1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
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
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
require 'fileutils'
require 'uri'
module ActionController #:nodoc:
module Caching
# 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 Action Pack. This is the fastest way to cache your content as opposed to going dynamically
# through the process of 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_page</tt> class method:
#
# class WeblogController < ActionController::Base
# caches_page :show, :new
# end
#
# This will generate cache files such as <tt>weblog/show/5.html</tt> and <tt>weblog/new.html</tt>,
# 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 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.
module Pages
def self.included(base) #:nodoc:
base.extend(ClassMethods)
base.class_eval do
@@page_cache_directory = defined?(Rails.public_path) ? Rails.public_path : ""
##
# :singleton-method:
# The cache directory should be the document root for the web server and is set using <tt>Base.page_cache_directory = "/document/root"</tt>.
# For Rails, this directory has already been set to Rails.public_path (which is usually set to <tt>RAILS_ROOT + "/public"</tt>). Changing
# this setting can be useful to avoid naming conflicts with files in <tt>public/</tt>, but doing so will likely require configuring your
# web server to look in the new location for cached files.
cattr_accessor :page_cache_directory
@@page_cache_extension = '.html'
##
# :singleton-method:
# 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
# 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>.
# 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
# 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.
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.exist?(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.
#
# Usage:
#
# # cache the index action
# caches_page :index
#
# # cache the index action except for JSON requests
# caches_page :index, :if => Proc.new { |c| !c.request.format.json? }
def caches_page(*actions)
return unless perform_caching
options = actions.extract_options!
after_filter({:only => actions}.merge(options)) { |c| c.cache_page }
end
private
def page_cache_file(path)
name = (path.empty? || path == "/") ? "/index" : URI.unescape(path.chomp('/'))
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.is_a?(Hash)
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
else
self.class.expire_page(options)
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 requested url is used. Example:
# cache_page "I'm the cached content", :controller => "lists", :action => "show"
def cache_page(content = nil, options = nil)
return unless perform_caching && caching_allowed
path = case options
when Hash
url_for(options.merge(:only_path => true, :skip_relative_url_root => true, :format => params[:format]))
when String
options
else
request.path
end
self.class.cache_page(content || response.body, path)
end
private
def caching_allowed
request.get? && response.headers['Status'].to_i == 200
end
end
end
end
|
