-
Notifications
You must be signed in to change notification settings - Fork 0
/
session.go
723 lines (569 loc) · 15.4 KB
/
session.go
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
// Ninchat API connection library.
//
// https://ninchat.com/api
//
package ninchat
import (
"sort"
"sync"
)
const (
discoveryTimeout = second * 7
connectTimeout = second * 9
connectIterations = 2
maxBackoffDelay = second * 60
sessionCreateTimeout = second * 37
maxEventAckDelay = second * 7
maxEventAckWindow = 4096
)
var (
sessionEventAckWindow = jitterInt64(maxEventAckWindow, -0.25)
)
// Session hides the details of API connection management. It needs to be
// initialized by setting at least OnSessionEvent and OnEvent, and calling
// SetParams. After that the Open method is used to make a connection to the
// server. Finally, the Close method disconnects from the server.
type Session struct {
// OnSessionEvent is the session creation handler. It will be invoked with
// a "session_created" or an "error" event.
//
// If another "session_created" event is received, it means that the previous
// session was lost, and a new one was established automatically.
//
// If an "error" event is received, it means that a new session can't be
// established without intervention. The client code must call SetParams to
// supply new credentials, unless it decides to Close.
//
OnSessionEvent func(*Event)
// OnEvent is the handler for in-session events.
//
// "error" events received via this callback are not fatal.
//
OnEvent func(*Event)
// OnClose is an optional session closure handler. It will be invoked
// after a Close call has been fully processed. It won't be invoked if an
// "error" event is received via OnSessionEvent (unless SetParams is called
// again).
//
OnClose func()
// OnConnState is an optional connection state change monitor. It will be
// called with one of the following strings:
//
// - "connecting"
// - "connected"
// - "disconnected"
//
OnConnState func(state string)
// OnConnActive is an optional connection activity monitor. It will be
// called (approximately) when data is received on the underlying network
// connection.
OnConnActive func()
// OnLog is an optional message logger.
OnLog func(fragments ...interface{})
// Header fields to be added to HTTP requests. The keys must be in
// canonical format (see https://golang.org/pkg/net/http/#CanonicalHeaderKey).
Header map[string][]string
Address string
DisableLongPoll bool
forceLongPoll bool // only for testing
mutex sync.Mutex // guards all variables below
sessionParams map[string]interface{}
sessionId interface{}
latestConnState string
lastActionId int64
sendNotify chan struct{}
sendBuffer []*Action
numSent int
sendEventAck bool
receivedEventId int64
ackedEventId int64
closeNotify chan struct{}
closed bool
running bool
reconnect chan<- struct{}
test testSupport
}
// transport is an interface implemented by webSocketTransport and
// longPollTransport.
type transport func(s *Session, host string) (connWorked, gotOnline bool)
// SetParams sets initial action parameters. The initial action is
// "create_session" by default, or "resume_session" if the "session_id"
// parameter is set. If Open has already been called, this takes effect when a
// session is lost.
func (s *Session) SetParams(params map[string]interface{}) {
s.mutex.Lock()
defer s.mutex.Unlock()
if params["message_types"] == nil {
panic("message_types parameter not defined")
}
if x, found := params["session_id"]; x != nil {
s.sessionId = x
} else if found {
delete(params, "session_id")
}
s.sessionParams = params
if s.sendNotify != nil && !s.running {
// opened + stopped -> restart
s.running = true
go s.discover()
}
}
// Open creates a session on the server.
func (s *Session) Open() {
s.mutex.Lock()
defer s.mutex.Unlock()
if s.closed {
panic("session already closed")
}
if s.sendNotify != nil {
panic("session already initialized")
}
if s.OnSessionEvent == nil {
panic("onSessionEvent callback not defined")
}
if s.OnEvent == nil {
panic("onEvent callback not defined")
}
if s.sessionParams == nil {
panic("session parameters not defined")
}
if s.DisableLongPoll && !webSocketSupported {
panic("websocket not supported by browser")
}
s.sendNotify = make(chan struct{}, 1)
s.closeNotify = make(chan struct{}, 1)
s.running = true
go s.discover()
}
// Close the session on the server.
