Module: ActionController::Caching::Fragments
- Defined in:
- lib/action_controller/caching/fragments.rb
Overview
Fragment caching is used for caching various blocks within templates 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 doing using the cache helper available in the Action View. A template with caching might look something like:
<b>Hello <%= @name %></b>
<% cache do %>
All the topics in the system:
<%= render :partial => "topic", :collection => Topic.find(:all) %>
<% end %>
This cache will bind to the name of the action that called it, so if this code was part of the view for the topics/list action, you would be able to invalidate it using expire_fragment(:controller => "topics", :action => "list")
.
This default behavior is of limited use if you need to cache multiple fragments per action or if the action itself is cached using caches_action
, so we also have the option to qualify the name of the cached fragment with something like:
<% cache(:action => "list", :action_suffix => "all_topics") do %>
That would result in a name such as “/topics/list/all_topics”, avoiding conflicts with the action cache and with any fragments that use a different suffix. Note that the URL doesn’t have to really exist or be callable - the url_for system is just used to generate unique cache names that we can refer to when we need to expire the cache.
The expiration call for this example is:
expire_fragment(:controller => "topics", :action => "list", :action_suffix => "all_topics")
Class Method Summary collapse
-
.included(base) ⇒ Object
:nodoc:.
Instance Method Summary collapse
-
#expire_fragment(key, options = nil) ⇒ Object
Name can take one of three forms: * String: This would normally take the form of a path like “pages/45/notes” * Hash: Is treated as an implicit call to url_for, like { :controller => “pages”, :action => “notes”, :id => 45 } * Regexp: Will destroy all the matched fragments, example: %rpages/d*/notes Ensure you do not specify start and finish in the regex (^$) because the actual filename matched looks like ./cache/filename/path.cache Regexp expiration is only supported on caches that can iterate over all keys (unlike memcached).
-
#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). -
#fragment_for(block, name = {}, options = nil) ⇒ 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).
Class Method Details
.included(base) ⇒ Object
:nodoc:
29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 |
# File 'lib/action_controller/caching/fragments.rb', line 29 def self.included(base) #:nodoc: base.class_eval do class << self def fragment_cache_store=(store_option) #:nodoc: ActiveSupport::Deprecation.warn('The fragment_cache_store= method is now use cache_store=') self.cache_store = store_option end def fragment_cache_store #:nodoc: ActiveSupport::Deprecation.warn('The fragment_cache_store method is now use cache_store') cache_store end end def fragment_cache_store=(store_option) #:nodoc: ActiveSupport::Deprecation.warn('The fragment_cache_store= method is now use cache_store=') self.cache_store = store_option end def fragment_cache_store #:nodoc: ActiveSupport::Deprecation.warn('The fragment_cache_store method is now use cache_store') cache_store end end end |
Instance Method Details
#expire_fragment(key, options = nil) ⇒ Object
Name can take one of three forms:
-
String: This would normally take the form of a path like “pages/45/notes”
-
Hash: Is treated as an implicit call to url_for, like { :controller => “pages”, :action => “notes”, :id => 45 }
-
Regexp: Will destroy all the matched fragments, example:
%r{pages/\d*/notes}
Ensure you do not specify start and finish in the regex (^$) because the actual filename matched looks like ./cache/filename/path.cache Regexp expiration is only supported on caches that can iterate over all keys (unlike memcached).
121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 |
# File 'lib/action_controller/caching/fragments.rb', line 121 def expire_fragment(key, = nil) return unless cache_configured? key = key.is_a?(Regexp) ? key : fragment_cache_key(key) if key.is_a?(Regexp) self.class.benchmark "Expired fragments matching: #{key.source}" do cache_store.delete_matched(key, ) end else self.class.benchmark "Expired fragment: #{key}" do 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. If the key is a hash, the generated key is the return value of url_for on that hash (without the protocol). All keys are prefixed with “views/” and uses ActiveSupport::Cache.expand_cache_key for the expansion.
59 60 61 |
# File 'lib/action_controller/caching/fragments.rb', line 59 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)
102 103 104 105 106 107 108 109 110 |
# File 'lib/action_controller/caching/fragments.rb', line 102 def fragment_exist?(key, = nil) return unless cache_configured? key = fragment_cache_key(key) self.class.benchmark "Cached fragment exists?: #{key}" do cache_store.exist?(key, ) end end |
#fragment_for(block, name = {}, options = nil) ⇒ Object
:nodoc:
63 64 65 66 67 68 69 70 71 72 73 74 75 |
# File 'lib/action_controller/caching/fragments.rb', line 63 def fragment_for(block, name = {}, = nil) #:nodoc: unless perform_caching then block.call; return end buffer = yield if cache = read_fragment(name, ) buffer.concat(cache) else pos = buffer.length block.call write_fragment(name, buffer[pos..-1], ) end end |
#read_fragment(key, options = nil) ⇒ Object
Reads a cached fragment from the location signified by key
(see expire_fragment
for acceptable formats)
91 92 93 94 95 96 97 98 99 |
# File 'lib/action_controller/caching/fragments.rb', line 91 def read_fragment(key, = nil) return unless cache_configured? key = fragment_cache_key(key) self.class.benchmark "Cached fragment hit: #{key}" do cache_store.read(key, ) end end |
#write_fragment(key, content, options = nil) ⇒ Object
Writes content
to the location signified by key
(see expire_fragment
for acceptable formats)
78 79 80 81 82 83 84 85 86 87 88 |
# File 'lib/action_controller/caching/fragments.rb', line 78 def write_fragment(key, content, = nil) return unless cache_configured? key = fragment_cache_key(key) self.class.benchmark "Cached fragment miss: #{key}" do cache_store.write(key, content, ) end content end |