Module: AbstractController::Caching::Fragments
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Modules:
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Extension / Inclusion / Inheritance Descendants | |
Included In:
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Class Chain:
self,
::ActiveSupport::Concern
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Defined in: | actionpack/lib/abstract_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')
Class Method Summary
::ActiveSupport::Concern
- Extended
class_methods | Define class methods from given block. |
included | Evaluate given block in context of base class, so that you can write class macros here. |
prepended | Evaluate given block in context of base class, so that you can write class macros here. |
Instance Method Summary
-
#combined_fragment_cache_key(key)
Given a key (as described in #expire_fragment), returns a key array suitable for use in reading, writing, or expiring a cached fragment.
-
#expire_fragment(key, options = nil)
Removes fragments from the cache.
-
#fragment_exist?(key, options = nil) ⇒ Boolean
Check if a cached fragment from the location signified by
key
exists (see #expire_fragment for acceptable formats). -
#read_fragment(key, options = nil)
Reads a cached fragment from the location signified by
key
(see #expire_fragment for acceptable formats). -
#write_fragment(key, content, options = nil)
Writes
content
to the location signified bykey
(see #expire_fragment for acceptable formats).
DSL Calls
included
[ GitHub ]23 24 25 26 27 28 29 30 31 32 33 34 35
# File 'actionpack/lib/abstract_controller/caching/fragments.rb', line 23
included do if respond_to?(:class_attribute) class_attribute :fragment_cache_keys else mattr_writer :fragment_cache_keys end self.fragment_cache_keys = [] if respond_to?(:helper_method) helper_method :combined_fragment_cache_key end end
Instance Method Details
#combined_fragment_cache_key(key)
Given a key (as described in #expire_fragment), returns a key array suitable for use in reading, writing, or expiring a cached fragment. All keys begin with :views
, followed by ENV["RAILS_CACHE_ID"]
or ENV["RAILS_APP_VERSION"]
if set, followed by any controller-wide key prefix values, ending with the specified key
value.
# File 'actionpack/lib/abstract_controller/caching/fragments.rb', line 70
def combined_fragment_cache_key(key) head = self.class.fragment_cache_keys.map { |k| instance_exec(&k) } tail = key.is_a?(Hash) ? url_for(key).split("://").last : key cache_key = [:views, ENV["RAILS_CACHE_ID"] || ENV["RAILS_APP_VERSION"], head, tail] cache_key.flatten!(1) cache_key.compact! cache_key end
#expire_fragment(key, options = nil)
Removes fragments from the cache.
key
can take one of three forms:
-
::String
- This would normally take the form of a path, likepages/45/notes
. -
::Hash
- Treated as an implicit call tourl_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).
# File 'actionpack/lib/abstract_controller/caching/fragments.rb', line 134
def expire_fragment(key, = nil) return unless cache_configured? key = combined_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_exist?(key, options = nil) ⇒ Boolean
Check if a cached fragment from the location signified by key
exists (see #expire_fragment for acceptable formats).
# File 'actionpack/lib/abstract_controller/caching/fragments.rb', line 107
def fragment_exist?(key, = nil) return unless cache_configured? key = combined_fragment_cache_key(key) instrument_fragment_cache :exist_fragment?, key do cache_store.exist?(key, ) end end
#read_fragment(key, options = nil)
Reads a cached fragment from the location signified by key
(see #expire_fragment for acceptable formats).
# File 'actionpack/lib/abstract_controller/caching/fragments.rb', line 95
def read_fragment(key, = nil) return unless cache_configured? key = combined_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)
Writes content
to the location signified by key
(see #expire_fragment for acceptable formats).
# File 'actionpack/lib/abstract_controller/caching/fragments.rb', line 82
def write_fragment(key, content, = nil) return content unless cache_configured? key = combined_fragment_cache_key(key) instrument_fragment_cache :write_fragment, key do content = content.to_str cache_store.write(key, content, ) end content end