func (s *Session) Close() {
s.mutex.Lock()
defer s.mutex.Unlock()
if s.closed {
return
}
for _, action := range s.sendBuffer {
if action.OnReply != nil {
action.OnReply(nil)
}
}
s.sendBuffer = nil
s.numSent = 0
s.closed = true
s.running = false
go func() {
s.closeNotify <- struct{}{}
close(s.sendNotify)
}()
}
// Reconnect now, if reconnection process is currently waiting to retry. This
// gives a hint that network conditions have changed. It is safe to call this
// at any time.
func (s *Session) Reconnect() {
s.mutex.Lock()
defer s.mutex.Unlock()
if c := s.reconnect; c != nil {
s.reconnect = nil
close(c)
}
}
// Send an action.
//
// To send an action without an "action_id" parameter, specify it as nil.
// Otherwise an "action_id" is generated automatically.
//
// If "action_id" is used and the action's OnReply callback is set, it will be
// called when a reply event is received. If the Session object is closed
// before a reply is received, OnReply will be called with a nil argument.
//
// With specific actions that cause multiple reply events, the OnReply callback
// will be called for each event until the final event. Only the last event
// will have the LastReply member set.
//
func (s *Session) Send(action *Action) (err error) {
s.mutex.Lock()
defer s.mutex.Unlock()
if s.sendNotify == nil {
panic("session not initialized")
}
if s.closed {
panic("session already closed")
}
if len(action.Payload) == 0 {
action.Payload = nil
}
if x, found := action.Params["action_id"]; found && x == nil {
delete(action.Params, "action_id")
} else {
s.lastActionId++
action.id = s.lastActionId
action.Params["action_id"] = action.id
}
s.send(action)
return
}
// send buffers an action.
func (s *Session) send(action *Action) {
s.sendBuffer = append(s.sendBuffer, action)
go func() {
select {
case s.sendNotify <- struct{}{}:
default:
}
}()
return
}
// sendAck indicates that this is a good time to acknowledge received events.
func (s *Session) sendAck() {
s.sendEventAck = true
go func() {
select {
case s.sendNotify <- struct{}{}:
default:
}
}()
}
// discover runs an endpoint discovery loop.
func (s *Session) discover() {
s.mutex.Lock()
defer func() {
closed := s.closed
s.mutex.Unlock()
if closed && s.OnClose != nil {
s.OnClose()
}
}()
s.log("starting")
defer s.log("stopped")
defer s.connState("disconnected")
var backoff backoff
for s.running {
s.connState("connecting")
url := "https://" + getAddress(s.Address) + endpointPath
request, err := newGetRequest(url, s.Header)
if err != nil {
panic(err)
}
s.mutex.Unlock()
select {
case response := <-getResponseChannel(request, jitterDuration(discoveryTimeout, 0.1)):
s.mutex.Lock()
var hosts []string
err := response.err
if err == nil {
var endpoint map[string]interface{}
if err = jsonUnmarshalObject(response.data, &endpoint); err == nil {
hosts, err = getEndpointHosts(endpoint)
}
}
if err == nil {
s.log("endpoint discovered")
if webSocketSupported && !s.forceLongPoll {
if s.connect(webSocketTransport, hosts, &backoff) {
continue
}
}
if !s.DisableLongPoll {
s.connect(longPollTransport, hosts, &backoff)
}
} else {
s.log("endpoint discovery:", err)
}
case <-s.closeNotify:
s.mutex.Lock()
return
}
if !s.backOff(&backoff) {
return
}
}
}
// connect tries to connect to each host a few times using the given transport
// implementation.
