summaryrefslogtreecommitdiff
path: root/lib/realtime.js
blob: c731e5b07033f2174acd151263f1d97d69e580b4 (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
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
'use strict'
// realtime
// external modules
var cookie = require('cookie')
var cookieParser = require('cookie-parser')
var url = require('url')
var async = require('async')
var LZString = require('lz-string')
var randomcolor = require('randomcolor')
var Chance = require('chance')
var chance = new Chance()
var moment = require('moment')

// core
var config = require('./config')
var logger = require('./logger')
var history = require('./history')
var models = require('./models')

// ot
var ot = require('./ot')

// public
var realtime = {
  io: null,
  onAuthorizeSuccess: onAuthorizeSuccess,
  onAuthorizeFail: onAuthorizeFail,
  secure: secure,
  connection: connection,
  getStatus: getStatus,
  isReady: isReady,
  maintenance: true
}

function onAuthorizeSuccess (data, accept) {
  accept()
}

function onAuthorizeFail (data, message, error, accept) {
  accept() // accept whether authorize or not to allow anonymous usage
}

// secure the origin by the cookie
function secure (socket, next) {
  try {
    var handshakeData = socket.request
    if (handshakeData.headers.cookie) {
      handshakeData.cookie = cookie.parse(handshakeData.headers.cookie)
      handshakeData.sessionID = cookieParser.signedCookie(handshakeData.cookie[config.sessionname], config.sessionsecret)
      if (handshakeData.sessionID &&
                handshakeData.cookie[config.sessionname] &&
                handshakeData.cookie[config.sessionname] !== handshakeData.sessionID) {
        if (config.debug) { logger.info('AUTH success cookie: ' + handshakeData.sessionID) }
        return next()
      } else {
        next(new Error('AUTH failed: Cookie is invalid.'))
      }
    } else {
      next(new Error('AUTH failed: No cookie transmitted.'))
    }
  } catch (ex) {
    next(new Error('AUTH failed:' + JSON.stringify(ex)))
  }
}

function emitCheck (note) {
  var out = {
    title: note.title,
    updatetime: note.updatetime,
    lastchangeuser: note.lastchangeuser,
    lastchangeuserprofile: note.lastchangeuserprofile,
    authors: note.authors,
    authorship: note.authorship
  }
  realtime.io.to(note.id).emit('check', out)
}

// actions
var users = {}
var notes = {}
// update when the note is dirty
setInterval(function () {
  async.each(Object.keys(notes), function (key, callback) {
    var note = notes[key]
    if (note.server.isDirty) {
      if (config.debug) logger.info('updater found dirty note: ' + key)
      note.server.isDirty = false
      updateNote(note, function (err, _note) {
        // handle when note already been clean up
        if (!notes[key] || !notes[key].server) return callback(null, null)
        if (!_note) {
          realtime.io.to(note.id).emit('info', {
            code: 404
          })
          logger.error('note not found: ', note.id)
        }
        if (err || !_note) {
          for (var i = 0, l = note.socks.length; i < l; i++) {
            var sock = note.socks[i]
            if (typeof sock !== 'undefined' && sock) {
              setTimeout(function () {
                sock.disconnect(true)
              }, 0)
            }
          }
          return callback(err, null)
        }
        note.updatetime = moment(_note.lastchangeAt).valueOf()
        emitCheck(note)
        return callback(null, null)
      })
    } else {
      return callback(null, null)
    }
  }, function (err) {
    if (err) return logger.error('updater error', err)
  })
}, 1000)

function updateNote (note, callback) {
  models.Note.findOne({
    where: {
      id: note.id
    }
  }).then(function (_note) {
    if (!_note) return callback(null, null)
    // update user note history
    var tempUsers = Object.assign({}, note.tempUsers)
    note.tempUsers = {}
    Object.keys(tempUsers).forEach(function (key) {
      updateHistory(key, note, tempUsers[key])
    })
    if (note.lastchangeuser) {
      if (_note.lastchangeuserId !== note.lastchangeuser) {
        models.User.findOne({
          where: {
            id: note.lastchangeuser
          }
        }).then(function (user) {
          if (!user) return callback(null, null)
          note.lastchangeuserprofile = models.User.getProfile(user)
          return finishUpdateNote(note, _note, callback)
        }).catch(function (err) {
          logger.error(err)
          return callback(err, null)
        })
      } else {
        return finishUpdateNote(note, _note, callback)
      }
    } else {
      note.lastchangeuserprofile = null
      return finishUpdateNote(note, _note, callback)
    }
  }).catch(function (err) {
    logger.error(err)
    return callback(err, null)
  })
}

