Module: ActionController::Caching::Fragments
- Included in:
- ActionController::Caching
- Defined in:
- lib/action_controller/caching/fragments.rb
Overview
Fragment caching is used for caching various blocks within views without caching the entire action as a whole. This is useful when certain elements of an action change frequently or depend on complicated state while other parts rarely change or can be shared amongst multiple parties. The caching is done using the cache
helper available in the Action View. See ActionView::Helpers::CacheHelper for more information.
While it’s strongly recommended that you use key-based cache expiration (see links in CacheHelper for more information), it is also possible to manually expire caches. For example:
expire_fragment('name_of_cache')
Instance Method Summary collapse
-
#expire_fragment(key, options = nil) ⇒ Object
Removes fragments from the cache.
-
#fragment_cache_key(key) ⇒ Object
Given a key (as described in
expire_fragment
), returns a key suitable for use in reading, writing, or expiring a cached fragment. -
#fragment_exist?(key, options = nil) ⇒ Boolean
Check if a cached fragment from the location signified by
key
exists (seeexpire_fragment
for acceptable formats). -
#instrument_fragment_cache(name, key) ⇒ Object
:nodoc:.
-
#read_fragment(key, options = nil) ⇒ Object
Reads a cached fragment from the location signified by
key
(seeexpire_fragment
for acceptable formats). -
#write_fragment(key, content, options = nil) ⇒ Object
Writes
content
to the location signified bykey
(seeexpire_fragment
for acceptable formats).
Instance Method Details
#expire_fragment(key, options = nil) ⇒ Object
Removes fragments from the cache.
key
can take one of three forms:
-
String - This would normally take the form of a path, like
pages/45/notes
. -
Hash - Treated as an implicit call to
url_for
, like{ controller: 'pages', action: 'notes', id: 45}
-
Regexp - Will remove any fragment that matches, so
%r{pages/\d*/notes}
might remove all notes. Make sure you don’t use anchors in the regex (^
or$
) because the actual filename matched looks like./cache/filename/path.cache
. Note: Regexp expiration is only supported on caches that can iterate over all keys (unlike memcached).
options
is passed through to the cache store’s delete
method (or delete_matched
, for Regexp keys).
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# File 'lib/action_controller/caching/fragments.rb', line 79 def expire_fragment(key, = nil) return unless cache_configured? key = fragment_cache_key(key) unless key.is_a?(Regexp) instrument_fragment_cache :expire_fragment, key do if key.is_a?(Regexp) cache_store.delete_matched(key, ) else cache_store.delete(key, ) end end end |
#fragment_cache_key(key) ⇒ Object
Given a key (as described in expire_fragment
), returns a key suitable for use in reading, writing, or expiring a cached fragment. All keys are prefixed with views/
and uses ActiveSupport::Cache.expand_cache_key for the expansion.
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# File 'lib/action_controller/caching/fragments.rb', line 21 def fragment_cache_key(key) ActiveSupport::Cache.(key.is_a?(Hash) ? url_for(key).split("://").last : key, :views) end |
#fragment_exist?(key, options = nil) ⇒ Boolean
Check if a cached fragment from the location signified by key
exists (see expire_fragment
for acceptable formats).
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# File 'lib/action_controller/caching/fragments.rb', line 52 def fragment_exist?(key, = nil) return unless cache_configured? key = fragment_cache_key(key) instrument_fragment_cache :exist_fragment?, key do cache_store.exist?(key, ) end end |
#instrument_fragment_cache(name, key) ⇒ Object
:nodoc:
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# File 'lib/action_controller/caching/fragments.rb', line 92 def instrument_fragment_cache(name, key) # :nodoc: ActiveSupport::Notifications.instrument("#{name}.action_controller", :key => key){ yield } end |
#read_fragment(key, options = nil) ⇒ Object
Reads a cached fragment from the location signified by key
(see expire_fragment
for acceptable formats).
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# File 'lib/action_controller/caching/fragments.rb', line 40 def read_fragment(key, = nil) return unless cache_configured? key = fragment_cache_key(key) instrument_fragment_cache :read_fragment, key do result = cache_store.read(key, ) result.respond_to?(:html_safe) ? result.html_safe : result end end |
#write_fragment(key, content, options = nil) ⇒ Object
Writes content
to the location signified by key
(see expire_fragment
for acceptable formats).
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# File 'lib/action_controller/caching/fragments.rb', line 27 def write_fragment(key, content, = nil) return content unless cache_configured? key = fragment_cache_key(key) instrument_fragment_cache :write_fragment, key do content = content.to_str cache_store.write(key, content, ) end content end |