OLD | NEW |
1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 library microlytics.channels; | 5 library microlytics.channels; |
6 | 6 |
7 import 'dart:async'; | 7 import 'dart:async'; |
8 | 8 |
9 const String ANALYTICS_URL = "https://ssl.google-analytics.com/collect"; | 9 const String ANALYTICS_URL = "https://ssl.google-analytics.com/collect"; |
10 | 10 |
11 abstract class Channel { | 11 abstract class Channel { |
12 void sendData(String data); | 12 void sendData(String data); |
13 void shutdown() {} | 13 void shutdown() {} |
14 } | 14 } |
15 | 15 |
16 /// [Channel] that implements a leaky bucket | 16 /// [Channel] that implements a leaky bucket |
17 /// algorithm to provide rate limiting. | 17 /// algorithm to provide rate limiting. |
18 /// See [http://en.wikipedia.org/wiki/Leaky_bucket]. | 18 /// See [http://en.wikipedia.org/wiki/Leaky_bucket]. |
19 class RateLimitingBufferedChannel extends Channel { | 19 class RateLimitingBufferedChannel extends Channel { |
20 final List<String> _buffer = <String>[]; | 20 final List<String> _buffer = <String>[]; |
21 final Channel _innerChannel; | 21 final Channel _innerChannel; |
22 final int _bufferSizeLimit; | 22 final int _bufferSizeLimit; |
23 Timer _timer; | 23 Timer _timer; |
24 | 24 |
25 RateLimitingBufferedChannel( | 25 RateLimitingBufferedChannel(this._innerChannel, |
26 this._innerChannel, | 26 {int bufferSizeLimit: 10, double packetsPerSecond: 1.0}) |
27 {int bufferSizeLimit: 10, | |
28 double packetsPerSecond: 1.0}) | |
29 : this._bufferSizeLimit = bufferSizeLimit { | 27 : this._bufferSizeLimit = bufferSizeLimit { |
30 if (!(packetsPerSecond > 0)) { | 28 if (!(packetsPerSecond > 0)) { |
31 throw new ArgumentError("packetsPerSecond must be larger than zero."); | 29 throw new ArgumentError("packetsPerSecond must be larger than zero."); |
32 } | 30 } |
33 | 31 |
34 int transmitDelay = (1000 / packetsPerSecond).floor(); | 32 int transmitDelay = (1000 / packetsPerSecond).floor(); |
35 _timer = new Timer.periodic( | 33 _timer = new Timer.periodic( |
36 new Duration(milliseconds: transmitDelay), _onTimerTick); | 34 new Duration(milliseconds: transmitDelay), _onTimerTick); |
37 } | 35 } |
38 | 36 |
39 void _onTimerTick(_) { | 37 void _onTimerTick(_) { |
40 if (_buffer.length > 0) { | 38 if (_buffer.length > 0) { |
41 String item = _buffer.removeLast(); | 39 String item = _buffer.removeLast(); |
42 _innerChannel.sendData(item); | 40 _innerChannel.sendData(item); |
43 } | 41 } |
44 } | 42 } |
45 | 43 |
46 void sendData(String data) { | 44 void sendData(String data) { |
47 if (_buffer.length >= _bufferSizeLimit) return; | 45 if (_buffer.length >= _bufferSizeLimit) return; |
48 _buffer.add(data); | 46 _buffer.add(data); |
49 } | 47 } |
50 | 48 |
51 void shutdown() { | 49 void shutdown() { |
52 _timer.cancel(); | 50 _timer.cancel(); |
53 _innerChannel.shutdown(); | 51 _innerChannel.shutdown(); |
54 } | 52 } |
55 } | 53 } |
OLD | NEW |