Module: IdentityCache

Extended by:
CacheHash
Defined in:
lib/identity_cache.rb,
lib/identity_cache/version.rb,
lib/identity_cache/query_api.rb,
lib/identity_cache/cache_hash.rb,
lib/identity_cache/cache_fetcher.rb,
lib/identity_cache/fallback_fetcher.rb,
lib/identity_cache/configuration_dsl.rb,
lib/identity_cache/belongs_to_caching.rb,
lib/identity_cache/cache_invalidation.rb,
lib/identity_cache/cache_key_generation.rb,
lib/identity_cache/memoized_cache_proxy.rb,
lib/identity_cache/parent_model_expiration.rb

Defined Under Namespace

Modules: BelongsToCaching, CacheHash, CacheInvalidation, CacheKeyGeneration, ConfigurationDSL, ParentModelExpiration, QueryAPI Classes: AlreadyIncludedError, AssociationError, CacheFetcher, DerivedModelError, FallbackFetcher, InverseAssociationError, MemoizedCacheProxy, UnsupportedAssociationError, UnsupportedScopeError

Constant Summary collapse

CACHED_NIL = 
:idc_cached_nil
BATCH_SIZE = 
1000
DELETED = 
:idc_cached_deleted
DELETED_TTL = 
1000
VERSION = 
"0.3.2"
CACHE_VERSION = 
6

Class Attribute Summary collapse

Class Method Summary collapse

Methods included from CacheHash

memcache_hash

Class Attribute Details

.logger ⇒ Object 



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# File 'lib/identity_cache.rb', line 91

def logger
  @logger || Rails.logger
end

.readonly ⇒ Object

Returns the value of attribute readonly.



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# File 'lib/identity_cache.rb', line 37

def readonly
  @readonly
end

Class Method Details

.cache ⇒ Object 



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# File 'lib/identity_cache.rb', line 87

def cache
  @cache ||= MemoizedCacheProxy.new
end

.cache_backend=(cache_adaptor) ⇒ Object

Sets the cache adaptor IdentityCache will be using

Parameters

cache_adaptor - A ActiveSupport::Cache::Store



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# File 'lib/identity_cache.rb', line 79

def cache_backend=(cache_adaptor)
  if defined?(@cache)
    cache.cache_backend = cache_adaptor
  else
    @cache = MemoizedCacheProxy.new(cache_adaptor)
  end
end

.fetch(key) ⇒ Object

Cache retrieval and miss resolver primitive; given a key it will try to retrieve the associated value from the cache otherwise it will return the value of the execution of the block.

Parameters

key A cache key string



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# File 'lib/identity_cache.rb', line 111

def fetch(key)
  if should_use_cache?
    unmap_cached_nil_for(cache.fetch(key) { map_cached_nil_for yield })
  else
    yield
  end
end

.fetch_multi(*keys) ⇒ Object

Same as fetch, except that it will try a collection of keys, using the multiget operation of the cache adaptor.

Parameters

keys A collection or array of key strings



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# File 'lib/identity_cache.rb', line 132

def fetch_multi(*keys)
  keys.flatten!(1)
  return {} if keys.size == 0

  result = if should_use_cache?
    fetch_in_batches(keys.uniq) do |missed_keys|
      results = yield missed_keys
      results.map {|e| map_cached_nil_for e }
    end
  else
    results = yield keys
    Hash[keys.zip(results)]
  end

  result.each do |key, value|
    result[key] = unmap_cached_nil_for(value)
  end

  result
end

.included(base) ⇒ Object

:nodoc:

Raises:



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# File 'lib/identity_cache.rb', line 62

def included(base) #:nodoc:
  raise AlreadyIncludedError if base.include?(IdentityCache::ConfigurationDSL)

  base.send(:include, ArTransactionChanges) unless base.include?(ArTransactionChanges)
  base.send(:include, IdentityCache::BelongsToCaching)
  base.send(:include, IdentityCache::CacheKeyGeneration)
  base.send(:include, IdentityCache::ConfigurationDSL)
  base.send(:include, IdentityCache::QueryAPI)
  base.send(:include, IdentityCache::CacheInvalidation)
end

.map_cached_nil_for(value) ⇒ Object 



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# File 'lib/identity_cache.rb', line 119

def map_cached_nil_for(value)
  value.nil? ? IdentityCache::CACHED_NIL : value
end

.should_fill_cache? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/identity_cache.rb', line 95

def should_fill_cache? # :nodoc:
  !readonly
end

.should_use_cache? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/identity_cache.rb', line 99

def should_use_cache? # :nodoc:
  pool = ActiveRecord::Base.connection_pool
  !pool.active_connection? || pool.connection.open_transactions == 0
end

.unmap_cached_nil_for(value) ⇒ Object 



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# File 'lib/identity_cache.rb', line 123

def unmap_cached_nil_for(value)
  value == IdentityCache::CACHED_NIL ? nil : value
end

.with_fetch_read_only_records(value = true) ⇒ Object 



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# File 'lib/identity_cache.rb', line 170

def with_fetch_read_only_records(value = true)
  old_value = self.fetch_read_only_records
  self.fetch_read_only_records = value
  yield
ensure
  self.fetch_read_only_records = old_value
end

.with_fetch_returns_relation(value = true) ⇒ Object 



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# File 'lib/identity_cache.rb', line 153

def with_fetch_returns_relation(value = true)
  previous_value = self.fetch_returns_relation
  self.fetch_returns_relation = value
  yield
ensure
  self.fetch_returns_relation = previous_value
end

.with_never_set_inverse_association(value = true) ⇒ Object 



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# File 'lib/identity_cache.rb', line 161

def with_never_set_inverse_association(value = true)
  old_value = self.never_set_inverse_association
  self.never_set_inverse_association = value
  yield
ensure
  self.never_set_inverse_association = old_value
end