Module: Innate::Cache::API
Overview
This is the API every Cache has to conform to.
The default behaviour is tailored for the Memory cache, override any behaviour as you need.
key
may be a String or Symbol value
is a Hash of serializable (as according to Marshal) objects
Every cache instance has to respond to:
::new()
#cache_setup(hostname, username, appname, cachename)
#cache_clear()
#cache_delete(*keys)
#cache_fetch(key, default = nil)
#cache_store(key, value, options = {})
We are prefixing cache_ to make the intent clear and implementation easier, as there may be existing behaviour associated with the non-prefixed version.
Also note that we create one instance per cache name-space.
Instance Method Summary collapse
-
#cache_clear ⇒ Object
Remove all key/value pairs from the cache.
-
#cache_delete(key, *keys) ⇒ Object Array nil
Remove the corresponding key/value pair for each key passed.
-
#cache_fetch(key, default = nil) ⇒ Object
Answer with the value associated with the
key
,nil
if not found or expired. -
#cache_setup(hostname, username, appname, cachename) ⇒ Object
Executed after #initialize and before any other method.
-
#cache_store(key, value, options = {}) {|key, value_hash| ... } ⇒ Object
Set
key
tovalue
.
Instance Method Details
#cache_clear ⇒ Object
Remove all key/value pairs from the cache. Should behave as if #delete had been called with all keys
as argument.
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# File 'lib/innate/cache/api.rb', line 44 def cache_clear clear end |
#cache_delete(key, *keys) ⇒ Object Array nil
Remove the corresponding key/value pair for each key passed. If removing is not an option it should set the corresponding value to nil.
If only one key was deleted, answer with the corresponding value. If multiple keys were deleted, answer with an Array containing the values.
NOTE: Due to differences in the underlying implementation in the
caches, some may not return the deleted value as it would mean
another lookup before deletion. This is the case for caches on
memcached or any database system.
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# File 'lib/innate/cache/api.rb', line 63 def cache_delete(key, *keys) if keys.empty? if value = yield(key) value[:value] end else [key, *keys].map{|element| cache_delete(element) } end end |
#cache_fetch(key, default = nil) ⇒ Object
Answer with the value associated with the key
, nil
if not found or expired.
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# File 'lib/innate/cache/api.rb', line 81 def cache_fetch(key, default = nil) value = default if entry = yield(key) if expires = entry[:expires] if expires > Time.now value = entry[:value] else cache_delete(key) end else value = entry[:value] end end return value end |
#cache_setup(hostname, username, appname, cachename) ⇒ Object
Executed after #initialize and before any other method.
Some parameters identifying the current process will be passed so caches that act in one global name-space can use them as a prefix.
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# File 'lib/innate/cache/api.rb', line 37 def cache_setup(hostname, username, appname, cachename) end |
#cache_store(key, value, options = {}) {|key, value_hash| ... } ⇒ Object
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# File 'lib/innate/cache/api.rb', line 116 def cache_store(key, value, = {}) ttl = [:ttl] value_hash = {:value => value} value_hash[:expires] = Time.now + ttl if ttl yield(key, value_hash) return value end |