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Diffstat (limited to 'actionpack/lib/action_controller/caching/fragments.rb')
| -rw-r--r-- | actionpack/lib/action_controller/caching/fragments.rb | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/actionpack/lib/action_controller/caching/fragments.rb b/actionpack/lib/action_controller/caching/fragments.rb new file mode 100644 index 0000000000..868af19780 --- /dev/null +++ b/actionpack/lib/action_controller/caching/fragments.rb @@ -0,0 +1,153 @@ +module ActionController #:nodoc: + module Caching + # 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 <tt>expire_fragment(:controller => "topics", :action => "list")</tt>. + # + # This default behavior is of limited use if you need to cache multiple fragments per action or if the action itself is cached using + # <tt>caches_action</tt>, 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") + module Fragments + 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 + + # Given a key (as described in <tt>expire_fragment</tt>), 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. + def fragment_cache_key(key) + ActiveSupport::Cache.expand_cache_key(key.is_a?(Hash) ? url_for(key).split("://").last : key, :views) + end + + def fragment_for(block, name = {}, options = nil) #:nodoc: + unless perform_caching then block.call; return end + + buffer = yield + + if cache = read_fragment(name, options) + buffer.concat(cache) + else + pos = buffer.length + block.call + write_fragment(name, buffer[pos..-1], options) + end + end + + # Called by CacheHelper#cache + def cache_rxml_fragment(block, name = {}, options = nil) #:nodoc: + fragment_for(block, name, options) do + eval('xml.target!', block.binding) + end + end + + # Called by CacheHelper#cache + def cache_rjs_fragment(block, name = {}, options = nil) #:nodoc: + fragment_for(block, name, options) do + begin + debug_mode, ActionView::Base.debug_rjs = ActionView::Base.debug_rjs, false + eval('page.to_s', block.binding) + ensure + ActionView::Base.debug_rjs = debug_mode + end + end + end + + # Called by CacheHelper#cache + def cache_erb_fragment(block, name = {}, options = nil) #:nodoc: + fragment_for(block, name, options) do + eval(ActionView::Base.erb_variable, block.binding) + end + end + + # Writes <tt>content</tt> to the location signified by <tt>key</tt> (see <tt>expire_fragment</tt> for acceptable formats) + def write_fragment(key, content, options = nil) + return unless cache_configured? + + key = fragment_cache_key(key) + + self.class.benchmark "Cached fragment miss: #{key}" do + cache_store.write(key, content, options) + end + + content + end + + # Reads a cached fragment from the location signified by <tt>key</tt> (see <tt>expire_fragment</tt> for acceptable formats) + def read_fragment(key, options = nil) + return unless cache_configured? + + key = fragment_cache_key(key) + + self.class.benchmark "Cached fragment hit: #{key}" do + cache_store.read(key, options) + end + end + + # 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). + def expire_fragment(key, options = 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, options) + end + else + self.class.benchmark "Expired fragment: #{key}" do + cache_store.delete(key, options) + end + end + end + end + end +end
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