154 lines
6.8 KiB
Ruby
154 lines
6.8 KiB
Ruby
require 'fileutils'
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require 'uri'
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module ActionController #:nodoc:
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module Caching
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# Page caching is an approach to caching where the entire action output of is stored as a HTML file that the web server
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# can serve without going through Action Pack. This is the fastest way to cache your content as opposed to going dynamically
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# through the process of generating the content. Unfortunately, this incredible speed-up is only available to stateless pages
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# where all visitors are treated the same. Content management systems -- including weblogs and wikis -- have many pages that are
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# a great fit for this approach, but account-based systems where people log in and manipulate their own data are often less
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# likely candidates.
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#
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# Specifying which actions to cache is done through the <tt>caches_page</tt> class method:
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#
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# class WeblogController < ActionController::Base
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# caches_page :show, :new
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# end
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#
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# This will generate cache files such as <tt>weblog/show/5.html</tt> and <tt>weblog/new.html</tt>,
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# which match the URLs used to trigger the dynamic generation. This is how the web server is able
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# pick up a cache file when it exists and otherwise let the request pass on to Action Pack to generate it.
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#
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# Expiration of the cache is handled by deleting the cached file, which results in a lazy regeneration approach where the cache
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# is not restored before another hit is made against it. The API for doing so mimics the options from +url_for+ and friends:
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#
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# class WeblogController < ActionController::Base
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# def update
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# List.update(params[:list][:id], params[:list])
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# expire_page :action => "show", :id => params[:list][:id]
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# redirect_to :action => "show", :id => params[:list][:id]
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# end
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# end
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#
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# Additionally, you can expire caches using Sweepers that act on changes in the model to determine when a cache is supposed to be
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# expired.
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#
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# == Setting the cache directory
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#
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# The cache directory should be the document root for the web server and is set using <tt>Base.page_cache_directory = "/document/root"</tt>.
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# For Rails, this directory has already been set to Rails.public_path (which is usually set to <tt>RAILS_ROOT + "/public"</tt>). Changing
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# this setting can be useful to avoid naming conflicts with files in <tt>public/</tt>, but doing so will likely require configuring your
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# web server to look in the new location for cached files.
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#
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# == Setting the cache extension
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#
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# Most Rails requests do not have an extension, such as <tt>/weblog/new</tt>. In these cases, the page caching mechanism will add one in
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# order to make it easy for the cached files to be picked up properly by the web server. By default, this cache extension is <tt>.html</tt>.
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# If you want something else, like <tt>.php</tt> or <tt>.shtml</tt>, just set Base.page_cache_extension. In cases where a request already has an
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# extension, such as <tt>.xml</tt> or <tt>.rss</tt>, page caching will not add an extension. This allows it to work well with RESTful apps.
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module Pages
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def self.included(base) #:nodoc:
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base.extend(ClassMethods)
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base.class_eval do
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@@page_cache_directory = defined?(Rails.public_path) ? Rails.public_path : ""
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cattr_accessor :page_cache_directory
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@@page_cache_extension = '.html'
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cattr_accessor :page_cache_extension
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end
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end
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module ClassMethods
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# Expires the page that was cached with the +path+ as a key. Example:
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# expire_page "/lists/show"
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def expire_page(path)
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return unless perform_caching
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benchmark "Expired page: #{page_cache_file(path)}" do
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File.delete(page_cache_path(path)) if File.exist?(page_cache_path(path))
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end
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end
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# Manually cache the +content+ in the key determined by +path+. Example:
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# cache_page "I'm the cached content", "/lists/show"
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def cache_page(content, path)
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return unless perform_caching
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benchmark "Cached page: #{page_cache_file(path)}" do
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FileUtils.makedirs(File.dirname(page_cache_path(path)))
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File.open(page_cache_path(path), "wb+") { |f| f.write(content) }
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end
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end
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# Caches the +actions+ using the page-caching approach that'll store the cache in a path within the page_cache_directory that
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# matches the triggering url.
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#
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# Usage:
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#
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# # cache the index action
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# caches_page :index
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#
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# # cache the index action except for JSON requests
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# caches_page :index, :if => Proc.new { |c| !c.request.format.json? }
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def caches_page(*actions)
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return unless perform_caching
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options = actions.extract_options!
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after_filter({:only => actions}.merge(options)) { |c| c.cache_page }
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end
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private
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def page_cache_file(path)
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name = (path.empty? || path == "/") ? "/index" : URI.unescape(path.chomp('/'))
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name << page_cache_extension unless (name.split('/').last || name).include? '.'
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return name
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end
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def page_cache_path(path)
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page_cache_directory + page_cache_file(path)
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end
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end
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# Expires the page that was cached with the +options+ as a key. Example:
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# expire_page :controller => "lists", :action => "show"
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def expire_page(options = {})
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return unless perform_caching
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if options.is_a?(Hash)
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if options[:action].is_a?(Array)
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options[:action].dup.each do |action|
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self.class.expire_page(url_for(options.merge(:only_path => true, :skip_relative_url_root => true, :action => action)))
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end
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else
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self.class.expire_page(url_for(options.merge(:only_path => true, :skip_relative_url_root => true)))
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end
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else
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self.class.expire_page(options)
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end
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end
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# Manually cache the +content+ in the key determined by +options+. If no content is provided, the contents of response.body is used
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# If no options are provided, the requested url is used. Example:
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# cache_page "I'm the cached content", :controller => "lists", :action => "show"
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def cache_page(content = nil, options = nil)
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return unless perform_caching && caching_allowed
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path = case options
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when Hash
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url_for(options.merge(:only_path => true, :skip_relative_url_root => true, :format => params[:format]))
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when String
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options
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else
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request.path
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end
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self.class.cache_page(content || response.body, path)
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end
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private
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def caching_allowed
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request.get? && response.headers['Status'].to_i == 200
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end
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end
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end
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end |