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require 'fileutils'
require 'uri'
module ActionController #:nodoc:
# Caching is a cheap way of speeding up slow applications by keeping the result of calculations, renderings, and database calls
# around for subsequent requests. Action Controller affords you three approaches in varying levels of granularity: Page, Action, Fragment.
#
# You can read more about each approach and the sweeping assistance by clicking the modules below.
#
# Note: To turn off all caching and sweeping, set Base.perform_caching = false.
module Caching
def self.included(base) #:nodoc:
base.send(:include, Pages, Actions, Fragments, Sweeping)
base.class_eval do
@@perform_caching = true
cattr_accessor :perform_caching
end
end
# Page caching is an approach to caching where the entire action output of is stored as a HTML file that the web server
# can serve without going through the Action Pack. This can be as much as 100 times faster than going through the process of dynamically
# generating the content. Unfortunately, this incredible speed-up is only available to stateless pages where all visitors
# are treated the same. Content management systems -- including weblogs and wikis -- have many pages that are a great fit
# for this approach, but account-based systems where people log in and manipulate their own data are often less likely candidates.
#
# Specifying which actions to cache is done through the <tt>caches</tt> class method:
#
# class WeblogController < ActionController::Base
# caches_page :show, :new
# end
#
# This will generate cache files such as weblog/show/5 and weblog/new, which match the URLs used to trigger the dynamic
# generation. This is how the web server is able pick up a cache file when it exists and otherwise let the request pass on to
# the Action Pack to generate it.
#
# Expiration of the cache is handled by deleting the cached file, which results in a lazy regeneration approach where the cache
# is not restored before another hit is made against it. The API for doing so mimics the options from url_for and friends:
#
# class WeblogController < ActionController::Base
# def update
# List.update(params[:list][:id], params[:list])
# expire_page :action => "show", :id => params[:list][:id]
# redirect_to :action => "show", :id => params[:list][:id]
# end
# end
#
# Additionally, you can expire caches using Sweepers that act on changes in the model to determine when a cache is supposed to be
# expired.
#
# == Setting the cache directory
#
# The cache directory should be the document root for the web server and is set using Base.page_cache_directory = "/document/root".
# For Rails, this directory has already been set to RAILS_ROOT + "/public".
#
# == Setting the cache extension
#
# By default, the cache extension is .html, which makes it easy for the cached files to be picked up by the web server. If you want
# something else, like .php or .shtml, just set Base.page_cache_extension.
module Pages
def self.included(base) #:nodoc:
base.extend(ClassMethods)
base.class_eval do
@@page_cache_directory = defined?(RAILS_ROOT) ? "#{RAILS_ROOT}/public" : ""
cattr_accessor :page_cache_directory
@@page_cache_extension = '.html'
cattr_accessor :page_cache_extension
end
end
module ClassMethods
# Expires the page that was cached with the +path+ as a key. Example:
# expire_page "/lists/show"
def expire_page(path)
return unless perform_caching
benchmark "Expired page: #{page_cache_file(path)}" do
File.delete(page_cache_path(path)) if File.exists?(page_cache_path(path))
end
end
# Manually cache the +content+ in the key determined by +path+. Example:
# cache_page "I'm the cached content", "/lists/show"
def cache_page(content, path)
return unless perform_caching
benchmark "Cached page: #{page_cache_file(path)}" do
FileUtils.makedirs(File.dirname(page_cache_path(path)))
File.open(page_cache_path(path), "wb+") { |f| f.write(content) }
end
end
# Caches the +actions+ using the page-caching approach that'll store the cache in a path within the page_cache_directory that
# matches the triggering url.
def caches_page(*actions)
return unless perform_caching
actions.each do |action|
class_eval "after_filter { |c| c.cache_page if c.action_name == '#{action}' }"
end
end
private
def page_cache_file(path)
name = ((path.empty? || path == "/") ? "/index" : URI.unescape(path))
name << page_cache_extension unless (name.split('/').last || name).include? '.'