function finishUpdateNote (note, _note, callback) {
  if (!note || !note.server) return callback(null, null)
  var body = note.server.document
  var title = note.title = models.Note.parseNoteTitle(body)
  var values = {
    title: title,
    content: body,
    authorship: note.authorship,
    lastchangeuserId: note.lastchangeuser,
    lastchangeAt: Date.now()
  }
  _note.update(values).then(function (_note) {
    saverSleep = false
    return callback(null, _note)
  }).catch(function (err) {
    logger.error(err)
    return callback(err, null)
  })
}

// clean when user not in any rooms or user not in connected list
setInterval(function () {
  async.each(Object.keys(users), function (key, callback) {
    var socket = realtime.io.sockets.connected[key]
    if ((!socket && users[key]) ||
      (socket && (!socket.rooms || socket.rooms.length <= 0))) {
      if (config.debug) { logger.info('cleaner found redundant user: ' + key) }
      if (!socket) {
        socket = {
          id: key
        }
      }
      disconnectSocketQueue.push(socket)
      disconnect(socket)
    }
    return callback(null, null)
  }, function (err) {
    if (err) return logger.error('cleaner error', err)
  })
}, 60000)

var saverSleep = false
// save note revision in interval
setInterval(function () {
  if (saverSleep) return
  models.Revision.saveAllNotesRevision(function (err, notes) {
    if (err) return logger.error('revision saver failed: ' + err)
    if (notes && notes.length <= 0) {
      saverSleep = true
    }
  })
}, 60000 * 5)

function getStatus (callback) {
  models.Note.count().then(function (notecount) {
    var distinctaddresses = []
    var regaddresses = []
    var distinctregaddresses = []
    Object.keys(users).forEach(function (key) {
      var user = users[key]
      if (!user) return
      let found = false
      for (let i = 0; i < distinctaddresses.length; i++) {
        if (user.address === distinctaddresses[i]) {
          found = true
          break
        }
      }
      if (!found) {
        distinctaddresses.push(user.address)
      }
      if (user.login) {
        regaddresses.push(user.address)
        let found = false
        for (let i = 0; i < distinctregaddresses.length; i++) {
          if (user.address === distinctregaddresses[i]) {
            found = true
            break
          }
        }
        if (!found) {
          distinctregaddresses.push(user.address)
        }
      }
    })
    models.User.count().then(function (regcount) {
      return callback ? callback({
        onlineNotes: Object.keys(notes).length,
        onlineUsers: Object.keys(users).length,
        distinctOnlineUsers: distinctaddresses.length,
        notesCount: notecount,
        registeredUsers: regcount,
        onlineRegisteredUsers: regaddresses.length,
        distinctOnlineRegisteredUsers: distinctregaddresses.length,
        isConnectionBusy: isConnectionBusy,
        connectionSocketQueueLength: connectionSocketQueue.length,
        isDisconnectBusy: isDisconnectBusy,
        disconnectSocketQueueLength: disconnectSocketQueue.length
      }) : null
    }).catch(function (err) {
      return logger.error('count user failed: ' + err)
    })
  }).catch(function (err) {
    return logger.error('count note failed: ' + err)
  })
}

function isReady () {
  return realtime.io &&
    Object.keys(notes).length === 0 && Object.keys(users).length === 0 &&
    connectionSocketQueue.length === 0 && !isConnectionBusy &&
    disconnectSocketQueue.length === 0 && !isDisconnectBusy
}

function extractNoteIdFromSocket (socket) {
  if (!socket || !socket.handshake || !socket.handshake.headers) {
    return false
  }
  var referer = socket.handshake.headers.referer
  if (!referer) {
    return false
  }
  var hostUrl = url.parse(referer)
  var noteId = config.urlpath ? hostUrl.pathname.slice(config.urlpath.length + 1, hostUrl.pathname.length).split('/')[1] : hostUrl.pathname.split('/')[1]
  return noteId
}