func (s *Session) connect(transport transport, hosts []string, backoff *backoff) (transportWorked bool) {
for trial := 0; trial < connectIterations; trial++ {
for _, host := range hosts {
s.connState("connecting")
for i, c := range s.Address {
if c == '/' {
host += s.Address[i:]
break
}
}
//gopherjs:blocking
connWorked, gotOnline := transport(s, host)
if connWorked {
transportWorked = true
}
if gotOnline {
backoff.success()
return
}
if !s.running {
return
}
if !s.backOff(backoff) {
return
}
}
}
return
}
// backOff sleeps for a time. False is returned if session was closed while
// sleeping.
func (s *Session) backOff(b *backoff) bool {
delay := b.failure(maxBackoffDelay)
if delay == 0 {
return true
}
s.connState("disconnected")
s.log("sleeping")
reconnect := make(chan struct{}, 1)
s.reconnect = reconnect
s.mutex.Unlock()
defer func() {
s.mutex.Lock()
s.reconnect = nil
}()
timer := newTimer(delay)
defer timer.Stop()
select {
case <-timer.C:
return true
case <-reconnect:
return true
case <-s.closeNotify:
return false
}
}
// canLogin checks whether the makeCreateSessionAction method would make an
// action that has any chance of creating a session for an existing user.
// The answer is no if the action could succeed, but would create a new
// user.
func (s *Session) canLogin() bool {
if x, found := s.sessionParams["user_existing"]; found && x != nil {
if value, ok := x.(bool); ok && !value {
return false
}
}
if s.sessionParams["access_key"] != nil {
return true
}
if s.sessionParams["user_id"] != nil {
return s.sessionParams["user_auth"] != nil || s.sessionParams["master_sign"] != nil
}
return s.sessionParams["identity_type"] != nil && s.sessionParams["identity_name"] != nil && s.sessionParams["identity_auth"] != nil
}
// makeCreateSessionAction makes a create_session action header.
func (s *Session) makeCreateSessionAction() (params map[string]interface{}) {
params = map[string]interface{}{
"action": "create_session",
}
if userId := s.sessionParams["user_id"]; userId == nil {
// Client code is responsible for specifying correct parameters.
for key, value := range s.sessionParams {
params[key] = value
}
} else {
// This might be automatic session recreation, try to be smart.
params["user_existing"] = true
if userAuth := s.sessionParams["user_auth"]; userAuth != nil {
params["user_id"] = userId
params["user_auth"] = userAuth
} else if masterSign := s.sessionParams["master_sign"]; masterSign != nil {
params["user_id"] = userId
params["master_sign"] = masterSign
} else if identityType := s.sessionParams["identity_type"]; identityType != nil {
params["identity_type"] = identityType
params["identity_name"] = s.sessionParams["identity_name"]
params["identity_auth"] = s.sessionParams["identity_auth"]
} else {
// Fallback: let the server decide. (But still make sure that we
// won't be creating a new user by accident.)
params["user_id"] = userId
}
for key, value := range s.sessionParams {
switch key {
case "user_id", "user_auth", "user_existing", "identity_type", "identity_name", "identity_auth", "access_key", "master_sign":
// skipped
default:
params[key] = value
}
}
}
return
}
// makeResumeSessionAction makes a resume_session action header for
// initializing new connections, or polling and acknowledging events.
func (s *Session) makeResumeSessionAction(session bool) (params map[string]interface{}) {
params = map[string]interface{}{
"action": "resume_session",
"event_id": s.receivedEventId,
}
if session {
params["session_id"] = s.sessionId
}
s.sendEventAck = false
s.ackedEventId = s.receivedEventId
return
}
// handleSessionEvent establishes a session or fails.