return name
end
def page_cache_path(path)
page_cache_directory + page_cache_file(path)
end
end
# Expires the page that was cached with the +options+ as a key. Example:
# expire_page :controller => "lists", :action => "show"
def expire_page(options = {})
return unless perform_caching
if options[:action].is_a?(Array)
options[:action].dup.each do |action|
self.class.expire_page(url_for(options.merge({ :only_path => true, :skip_relative_url_root => true, :action => action })))
end
else
self.class.expire_page(url_for(options.merge({ :only_path => true, :skip_relative_url_root => true })))
end
end
# Manually cache the +content+ in the key determined by +options+. If no content is provided, the contents of @response.body is used
# If no options are provided, the current +options+ for this action is used. Example:
# cache_page "I'm the cached content", :controller => "lists", :action => "show"
def cache_page(content = nil, options = {})
return unless perform_caching && caching_allowed
self.class.cache_page(content || @response.body, url_for(options.merge({ :only_path => true, :skip_relative_url_root => true })))
end
private
def caching_allowed
!@request.post? && @response.headers['Status'] && @response.headers['Status'].to_i < 400
end
end
# Action caching is similar to page caching by the fact that the entire output of the response is cached, but unlike page caching,
# every request still goes through the Action Pack. The key benefit of this is that filters are run before the cache is served, which
# allows for authentication and other restrictions on whether someone is allowed to see the cache. Example:
#
# class ListsController < ApplicationController
# before_filter :authenticate, :except => :public
# caches_page :public
# caches_action :show, :feed
# end
#
# In this example, the public action doesn't require authentication, so it's possible to use the faster page caching method. But both the
# show and feed action are to be shielded behind the authenticate filter, so we need to implement those as action caches.
#
# Action caching internally uses the fragment caching and an around filter to do the job. The fragment cache is named according to both
# the current host and the path. So a page that is accessed at http://david.somewhere.com/lists/show/1 will result in a fragment named
# "david.somewhere.com/lists/show/1". This allows the cacher to differentiate between "david.somewhere.com/lists/" and
# "jamis.somewhere.com/lists/" -- which is a helpful way of assisting the subdomain-as-account-key pattern.
#
# Different representations of the same resource, e.g. <tt>http://david.somewhere.com/lists</tt> and <tt>http://david.somewhere.com/lists.xml</tt>
# are treated like separate requests and so are cached separately. Keep in mine when expiring an action cache that <tt>:action => 'lists'</tt> is not the same
# as <tt>:action => 'list', :format => :xml</tt>.
module Actions
def self.included(base) #:nodoc:
base.extend(ClassMethods)
base.send(:attr_accessor, :rendered_action_cache)
end
module ClassMethods #:nodoc:
def caches_action(*actions)
return unless perform_caching
around_filter(ActionCacheFilter.new(*actions))
end
end
def expire_action(options = {})
return unless perform_caching
if options[:action].is_a?(Array)
options[:action].dup.each do |action|
expire_fragment(ActionCachePath.path_for(self, options.merge({ :action => action })))
end
else
expire_fragment(ActionCachePath.path_for(self, options))
end
end
class ActionCacheFilter #:nodoc:
def initialize(*actions, &block)
@actions = actions
end
def before(controller)
return unless @actions.include?(controller.action_name.intern)
action_cache_path = ActionCachePath.new(controller)
if cache = controller.read_fragment(action_cache_path.path)
controller.rendered_action_cache = true
set_content_type!(action_cache_path)
controller.send(:render_text, cache)
false
end
end
def after(controller)
return if !@actions.include?(controller.action_name.intern) || controller.rendered_action_cache
controller.write_fragment(ActionCachePath.path_for(controller), controller.response.body)
end
private
def set_content_type!(action_cache_path)
if extention = action_cache_path.extension
content_type = Mime::EXTENSION_LOOKUP[extention]
action_cache_path.controller.headers['Content-Type'] = content_type.to_s
end
end
end
class ActionCachePath
attr_reader :controller, :options
class << self
def path_for(*args, &block)
new(*args).path
end
end
def initialize(controller, options = {})
@controller = controller
@options = options
end
def path
return @path if @path
@path = controller.url_for(options).split('://').last
normalize!
add_extension!
URI.unescape(@path)
end
def extension
@extension ||= extract_extension(controller.request.path)
end
private
def normalize!
@path << 'index' if @path.last == '/'
end
def add_extension!
@path << ".#{extension}" if extension
end
def extract_extension(file_path)
# Don't want just what comes after the last '.' to accomodate multi part extensions
# such as tar.gz.
file_path[/^[^.]+\.(.+)$/, 1]
end
end
end
# 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_collection_of_partials "topic", Topic.find_all %>
# <% end %>
#
# This cache will bind to the name of action that called it. So you would be able to invalidate it using
# <tt>expire_fragment(:controller => "topics", :action => "list")</tt> -- if that was the controller/action used. This is not too helpful
# if you need to cache multiple fragments per action or if the action itself is cached using <tt>caches_action</tt>. So instead we should
# qualify the name of the action used with something like:
#
# <% cache(:action => "list", :action_suffix => "all_topics") do %>
#
# That would result in a name such as "/topics/list/all_topics", which wouldn't conflict with any action cache and neither with another
# fragment using a different suffix. Note that the URL doesn't have to really exist or be callable. We're just using the url_for system
# to generate unique cache names that we can refer to later for expirations. The expiration call for this example would be