function parseNoteIdFromSocket (socket, callback) {
  var noteId = extractNoteIdFromSocket(socket)
  if (!noteId) {
    return callback(null, null)
  }
  models.Note.parseNoteId(noteId, function (err, id) {
    if (err || !id) return callback(err, id)
    return callback(null, id)
  })
}

function emitOnlineUsers (socket) {
  var noteId = socket.noteId
  if (!noteId || !notes[noteId]) return
  var users = []
  Object.keys(notes[noteId].users).forEach(function (key) {
    var user = notes[noteId].users[key]
    if (user) { users.push(buildUserOutData(user)) }
  })
  var out = {
    users: users
  }
  realtime.io.to(noteId).emit('online users', out)
}

function emitUserStatus (socket) {
  var noteId = socket.noteId
  var user = users[socket.id]
  if (!noteId || !notes[noteId] || !user) return
  var out = buildUserOutData(user)
  socket.broadcast.to(noteId).emit('user status', out)
}

function emitRefresh (socket) {
  var noteId = socket.noteId
  if (!noteId || !notes[noteId]) return
  var note = notes[noteId]
  var out = {
    title: note.title,
    docmaxlength: config.documentmaxlength,
    owner: note.owner,
    ownerprofile: note.ownerprofile,
    lastchangeuser: note.lastchangeuser,
    lastchangeuserprofile: note.lastchangeuserprofile,
    authors: note.authors,
    authorship: note.authorship,
    permission: note.permission,
    createtime: note.createtime,
    updatetime: note.updatetime
  }
  socket.emit('refresh', out)
}

function isDuplicatedInSocketQueue (queue, socket) {
  for (var i = 0; i < queue.length; i++) {
    if (queue[i] && queue[i].id === socket.id) {
      return true
    }
  }
  return false
}

function clearSocketQueue (queue, socket) {
  for (var i = 0; i < queue.length; i++) {
    if (!queue[i] || queue[i].id === socket.id) {
      queue.splice(i, 1)
      i--
    }
  }
}

function connectNextSocket () {
  setTimeout(function () {
    isConnectionBusy = false
    if (connectionSocketQueue.length > 0) {
      startConnection(connectionSocketQueue[0])
    }
  }, 1)
}

function interruptConnection (socket, noteId, socketId) {
  if (notes[noteId]) delete notes[noteId]
  if (users[socketId]) delete users[socketId]
  if (socket) { clearSocketQueue(connectionSocketQueue, socket) } else { connectionSocketQueue.shift() }
  connectNextSocket()
}

function checkViewPermission (req, note) {
  if (note.permission === 'private') {
    if (req.user && req.user.logged_in && req.user.id === note.owner) { return true } else { return false }
  } else if (note.permission === 'limited' || note.permission === 'protected') {
    if (req.user && req.user.logged_in) { return true } else { return false }
  } else {
    return true
  }
}

var isConnectionBusy = false
var connectionSocketQueue = []
var isDisconnectBusy = false
var disconnectSocketQueue = []

function finishConnection (socket, noteId, socketId) {
  // if no valid info provided will drop the client
  if (!socket || !notes[noteId] || !users[socketId]) {
    return interruptConnection(socket, noteId, socketId)
  }
  // check view permission
  if (!checkViewPermission(socket.request, notes[noteId])) {
    interruptConnection(socket, noteId, socketId)
    return failConnection(403, 'connection forbidden', socket)
  }
  let note = notes[noteId]
  let user = users[socketId]
  // update user color to author color
  if (note.authors[user.userid]) {
    user.color = users[socket.id].color = note.authors[user.userid].color
  }
  note.users[socket.id] = user
  note.socks.push(socket)
  note.server.addClient(socket)
  note.server.setName(socket, user.name)
  note.server.setColor(socket, user.color)

  // update user note history
  updateHistory(user.userid, note)

  emitOnlineUsers(socket)
  emitRefresh(socket)