func (s *Session) handleSessionEvent(params map[string]interface{}) (ok bool) {
event := &Event{
Params: params,
}
quit := false
if event.String() == "error" {
s.sessionId = nil
quit = true
switch errorType, _ := event.Str("error_type"); errorType {
case "internal":
// keep trying
default:
s.running = false
}
}
s.deliverSessionEvent(event)
if quit {
return
}
delete(s.sessionParams, "user_attrs")
delete(s.sessionParams, "user_settings")
delete(s.sessionParams, "identity_attrs")
delete(s.sessionParams, "access_key")
delete(s.sessionParams, "master_sign")
s.sessionParams["user_existing"] = true
s.sessionParams["user_id"] = event.Params["user_id"]
if x := event.Params["user_auth"]; x != nil {
s.sessionParams["user_auth"] = x
}
for _, param := range []string{"identity_type", "identity_name", "identity_auth"} {
if newValue := s.sessionParams[param+"_new"]; newValue != nil {
delete(s.sessionParams, param+"_new")
s.sessionParams[param] = newValue
}
}
s.sessionId = event.Params["session_id"]
if len(s.sendBuffer) == 0 {
s.lastActionId = 0
}
s.sendEventAck = false
s.receivedEventId, _ = event.Int64("event_id")
s.ackedEventId = 0
s.log("session created")
ok = true
return
}
// handleEvent parses the event header partially, does whatever is necessary,
// and usually passes the event to client code.
func (s *Session) handleEvent(event *Event) (actionId int64, sessionLost, needsAck, ok bool) {
if eventId, _ := event.Int64("event_id"); eventId > 0 {
s.receivedEventId = eventId
if !s.sendEventAck {
if s.receivedEventId-s.ackedEventId >= sessionEventAckWindow {
s.sendAck()
} else {
needsAck = true
}
}
}
actionId, _ = event.Int64("action_id")
if actionId > 0 {
i := sort.Search(s.numSent, func(i int) bool {
action := s.sendBuffer[i]
return action.id >= actionId
})
if i < s.numSent {
if action := s.sendBuffer[i]; action.id == actionId {
event.initLastReply(action)
if action.OnReply != nil {
s.deliverReply(action, event)
}
if event.LastReply {
s.sendBuffer = append(s.sendBuffer[:i], s.sendBuffer[i+1:]...)
s.numSent--
}
}
}
}
if event.String() == "user_deleted" {
s.sessionId = nil
s.running = false
s.deliverSessionEvent(event)
sessionLost = true
return
}
errorType, errorReason, userAuthLost, sessionLost, err := event.getError()
if err != nil {
s.log("event:", err)
if userAuthLost {
delete(s.sessionParams, "user_auth")
}
if sessionLost {
s.sessionId = nil
if !s.canLogin() {
s.running = false
s.deliverSessionEvent(event)
}
}
return
}
if errorType == "deprecated" {
s.log("deprecated:", errorReason)
}
s.deliverEvent(event)
ok = true
return
}
func (s *Session) deliverSessionEvent(event *Event) {
s.mutex.Unlock()
defer s.mutex.Lock()
s.OnSessionEvent(event)
}
func (s *Session) deliverEvent(event *Event) {
s.mutex.Unlock()
defer s.mutex.Lock()
s.OnEvent(event)
}
func (s *Session) deliverReply(action *Action, event *Event) {
s.mutex.Unlock()
defer s.mutex.Lock()
action.OnReply(event)
}
// connState passes an enumeration value to the client code.
func (s *Session) connState(state string) {
if s.latestConnState == state {
return
}
s.latestConnState = state
if s.OnConnState == nil {
return
}
s.mutex.Unlock()
defer s.mutex.Lock()
s.OnConnState(state)
}
// connActive pokes the client code.
func (s *Session) connActive() {
if s.OnConnActive == nil {
return
}
s.mutex.Unlock()
defer s.mutex.Lock()
s.OnConnActive()
}
// log passes a message to the client code.
func (s *Session) log(tokens ...interface{}) {
if s.OnLog == nil {
return
}
s.mutex.Unlock()
defer s.mutex.Lock()
s.OnLog(tokens...)
}
// nonunlockingLog can be called in contexts which do not hold Session.mutex.
func (s *Session) nonunlockingLog(tokens ...interface{}) {
if s.OnLog != nil {
s.OnLog(tokens...)
}
}