# <tt>expire_fragment(:controller => "topics", :action => "list", :action_suffix => "all_topics")</tt>.
#
# == Fragment stores
#
# In order to use the fragment caching, you need to designate where the caches should be stored. This is done by assigning a fragment store
# of which there are four different kinds:
#
# * FileStore: Keeps the fragments on disk in the +cache_path+, which works well for all types of environments and shares the fragments for
# all the web server processes running off the same application directory.
# * MemoryStore: Keeps the fragments in memory, which is fine for WEBrick and for FCGI (if you don't care that each FCGI process holds its
# own fragment store). It's not suitable for CGI as the process is thrown away at the end of each request. It can potentially also take
# up a lot of memory since each process keeps all the caches in memory.
# * DRbStore: Keeps the fragments in the memory of a separate, shared DRb process. This works for all environments and only keeps one cache
# around for all processes, but requires that you run and manage a separate DRb process.
# * MemCacheStore: Works like DRbStore, but uses Danga's MemCache instead.
# Requires the ruby-memcache library: gem install ruby-memcache.
#
# Configuration examples (MemoryStore is the default):
#
# ActionController::Base.fragment_cache_store = :memory_store
# ActionController::Base.fragment_cache_store = :file_store, "/path/to/cache/directory"
# ActionController::Base.fragment_cache_store = :drb_store, "druby://localhost:9192"
# ActionController::Base.fragment_cache_store = :mem_cache_store, "localhost"
# ActionController::Base.fragment_cache_store = MyOwnStore.new("parameter")
module Fragments
def self.included(base) #:nodoc:
base.class_eval do
@@fragment_cache_store = MemoryStore.new
cattr_reader :fragment_cache_store
def self.fragment_cache_store=(store_option)
store, *parameters = *([ store_option ].flatten)
@@fragment_cache_store = if store.is_a?(Symbol)
store_class_name = (store == :drb_store ? "DRbStore" : store.to_s.camelize)
store_class = ActionController::Caching::Fragments.const_get(store_class_name)
store_class.new(*parameters)
else
store
end
end
end
end
def fragment_cache_key(name)
name.is_a?(Hash) ? url_for(name).split("://").last : name
end
# Called by CacheHelper#cache
def cache_erb_fragment(block, name = {}, options = nil)
unless perform_caching then block.call; return end
buffer = eval("_erbout", block.binding)
if cache = read_fragment(name, options)
buffer.concat(cache)
else
pos = buffer.length
block.call
write_fragment(name, buffer[pos..-1], options)
end
end
def write_fragment(name, content, options = nil)
return unless perform_caching
key = fragment_cache_key(name)
self.class.benchmark "Cached fragment: #{key}" do
fragment_cache_store.write(key, content, options)
end
content
end
def read_fragment(name, options = nil)
return unless perform_caching
key = fragment_cache_key(name)
self.class.benchmark "Fragment read: #{key}" do
fragment_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
def expire_fragment(name, options = nil)
return unless perform_caching
key = fragment_cache_key(name)
if key.is_a?(Regexp)
self.class.benchmark "Expired fragments matching: #{key.source}" do
fragment_cache_store.delete_matched(key, options)
end
else
self.class.benchmark "Expired fragment: #{key}" do
fragment_cache_store.delete(key, options)
end
end
end
# Deprecated -- just call expire_fragment with a regular expression
def expire_matched_fragments(matcher = /.*/, options = nil) #:nodoc:
expire_fragment(matcher, options)
end
class UnthreadedMemoryStore #:nodoc:
def initialize #:nodoc:
@data = {}
end
def read(name, options=nil) #:nodoc:
@data[name]
end
def write(name, value, options=nil) #:nodoc:
@data[name] = value
end
def delete(name, options=nil) #:nodoc:
@data.delete(name)
end
def delete_matched(matcher, options=nil) #:nodoc:
@data.delete_if { |k,v| k =~ matcher }
end
end
module ThreadSafety #:nodoc:
def read(name, options=nil) #:nodoc:
@mutex.synchronize { super }
end
def write(name, value, options=nil) #:nodoc:
@mutex.synchronize { super }
end
def delete(name, options=nil) #:nodoc:
@mutex.synchronize { super }
end
def delete_matched(matcher, options=nil) #:nodoc:
@mutex.synchronize { super }
end
end
class MemoryStore < UnthreadedMemoryStore #:nodoc:
def initialize #:nodoc:
super
if ActionController::Base.allow_concurrency
@mutex = Mutex.new
MemoryStore.send(:include, ThreadSafety)
end
end
end
class DRbStore < MemoryStore #:nodoc:
attr_reader :address
def initialize(address = 'druby://localhost:9192')
super()
@address = address
@data = DRbObject.new(nil, address)
end
end
class MemCacheStore < MemoryStore #:nodoc:
attr_reader :addresses
def initialize(*addresses)
super()
addresses = addresses.flatten
addresses = ["localhost"] if addresses.empty?