  // clear finished socket in queue
  clearSocketQueue(connectionSocketQueue, socket)
  // seek for next socket
  connectNextSocket()

  if (config.debug) {
    let noteId = socket.noteId
    logger.info('SERVER connected a client to [' + noteId + ']:')
    logger.info(JSON.stringify(user))
    // logger.info(notes);
    getStatus(function (data) {
      logger.info(JSON.stringify(data))
    })
  }
}

function startConnection (socket) {
  if (isConnectionBusy) return
  isConnectionBusy = true

  var noteId = socket.noteId
  if (!noteId) {
    return failConnection(404, 'note id not found', socket)
  }

  if (!notes[noteId]) {
    var include = [{
      model: models.User,
      as: 'owner'
    }, {
      model: models.User,
      as: 'lastchangeuser'
    }, {
      model: models.Author,
      as: 'authors',
      include: [{
        model: models.User,
        as: 'user'
      }]
    }]

    models.Note.findOne({
      where: {
        id: noteId
      },
      include: include
    }).then(function (note) {
      if (!note) {
        return failConnection(404, 'note not found', socket)
      }
      var owner = note.ownerId
      var ownerprofile = note.owner ? models.User.getProfile(note.owner) : null

      var lastchangeuser = note.lastchangeuserId
      var lastchangeuserprofile = note.lastchangeuser ? models.User.getProfile(note.lastchangeuser) : null

      var body = note.content
      var createtime = note.createdAt
      var updatetime = note.lastchangeAt
      var server = new ot.EditorSocketIOServer(body, [], noteId, ifMayEdit, operationCallback)

      var authors = {}
      for (var i = 0; i < note.authors.length; i++) {
        var author = note.authors[i]
        var profile = models.User.getProfile(author.user)
        authors[author.userId] = {
          userid: author.userId,
          color: author.color,
          photo: profile.photo,
          name: profile.name
        }
      }

      notes[noteId] = {
        id: noteId,
        alias: note.alias,
        title: note.title,
        owner: owner,
        ownerprofile: ownerprofile,
        permission: note.permission,
        lastchangeuser: lastchangeuser,
        lastchangeuserprofile: lastchangeuserprofile,
        socks: [],
        users: {},
        tempUsers: {},
        createtime: moment(createtime).valueOf(),
        updatetime: moment(updatetime).valueOf(),
        server: server,
        authors: authors,
        authorship: note.authorship
      }

      return finishConnection(socket, noteId, socket.id)
    }).catch(function (err) {
      return failConnection(500, err, socket)
    })
  } else {
    return finishConnection(socket, noteId, socket.id)
  }
}

function failConnection (code, err, socket) {
  logger.error(err)
  // clear error socket in queue
  clearSocketQueue(connectionSocketQueue, socket)
  connectNextSocket()
  // emit error info
  socket.emit('info', {
    code: code
  })
  return socket.disconnect(true)
}

function disconnect (socket) {
  if (isDisconnectBusy) return
  isDisconnectBusy = true

  if (config.debug) {
    logger.info('SERVER disconnected a client')
    logger.info(JSON.stringify(users[socket.id]))
  }

  if (users[socket.id]) {
    delete users[socket.id]
  }
  var noteId = socket.noteId
  var note = notes[noteId]
  if (note) {
    // delete user in users
    if (note.users[socket.id]) {
      delete note.users[socket.id]
    }
    // remove sockets in the note socks
    do {
      var index = note.socks.indexOf(socket)
      if (index !== -1) {
        note.socks.splice(index, 1)
      }
    } while (index !== -1)
    // remove note in notes if no user inside
    if (Object.keys(note.users).length <= 0) {
      if (note.server.isDirty) {
        updateNote(note, function (err, _note) {
          if (err) return logger.error('disconnect note failed: ' + err)
          // clear server before delete to avoid memory leaks
          note.server.document = ''
          note.server.operations = []
          delete note.server
          delete notes[noteId]
          if (config.debug) {
            // logger.info(notes);
            getStatus(function (data) {
              logger.info(JSON.stringify(data))
            })
          }
        })
      } else {
        delete note.server
        delete notes[noteId]
      }
    }
  }
  emitOnlineUsers(socket)

  // clear finished socket in queue
  clearSocketQueue(disconnectSocketQueue, socket)
  // seek for next socket
  isDisconnectBusy = false
  if (disconnectSocketQueue.length > 0) { disconnect(disconnectSocketQueue[0]) }

  if (config.debug) {
    // logger.info(notes);
    getStatus(function (data) {
      logger.info(JSON.stringify(data))
    })
  }
}

function buildUserOutData (user) {
  var out = {
    id: user.id,
    login: user.login,
    userid: user.userid,
    photo: user.photo,
    color: user.color,
    cursor: user.cursor,
    name: user.name,
    idle: user.idle,
    type: user.type
  }
  return out
}

