */ handleData(socket, data) { // Don't penalize yet, but check whether IP is rate-limited if (this.police.frisk(socket.address, 0)) { this.core.commands.handleCommand(this, socket, { cmd: 'socketreply', cmdKey: this.cmdKey, text: 'You are being rate-limited or blocked.', }); return; } // Penalize here, but don't do anything about it this.police.frisk(socket.address, 1); // Ignore ridiculously large packets if (data.length > 65536) { return; } // Start sent data verification let payload = null; try { payload = JSON.parse(data); } catch (e) { // Client sent malformed json, gtfo socket.close(); } if (payload === null) { return; } /** * @todo make the following more flexible * Issue #1: hard coded `cmd` check * Issue #2: hard coded `cmd` value checks */ if (typeof payload.cmd === 'undefined') { return; } if (typeof payload.cmd !== 'string') { return; } if (typeof socket.channel === 'undefined' && (payload.cmd !== 'join' && payload.cmd !== 'chat')) { return; } if (typeof this.cmdBlacklist[payload.cmd] === 'function') { return; } // End @todo // // Execute `in` (incoming data) hooks and process results payload = this.executeHooks('in', socket, payload); if (typeof payload === 'string') { // A hook malfunctioned, reply with error this.core.commands.handleCommand(this, socket, { cmd: 'socketreply', cmdKey: this.cmdKey, text: payload, }); return; } if (payload === false) { // A hook requested this data be dropped return; } // Finished verification & hooks, pass to command modules this.core.commands.handleCommand(this, socket, payload); } /** * Pass socket close event to disconnection command module * @param {ws#WebSocket} socket Closing socket object * @private * @return {void} */ handleClose(socket) { this.core.commands.handleCommand(this, socket, { cmd: 'disconnect', cmdKey: this.cmdKey, }); } /** * "Handle" server or socket errors * @param {ErrorEvent} err The sad stuff * @private * @return {void} */ handleError(err) { this.lastErr = err; console.log(`Server error: ${err}`); } /** * Send data payload to specific socket/client * @param {Object} payload Object to convert to json for transmission * @param {ws#WebSocket} socket The target client * @example * server.send({ * cmd: 'info', * text: 'Only targetSocket will see this' * }, targetSocket); * @public * @return {void} */ send(payload, socket) { let outgoingPayload = payload; // Add timestamp to command outgoingPayload.time = Date.now(); // Execute `in` (incoming data) hooks and process results outgoingPayload = this.executeHooks('out', socket, outgoingPayload); if (typeof outgoingPayload === 'string') { // A hook malfunctioned, reply with error this.core.commands.handleCommand(this, socket, { cmd: 'socketreply', cmdKey: this.cmdKey, text: outgoingPayload, }); return; } if (outgoingPayload === false) { // A hook requested this data be dropped return; } try { if (socket.readyState === SocketReady) { socket.send(JSON.stringify(outgoingPayload)); } } catch (e) { /* yolo */ } } /** * Overload function for `this.send()` * @param {Object} payload Object to convert to json for transmission * @param {ws#WebSocket} socket The target client * @example * server.reply({ * cmd: 'info', * text: 'Only targetSocket will see this' * }, targetSocket); * @public * @return {void} */ reply(payload, socket) { this.send(payload, socket); } /** * Finds sockets/clients that meet the filter requirements, then passes the data to them * @param {Object} payload Object to convert to json for transmission * @param {Object} filter see `this.findSockets()` * @example * server.broadcast({ * cmd: 'info', * text: 'Everyone in "programming" will see this' * }, { channel: 'programming' }); * @public * @return {Boolean} False if no clients matched the filter, true if data sent */ broadcast(payload, filter) { const targetSockets = this.findSockets(filter); if (targetSockets.length === 0) { return false; } for (let i = 0, l = targetSockets.length; i < l; i += 1) { this.send(payload, targetSockets[i]); } return true; } /** * Finds sockets/clients that meet the filter requirements, returns result as array * @param {Object} data Object to convert to json for transmission * @param {Object} filter The socket must of equal or greater attribs matching `filter` * @example * // match all sockets: * `filter` = {} * // match any socket where socket.channel === 'programming' * `filter` = { channel: 'programming' } * // match any socket where * // socket.channel === 'programming' && socket.nick === 'Marzavec' * `filter` = { channel: 'programming', nick: 'Marzavec' } * @public * @return {Array} Clients who matched the filter requirements */ findSockets(filter) { const filterAttribs = Object.keys(filter); const reqCount = filterAttribs.length; let curMatch; const matches = []; this.clients.forEach((socket) => { // for (const socket of this.clients) { curMatch = 0; for (let i = 0; i < reqCount; i += 1) { if (typeof socket[filterAttribs[i]] !