@addresses = addresses
@data = MemCache.new(*addresses)
end
end
class UnthreadedFileStore #:nodoc:
attr_reader :cache_path
def initialize(cache_path)
@cache_path = cache_path
end
def write(name, value, options = nil) #:nodoc:
ensure_cache_path(File.dirname(real_file_path(name)))
File.open(real_file_path(name), "wb+") { |f| f.write(value) }
rescue => e
Base.logger.error "Couldn't create cache directory: #{name} (#{e.message})" if Base.logger
end
def read(name, options = nil) #:nodoc:
File.open(real_file_path(name), 'rb') { |f| f.read } rescue nil
end
def delete(name, options) #:nodoc:
File.delete(real_file_path(name))
rescue SystemCallError => e
# If there's no cache, then there's nothing to complain about
end
def delete_matched(matcher, options) #:nodoc:
search_dir(@cache_path) do |f|
if f =~ matcher
begin
File.delete(f)
rescue Object => e
# If there's no cache, then there's nothing to complain about
end
end
end
end
private
def real_file_path(name)
'%s/%s.cache' % [@cache_path, name.gsub('?', '.').gsub(':', '.')]
end
def ensure_cache_path(path)
FileUtils.makedirs(path) unless File.exists?(path)
end
def search_dir(dir, &callback)
Dir.foreach(dir) do |d|
next if d == "." || d == ".."
name = File.join(dir, d)
if File.directory?(name)
search_dir(name, &callback)
else
callback.call name
end
end
end
end
class FileStore < UnthreadedFileStore #:nodoc:
def initialize(cache_path)
super(cache_path)
if ActionController::Base.allow_concurrency
@mutex = Mutex.new
FileStore.send(:include, ThreadSafety)
end
end
end
end
# Sweepers are the terminators of the caching world and responsible for expiring caches when model objects change.
# They do this by being half-observers, half-filters and implementing callbacks for both roles. A Sweeper example:
#
# class ListSweeper < ActionController::Caching::Sweeper
# observe List, Item
#
# def after_save(record)
# list = record.is_a?(List) ? record : record.list
# expire_page(:controller => "lists", :action => %w( show public feed ), :id => list.id)
# expire_action(:controller => "lists", :action => "all")
# list.shares.each { |share| expire_page(:controller => "lists", :action => "show", :id => share.url_key) }
# end
# end
#
# The sweeper is assigned in the controllers that wish to have its job performed using the <tt>cache_sweeper</tt> class method:
#
# class ListsController < ApplicationController
# caches_action :index, :show, :public, :feed
# cache_sweeper :list_sweeper, :only => [ :edit, :destroy, :share ]
# end
#
# In the example above, four actions are cached and three actions are responsible for expiring those caches.
module Sweeping
def self.included(base) #:nodoc:
base.extend(ClassMethods)
end
module ClassMethods #:nodoc:
def cache_sweeper(*sweepers)
return unless perform_caching
configuration = sweepers.last.is_a?(Hash) ? sweepers.pop : {}
sweepers.each do |sweeper|
observer(sweeper)
sweeper_instance = Object.const_get(Inflector.classify(sweeper)).instance
if sweeper_instance.is_a?(Sweeper)
around_filter(sweeper_instance, :only => configuration[:only])
else
after_filter(sweeper_instance, :only => configuration[:only])
end
end
end
end
end
if defined?(ActiveRecord) and defined?(ActiveRecord::Observer)
class Sweeper < ActiveRecord::Observer #:nodoc:
attr_accessor :controller
# ActiveRecord::Observer will mark this class as reloadable even though it should not be.
# However, subclasses of ActionController::Caching::Sweeper should be Reloadable
include Reloadable::Deprecated
def before(controller)
self.controller = controller
callback(:before)
end
def after(controller)
callback(:after)
# Clean up, so that the controller can be collected after this request
self.controller = nil
end
private
def callback(timing)
controller_callback_method_name = "#{timing}_#{controller.controller_name.underscore}"
action_callback_method_name = "#{controller_callback_method_name}_#{controller.action_name}"
send(controller_callback_method_name) if respond_to?(controller_callback_method_name)
send(action_callback_method_name) if respond_to?(action_callback_method_name)
end
def method_missing(method, *arguments)
return if @controller.nil?
@controller.send(method, *arguments)
end
end
end
end
end
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