function updateUserData (socket, user) {
  // retrieve user data from passport
  if (socket.request.user && socket.request.user.logged_in) {
    var profile = models.User.getProfile(socket.request.user)
    user.photo = profile.photo
    user.name = profile.name
    user.userid = socket.request.user.id
    user.login = true
  } else {
    user.userid = null
    user.name = 'Guest ' + chance.last()
    user.login = false
  }
}

function ifMayEdit (socket, callback) {
  var noteId = socket.noteId
  if (!noteId || !notes[noteId]) return
  var note = notes[noteId]
  var mayEdit = true
  switch (note.permission) {
    case 'freely':
      // not blocking anyone
      break
    case 'editable': case 'limited':
      // only login user can change
      if (!socket.request.user || !socket.request.user.logged_in) { mayEdit = false }
      break
    case 'locked': case 'private': case 'protected':
      // only owner can change
      if (!note.owner || note.owner !== socket.request.user.id) { mayEdit = false }
      break
  }
  // if user may edit and this is a text operation
  if (socket.origin === 'operation' && mayEdit) {
    // save for the last change user id
    if (socket.request.user && socket.request.user.logged_in) {
      note.lastchangeuser = socket.request.user.id
    } else {
      note.lastchangeuser = null
    }
  }
  return callback(mayEdit)
}

function operationCallback (socket, operation) {
  var noteId = socket.noteId
  if (!noteId || !notes[noteId]) return
  var note = notes[noteId]
  var userId = null
  // save authors
  if (socket.request.user && socket.request.user.logged_in) {
    var user = users[socket.id]
    if (!user) return
    userId = socket.request.user.id
    if (!note.authors[userId]) {
      models.Author.findOrCreate({
        where: {
          noteId: noteId,
          userId: userId
        },
        defaults: {
          noteId: noteId,
          userId: userId,
          color: user.color
        }
      }).spread(function (author, created) {
        if (author) {
          note.authors[author.userId] = {
            userid: author.userId,
            color: author.color,
            photo: user.photo,
            name: user.name
          }
        }
      }).catch(function (err) {
        return logger.error('operation callback failed: ' + err)
      })
    }
    note.tempUsers[userId] = Date.now()
  }
  // save authorship - use timer here because it's an O(n) complexity algorithm
  setImmediate(function () {
    note.authorship = models.Note.updateAuthorshipByOperation(operation, userId, note.authorship)
  })
}

function updateHistory (userId, note, time) {
  var noteId = note.alias ? note.alias : LZString.compressToBase64(note.id)
  if (note.server) history.updateHistory(userId, noteId, note.server.document, time)
}

function connection (socket) {
  if (realtime.maintenance) return
  parseNoteIdFromSocket(socket, function (err, noteId) {
    if (err) {
      return failConnection(500, err, socket)
    }
    if (!noteId) {
      return failConnection(404, 'note id not found', socket)
    }

    if (isDuplicatedInSocketQueue(connectionSocketQueue, socket)) return

    // store noteId in this socket session
    socket.noteId = noteId

    // initialize user data
    // random color
    var color = randomcolor()
    // make sure color not duplicated or reach max random count
    if (notes[noteId]) {
      var randomcount = 0
      var maxrandomcount = 10
      var found = false
      do {
        Object.keys(notes[noteId].users).forEach(function (userId) {
          if (notes[noteId].users[userId].color === color) {
            found = true
          }
        })
        if (found) {
          color = randomcolor()
          randomcount++
        }
      } while (found && randomcount < maxrandomcount)
    }
    // create user data
    users[socket.id] = {
      id: socket.id,
      address: socket.handshake.headers['x-forwarded-for'] || socket.handshake.address,
      'user-agent': socket.handshake.headers['user-agent'],
      color: color,
      cursor: null,
      login: false,
      userid: null,
      name: null,
      idle: false,
      type: null
    }
    updateUserData(socket, users[socket.id])

    // start connection
    connectionSocketQueue.push(socket)
    startConnection(socket)
  })

  // received client refresh request
  socket.on('refresh', function () {
    emitRefresh(socket)
  })

  // received user status
  socket.on('user status', function (data) {
    var noteId = socket.noteId
    var user = users[socket.id]
    if (!noteId || !notes[noteId] || !user) return
    if (config.debug) { logger.info('SERVER received [' + noteId + '] user status from [' + socket.id + ']: ' + JSON.stringify(data)) }
    if (data) {
      user.idle = data.idle
      user.type = data.type
    }
    emitUserStatus(socket)
  })

