Class: TimedCache

Inherits:
Object show all
Defined in:
lib/tins/timed_cache.rb

Defined Under Namespace

Classes: Value

Instance Method Summary collapse

Constructor Details

#initialize(name, ttl: 60, jitter: 1..5, &block) ⇒ TimedCache

Returns a new instance of TimedCache.



12
13
14
15
16
17
18
19
 
# File 'lib/tins/timed_cache.rb', line 12

def initialize(name, ttl: 60, jitter: 1..5, &block)
  @name   = name
  @ttl    = ttl
  @jitter = jitter
  block or raise ArgumentError, 'block is required'
  @block = block
  @redis = Redis.new
end

Instance Method Details

#namespaced(key) ⇒ Object 



21
22
23
 
# File 'lib/tins/timed_cache.rb', line 21

def namespaced(key)
  "timed_cache:#{key}"
end

#new_value(now) ⇒ Object 



44
45
46
 
# File 'lib/tins/timed_cache.rb', line 44

def new_value(now)
  Value.new(@block.(), now.to_i)
end

#stored_value ⇒ Object 



48
49
50
 
# File 'lib/tins/timed_cache.rb', line 48

def stored_value
  @redis.get(namespaced(@name)).full? { |s| ::JSON.parse(s, create_additions: true) rescue nil }
end

#value ⇒ Object 



25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
 
# File 'lib/tins/timed_cache.rb', line 25

def value
  now = Time.now
  if stored = stored_value
    if (now - @ttl).to_i >= stored.timestamp
      Thread.new {
        sleep @jitter
        if stored_value.timestamp <= stored.timestamp
          @redis.set namespaced(@name), new_value(now).to_json
        end
      }
    end
    stored.value
  else
    nv = new_value(now)
    @redis.set namespaced(@name), nv.to_json
    nv.value
  end
end