appbase.utils.cache source code

1 module appbase.utils.cache;
2 
3 import std.conv;
4 import std.datetime;
5 import std.variant;
6 
7 __gshared private CacheValue[string] _cacheContainer;
8 
9 private class CacheValue
10 {
11     DateTime time;
12     int expireMinutes;
13     Variant value;
14 
15     this(Variant value, int expireMinutes)
16     {
17         time = cast(DateTime)Clock.currTime();
18         this.expireMinutes = expireMinutes;
19         this.value = value;
20     }
21 }
22 
23 class Cache
24 {
25     static void set(T)(string key, T value, int expireMinutes = 30)
26     {
27         _cacheContainer[key] = new CacheValue(Variant(value), expireMinutes);
28     }
29 
30     static T get(T)(string key, T defaultValue)
31     {
32         CacheValue item;
33 
34         if (key !in _cacheContainer)
35         {
36             return defaultValue;
37         }
38 
39         synchronized (Cache.classinfo)
40         {
41             if (key !in _cacheContainer)
42             {
43                 return defaultValue;
44             }
45 
46             item = _cacheContainer.get(key, null);
47 
48             if (item is null)
49             {
50                 return defaultValue;
51             }
52 
53             DateTime now = cast(DateTime)Clock.currTime();
54             if ((now - item.time).total!"minutes" > item.expireMinutes)
55             {
56                 _cacheContainer.remove(key);
57 
58                 return defaultValue;
59             }
60         }
61 
62         if (!item.value.convertsTo!T)
63         {
64             return defaultValue;
65         }
66 
67         return item.value.get!T;
68     }
69 
70     static void remove(string key)
71 	{
72 		if (key in _cacheContainer)
73         {
74             synchronized (Cache.classinfo)
75             {
76                 if (key in _cacheContainer)
77                 {
78                     _cacheContainer.remove(key);
79                 }
80             }
81 		}
82 	}
83 }