  // received note permission change request
  socket.on('permission', function (permission) {
    // need login to do more actions
    if (socket.request.user && socket.request.user.logged_in) {
      var noteId = socket.noteId
      if (!noteId || !notes[noteId]) return
      var note = notes[noteId]
      // Only owner can change permission
      if (note.owner && note.owner === socket.request.user.id) {
        if (permission === 'freely' && !config.allowanonymous && !config.allowanonymousedits) return
        note.permission = permission
        models.Note.update({
          permission: permission
        }, {
          where: {
            id: noteId
          }
        }).then(function (count) {
          if (!count) {
            return
          }
          var out = {
            permission: permission
          }
          realtime.io.to(note.id).emit('permission', out)
          for (var i = 0, l = note.socks.length; i < l; i++) {
            var sock = note.socks[i]
            if (typeof sock !== 'undefined' && sock) {
              // check view permission
              if (!checkViewPermission(sock.request, note)) {
                sock.emit('info', {
                  code: 403
                })
                setTimeout(function () {
                  sock.disconnect(true)
                }, 0)
              }
            }
          }
        }).catch(function (err) {
          return logger.error('update note permission failed: ' + err)
        })
      }
    }
  })

  // delete a note
  socket.on('delete', function () {
    // need login to do more actions
    if (socket.request.user && socket.request.user.logged_in) {
      var noteId = socket.noteId
      if (!noteId || !notes[noteId]) return
      var note = notes[noteId]
      // Only owner can delete note
      if (note.owner && note.owner === socket.request.user.id) {
        models.Note.destroy({
          where: {
            id: noteId
          }
        }).then(function (count) {
          if (!count) return
          for (var i = 0, l = note.socks.length; i < l; i++) {
            var sock = note.socks[i]
            if (typeof sock !== 'undefined' && sock) {
              sock.emit('delete')
              setTimeout(function () {
                sock.disconnect(true)
              }, 0)
            }
          }
        }).catch(function (err) {
          return logger.error('delete note failed: ' + err)
        })
      }
    }
  })

  // reveiced when user logout or changed
  socket.on('user changed', function () {
    logger.info('user changed')
    var noteId = socket.noteId
    if (!noteId || !notes[noteId]) return
    var user = notes[noteId].users[socket.id]
    if (!user) return
    updateUserData(socket, user)
    emitOnlineUsers(socket)
  })

  // received sync of online users request
  socket.on('online users', function () {
    var noteId = socket.noteId
    if (!noteId || !notes[noteId]) return
    var users = []
    Object.keys(notes[noteId].users).forEach(function (key) {
      var user = notes[noteId].users[key]
      if (user) { users.push(buildUserOutData(user)) }
    })
    var out = {
      users: users
    }
    socket.emit('online users', out)
  })

  // check version
  socket.on('version', function () {
    socket.emit('version', {
      version: config.version,
      minimumCompatibleVersion: config.minimumCompatibleVersion
    })
  })

  // received cursor focus
  socket.on('cursor focus', function (data) {
    var noteId = socket.noteId
    var user = users[socket.id]
    if (!noteId || !notes[noteId] || !user) return
    user.cursor = data
    var out = buildUserOutData(user)
    socket.broadcast.to(noteId).emit('cursor focus', out)
  })

  // received cursor activity
  socket.on('cursor activity', function (data) {
    var noteId = socket.noteId
    var user = users[socket.id]
    if (!noteId || !notes[noteId] || !user) return
    user.cursor = data
    var out = buildUserOutData(user)
    socket.broadcast.to(noteId).emit('cursor activity', out)
  })

  // received cursor blur
  socket.on('cursor blur', function () {
    var noteId = socket.noteId
    var user = users[socket.id]
    if (!noteId || !notes[noteId] || !user) return
    user.cursor = null
    var out = {
      id: socket.id
    }
    socket.broadcast.to(noteId).emit('cursor blur', out)
  })

  // when a new client disconnect
  socket.on('disconnect', function () {
    if (isDuplicatedInSocketQueue(socket, disconnectSocketQueue)) return
    disconnectSocketQueue.push(socket)
    disconnect(socket)
  })
}

module.exports = realtime