== 'undefined') { switch (typeof filter[filterAttribs[i]]) { case 'object': { if (Array.isArray(filter[filterAttribs[i]])) { if (filter[filterAttribs[i]].indexOf(socket[filterAttribs[i]]) !== -1) { curMatch += 1; } } else if (socket[filterAttribs[i]] === filter[filterAttribs[i]]) { curMatch += 1; } break; } case 'function': { if (filter[filterAttribs[i]](socket[filterAttribs[i]])) { curMatch += 1; } break; } default: { if (socket[filterAttribs[i]] === filter[filterAttribs[i]]) { curMatch += 1; } break; } } } } if (curMatch === reqCount) { matches.push(socket); } }); return matches; } /** * Hashes target socket's remote address using non-static variable length salt * encodes and shortens the output, returns that value * @param {(ws#WebSocket|String)} target Either the target socket or ip as string * @example * let userHash = server.getSocketHash('1.2.3.4'); * let userHash = server.getSocketHash(client); * @public * @return {String} Hashed client connection string */ getSocketHash(target) { const sha = createHash('sha256'); if (typeof target === 'string') { sha.update(target + this.ipSalt); } else { sha.update(target.address + this.ipSalt); } return sha.digest('base64').substr(0, 15); } /** * (Re)loads all command module hooks, then sorts their order of operation by * priority, ascending (0 being highest priority) * @public * @return {void} */ loadHooks() { // clear current hooks (if any) this.clearHooks(); // notify each module to register their hooks (if any) this.core.commands.initCommandHooks(this); let curHooks = []; let hookObj = []; if (typeof this.hooks.in !== 'undefined') { // start sorting, with incoming first curHooks = [...this.hooks.in.keys()]; for (let i = 0, j = curHooks.length; i < j; i += 1) { hookObj = this.hooks.in.get(curHooks[i]); hookObj.sort((h1, h2) => h1.priority - h2.priority); this.hooks.in.set(hookObj); } } if (typeof this.hooks.out !== 'undefined') { // then outgoing curHooks = [...this.hooks.out.keys()]; for (let i = 0, j = curHooks.length; i < j; i += 1) { hookObj = this.hooks.out.get(curHooks[i]); hookObj.sort((h1, h2) => h1.priority - h2.priority); this.hooks.out.set(hookObj); } } } /** * Adds a target function to an array of hooks. Hooks are executed either before * processing user input (`in`) or before sending data back to the client (`out`) * and allows a module to modify each payload before moving forward * @param {String} type The type of event, typically `in` (incoming) or `out` (outgoing) * @param {String} command Should match the desired `cmd` attrib of the payload * @param {Function} hookFunction Target function to execute, should accept * `server`, `socket` and `payload` as parameters * @param {Number} priority Execution priority, hooks with priority 1 will be executed before * hooks with priority 200 for example * @example * // Create hook to add "and stuff" to every chat line * server.registerHook('in', 'chat', (server, socket, payload) => payload.text += ' and stuff'); * @public * @return {void} */ registerHook(type, command, hookFunction, priority = 25) { if (typeof this.hooks[type] === 'undefined') { this.hooks[type] = new Map(); } if (!this.hooks[type].has(command)) { this.hooks[type].set(command, []); } this.hooks[type].get(command).push({ run: hookFunction, priority, }); } /** * Loops through registered hooks & processes the results. Returned data will * be one of three possiblities: * A payload (modified or not) that will continue through the data flow * A boolean false to indicate halting the data through flow * A string which indicates an error occured in executing the hook * @param {String} type The type of event, typically `in` (incoming) or `out` (outgoing) * @param {ws#WebSocket} socket Either target client or client (depends on `type`) * @param {Object} payload Either incoming data from client or outgoing data (depends on `type`) * @private * @return {Object|Boolean} */ executeHooks(type, socket, payload) { const command = payload.cmd; let newPayload = payload; if (typeof this.hooks[type] !== 'undefined') { if (this.hooks[type].has(command)) { const hooks = this.hooks[type].get(command); for (let i = 0, j = hooks.length; i < j; i += 1) { try { newPayload = hooks[i].run(this.core, this, socket, newPayload); } catch (err) { const errText = `Hook failure, '${type}', '${command}': `; if (this.core.config.logErrDetailed === true) { console.log(errText + err.stack); } else { console.log(errText + err.toString()); } return errText + err.toString(); } // A hook function may choose to return false to prevent all further processing if (newPayload === false) { return false; } } } } return newPayload; } /** * Wipe server hooks to make ready for module reload calls * @public * @return {void} */ clearHooks() { this.hooks = {}; } } export default MainServer;