aboutsummaryrefslogtreecommitdiffstats
path: root/server/src/serverLib/MainServer.js
blob: c7a4bbe899cb90819274263e466bb22c1573acfc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
/**
  * Main websocket server handling communications and connection events
  *
  * Version: v2.0.0
  * Developer: Marzavec ( https://github.com/marzavec )
  * License: WTFPL ( http://www.wtfpl.net/txt/copying/ )
  *
  */

const WsServer = require('ws').Server;
const SocketReady = require('ws').OPEN;
const Crypto = require('crypto');
const RateLimiter = require('./RateLimiter');
const PulseSpeed = 16000; // ping all clients every X ms
const IpSalt = [...Array(Math.floor(Math.random()*128)+128)].map(i=>(~~(Math.random()*36)).toString(36)).join('');
const InternalCmdKey = [...Array(Math.floor(Math.random()*128)+128)].map(i=>(~~(Math.random()*36)).toString(36)).join('');

class MainServer extends WsServer {
  /**
   * Create a HackChat server instance.
   *
   * @param {Object} core Reference to the global core object
   */
  constructor (core) {
    super({ port: core.config.websocketPort });

    this.core = core;
    this.hooks = {};
    this.police = new RateLimiter();
    this.cmdBlacklist = {};

    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} readonly
    */
  get cmdKey () {
    return InternalCmdKey;
  }

  /**
    * Create ping interval and setup server event listeners
    *
    */
  setupServer () {
    this.heartBeat = setInterval(() => this.beatHeart(), PulseSpeed);

    this.on('error', (err) => {
      this.handleError('server', err);
    });

    this.on('connection', (socket, request) => {
      this.newConnection(socket, request);
    });
  }

  /**
    * Send empty `ping` frame to each client
    *
    */
  beatHeart () {
    let targetSockets = this.findSockets({});

    if (targetSockets.length === 0) {
      return;
    }

    for (let i = 0, l = targetSockets.length; i < l; i++) {
      try {
        if (targetSockets[i].readyState === SocketReady) {
          targetSockets[i].ping();
        }
      } catch (e) { }
    }
  }

  /**
    * Bind listeners for the new socket created on connection to this class
    *
    * @param {Object} socket New socket object
    * @param {Object} request Initial headers of the new connection
    */
  newConnection (socket, request) {
    socket.remoteAddress = request.headers['x-forwarded-for'] || request.connection.remoteAddress;

  	socket.on('message', (data) => {
      this.handleData(socket, data);
    });

    socket.on('close', () => {
      this.handleClose(socket);
    });

    socket.on('error', (err) => {
      this.handleError(socket, err);
    });
  }

  /**
    * Handle incoming messages from clients, parse and check command, then hand-off
    *
    * @param {Object} socket Calling socket object
    * @param {String} data Message sent from client
    */
  handleData (socket, data) {
    // Don't penalize yet, but check whether IP is rate-limited
    if (this.police.frisk(socket.remoteAddress, 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.remoteAddress, 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 this 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;
    } else 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);
  }

  /**
    * Handle socket close from clients
    *
    * @param {Object} socket Closing socket object
    */
  handleClose (socket) {
    this.core.commands.handleCommand(this, socket, {
      cmd: 'disconnect',
      cmdKey: this.cmdKey
    });
  }

  /**
    * "Handle" server or socket errors
    *
    * @param {Object||String} socket Calling socket object, or 'server'
    * @param {String} err The sad stuff
    */
  handleError (socket, err) {
    console.log(`Server error: ${err}`);
  }

  /**
    * Send data payload to specific socket/client
    *
    * @param {Object} payload Object to convert to json for transmission
    * @param {Object} socket The target client
    */
  send (payload, socket) {
    // Add timestamp to command
    payload.time = Date.now();

    // Execute `in` (incoming data) hooks and process results
    payload = this.executeHooks('out', 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;
    } else if (payload === false) {
      // A hook requested this data be dropped
      return;
    }

    try {
      if (socket.readyState === SocketReady) {
        socket.send(JSON.stringify(payload));
      }
    } catch (e) { }
  }

  /**
    * Overload function for `this.send()`
    *
    * @param {Object} payload Object to convert to json for transmission
    * @param {Object} socket The target client
    */
  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()`
    *
    * @return {Boolean} False if no clients matched the filter, true if data sent
    */
  broadcast (payload, filter) {
    let targetSockets = this.findSockets(filter);

    if (targetSockets.length === 0) {
      return false;
    }

    for (let i = 0, l = targetSockets.length; i < l; i++) {
      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`
    *                        = {} // matches all
    *                        = { channel: 'programming' } // matches any socket where (`socket.channel` === 'programming')
    *                        = { channel: 'programming', nick: 'Marzavec' } // matches any socket where (`socket.channel` === 'programming' && `socket.nick` === 'Marzavec')
    *
    * @return {Array} Clients who matched the filter requirements
    */
  findSockets (filter) {
    let filterAttribs = Object.keys(filter);
    let reqCount = filterAttribs.length;
    let curMatch;
    let matches = [];
    for ( let socket of this.clients ) {
      curMatch = 0;

      for (let i = 0; i < reqCount; i++) {
        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++;
                }
              } else {
                if (socket[filterAttribs[i]] === filter[filterAttribs[i]]) {
                  curMatch++;
                }
              }
            break;
            }

            case 'function': {
              if (filter[filterAttribs[i]](socket[filterAttribs[i]])) {
                curMatch++;
              }
            break;
            }

            default: {
              if (socket[filterAttribs[i]] === filter[filterAttribs[i]]) {
                curMatch++;
              }
            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 {Object||String} target Either the target socket or ip as string
    *
    * @return {String} Hashed client connection string
    */
  getSocketHash (target) {
    let sha = Crypto.createHash('sha256');

    if (typeof target === 'string') {
      sha.update(target + IpSalt);
    } else {
      sha.update(target.remoteAddress + 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)
    *
    */
  loadHooks () {
    // clear current hooks (if any)
    this.clearHooks();
    // notify each module to register their hooks (if any)
    this.core.commands.initCommandHooks(this);

    if (typeof this.hooks['in'] !== 'undefined') {
      // start sorting, with incoming first
      let curHooks = [ ...this.hooks['in'].keys() ];
      let hookObj = [];
      for (let i = 0, j = curHooks.length; i < j; i++) {
        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++) {
        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
    */
  registerHook (type, command, hookFunction, priority) {
    if (typeof priority === 'undefined') {
      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: 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 {Object} socket Either the target client or the client triggering the hook (depending on `type`)
    * @param {Object} payload Either incoming data from client or outgoing data (depending on `type`)
    *
    * @return {Object || Boolean}
    */
  executeHooks (type, socket, payload) {
    let command = payload.cmd;

    if (typeof this.hooks[type] !== 'undefined') {
      if (this.hooks[type].has(command)) {
        let hooks = this.hooks[type].get(command);

        for (let i = 0, j = hooks.length; i < j; i++) {
          try {
            payload = hooks[i].run(this.core, this, socket, payload);
          } catch (err) {
            let errText = `Hook failure, '${type}', '${command}': ${err}`;
            console.log(errText);
            return errText;
          }

          // A hook function may choose to return false to prevent all further processing
          if (payload === false) {
            return false;
          }
        }
      }
    }

    return payload;
  }

  /**
    * Wipe server hooks to make ready for module reload calls
    *
    */
  clearHooks () {
    this.hooks = {};
  }
}

module.exports = MainServer;