Class: PrefixedCacheStore

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/prefixed_cache_store.rb

Overview

A caching store that will expire only the keys saved through it, by using a common prefix for the namespace and the version number that can be ratched up to “unlink” all the related keys. It assumes that the keys are being evicted automatically if they do not get used often.

Constant Summary collapse

VERSION = 
'0.2.2'
RETAIN_PREFIX_FOR_SECONDS = 
10

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(store, prefix = 'pfx') ⇒ PrefixedCacheStore

Returns a new instance of PrefixedCacheStore.



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# File 'lib/prefixed_cache_store.rb', line 22

def initialize(store, prefix = 'pfx')
  @store = store
  @prefix = prefix
end

Instance Attribute Details

#prefix ⇒ Object (readonly)

Returns the value of attribute prefix.



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# File 'lib/prefixed_cache_store.rb', line 14

def prefix
  @prefix
end

#store ⇒ Object (readonly)

Returns the value of attribute store.



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# File 'lib/prefixed_cache_store.rb', line 14

def store
  @store
end

Instance Method Details

#clear(options = nil) ⇒ Object

Bump the version prefix making all keys obsolete.



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# File 'lib/prefixed_cache_store.rb', line 94

def clear(options=nil)
  bump_version! # First bump the version
  @last_prefix = nil # Then make sure the cached version number will not be used
  get_and_set_current_version
end

#current_version_number ⇒ Object

Returns the current version that has been set for this store



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# File 'lib/prefixed_cache_store.rb', line 101

def current_version_number
  get_and_set_current_version
end

#decrement(name, amount = 1, options = nil) ⇒ Object

Decrement a cached value.



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# File 'lib/prefixed_cache_store.rb', line 85

def decrement(name, amount = 1, options=nil)
  if @store.method(:decrement).parameters.length > 2
    @store.decrement(prefix_key(name), amount, options)
  else
    @store.increment(prefix_key(name), amount) # Toss the options
  end
end

#delete(name, options = nil) ⇒ Object 



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# File 'lib/prefixed_cache_store.rb', line 59

def delete(name, options=nil)
  @store.delete(prefix_key(name), options)
end

#exist?(name, options = nil) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/prefixed_cache_store.rb', line 55

def exist?(name, options=nil)
  @store.exist?(prefix_key(name), options)
end

#fetch(name, options = nil) ⇒ Object 



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# File 'lib/prefixed_cache_store.rb', line 27

def fetch(name, options=nil)
  if block_given?
    @store.fetch(prefix_key(name), options) { yield }
  else
    @store.fetch(prefix_key(name), options)
  end
end

#fetch_multi(*names) ⇒ Object 



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# File 'lib/prefixed_cache_store.rb', line 35

def fetch_multi(*names)
  if !@store.respond_to?(:fetch_multi)
    raise NoMethodError, "#{@store.inspect} does not support fetch_multi()"
  end
  
  options = names.extract_options!
  prefixed_keys = names.map{|e| prefix_key(e) }
  @store.fetch_multi(*prefixed_keys, options) do | prefixed_key |
    yield(unprefix_key(prefixed_key))
  end
end

#increment(name, amount = 1, options = nil) ⇒ Object

Increment a cached value.



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# File 'lib/prefixed_cache_store.rb', line 76

def increment(name, amount = 1, options=nil)
  if @store.method(:increment).parameters.length > 2
    @store.increment(prefix_key(name), amount, options)
  else
    @store.increment(prefix_key(name), amount) # Toss the options
  end
end

#read(name, options = nil) ⇒ Object 



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# File 'lib/prefixed_cache_store.rb', line 47

def read(name, options=nil)
  @store.read(prefix_key(name), options)
end

#read_multi(*names) ⇒ Object

Reads multiple keys from the cache using a single call to the servers for all keys. Keys must be Strings.



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# File 'lib/prefixed_cache_store.rb', line 65

def read_multi(*names)
  names.extract_options!
  prefixed_names = names.map{|e| prefix_key(e) }
  result = @store.read_multi(*prefixed_names)
  # Unprefix the keys received
  result.inject({}) do |memo, (prefixed_key, value)|
    memo.merge(unprefix_key(prefixed_key) => value)
  end
end

#write(name, value, options = nil) ⇒ Object 



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# File 'lib/prefixed_cache_store.rb', line 51

def write(name, value, options=nil)
  @store.write(prefix_key(name), value, options)
end