Class: Readthis::Cache

Inherits:
Object
  • Object
show all
Defined in:
lib/readthis/cache.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(url, options = {}) ⇒ Cache

Creates a new Readthis::Cache object with the given redis URL. The URL is parsed by the redis client directly.

Readthis::Cache.new('redis://localhost:6379/0', namespace: 'cache')



26
27
28
29
30
31
32
33
 
# File 'lib/readthis/cache.rb', line 26

def initialize(url, options = {})
  @expires_in = options.fetch(:expires_in, nil)
  @namespace  = options.fetch(:namespace, nil)

  @pool = ConnectionPool.new(pool_options(options)) do
    Redis.new(url: url)
  end
end

Instance Attribute Details

#expires_in ⇒ Object (readonly)

Returns the value of attribute expires_in.



8
9
10
 
# File 'lib/readthis/cache.rb', line 8

def expires_in
  @expires_in
end

#namespace ⇒ Object (readonly)

Returns the value of attribute namespace.



8
9
10
 
# File 'lib/readthis/cache.rb', line 8

def namespace
  @namespace
end

#pool ⇒ Object (readonly)

Returns the value of attribute pool.



8
9
10
 
# File 'lib/readthis/cache.rb', line 8

def pool
  @pool
end

Class Method Details

.notifications ⇒ Object

Provide a class level lookup of the proper notifications module. Instrumention is expected to occur within applications that have ActiveSupport::Notifications available, but needs to work even when it isn’t.



14
15
16
17
18
19
20
 
# File 'lib/readthis/cache.rb', line 14

def self.notifications
  if Object.const_defined?('ActiveSupport::Notifications')
    ActiveSupport::Notifications
  else
    Readthis::Notifications
  end
end

Instance Method Details

#clear ⇒ Object 



144
145
146
147
148
149
150
 
# File 'lib/readthis/cache.rb', line 144

def clear
  instrument(:clear, '*') do
    with do |store|
      store.flushdb
    end
  end
end

#decrement(key, options = {}) ⇒ Object 



85
86
87
88
89
90
91
 
# File 'lib/readthis/cache.rb', line 85

def decrement(key, options = {})
  instrument(:decrement, key) do
    with do |store|
      store.decr(namespaced_key(key, merged_options(options)))
    end
  end
end

#delete(key, options = {}) ⇒ Object 



58
59
60
61
62
63
64
 
# File 'lib/readthis/cache.rb', line 58

def delete(key, options = {})
  instrument(:delete, key) do
    with do |store|
      store.del(namespaced_key(key, merged_options(options)))
    end
  end
end

#exist?(key, options = {}) ⇒ Boolean

Returns:

  • (Boolean) 


136
137
138
139
140
141
142
 
# File 'lib/readthis/cache.rb', line 136

def exist?(key, options = {})
  instrument(:exist?, key) do
    with do |store|
      store.exists(namespaced_key(key, merged_options(options)))
    end
  end
end

#fetch(key, options = {}) ⇒ Object 



66
67
68
69
70
71
72
73
74
75
 
# File 'lib/readthis/cache.rb', line 66

def fetch(key, options = {})
  value = read(key, options) unless options[:force]

  if value.nil? && block_given?
    value = yield(key)
    write(key, value, options)
  end

  value
end

#fetch_multi(*keys) ⇒ Object

Fetches multiple keys from the cache using a single call to the server and filling in any cache misses. All read and write operations are executed atomically.

cache.fetch_multi('alpha', 'beta') do |key|
  "#{key}-was-missing"
end



115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
 
# File 'lib/readthis/cache.rb', line 115

def fetch_multi(*keys)
  results = read_multi(*keys)
  options = merged_options(extract_options!(keys))

  instrument(:fetch_multi, keys) do
    with do |store|
      store.pipelined do
        results.each do |key, value|
          if value.nil?
            value = yield key
            write(key, value, options)
            results[key] = value
          end
        end
      end
    end

    results
  end
end

#increment(key, options = {}) ⇒ Object 



77
78
79
80
81
82
83
 
# File 'lib/readthis/cache.rb', line 77

def increment(key, options = {})
  instrument(:incremenet, key) do
    with do |store|
      store.incr(namespaced_key(key, merged_options(options)))
    end
  end
end

#read(key, options = {}) ⇒ Object 



35
36
37
38
39
40
41
 
# File 'lib/readthis/cache.rb', line 35

def read(key, options = {})
  instrument(:read, key) do
    with do |store|
      store.get(namespaced_key(key, merged_options(options)))
    end
  end
end

#read_multi(*keys) ⇒ Object 



93
94
95
96
97
98
99
100
101
102
103
104
105
106
 
# File 'lib/readthis/cache.rb', line 93

def read_multi(*keys)
  options = merged_options(extract_options!(keys))
  results = []

  instrument(:read_multi, keys) do
    with do |store|
      results = store.pipelined do
        keys.each { |key| store.get(namespaced_key(key, options)) }
      end
    end

    keys.zip(results).to_h
  end
end

#write(key, value, options = {}) ⇒ Object 



43
44
45
46
47
48
49
50
51
52
53
54
55
56
 
# File 'lib/readthis/cache.rb', line 43

def write(key, value, options = {})
  options    = merged_options(options)
  namespaced = namespaced_key(key, options)

  instrument(:write, key) do
    with do |store|
      if expiration = options[:expires_in]
        store.setex(namespaced, expiration, value)
      else
        store.set(namespaced, value)
      end
    end
  end
end