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
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
|
require 'fileutils'
require 'active_support/core_ext/class/attribute_accessors'
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
# that would normally trigger dynamic page generation. Page caching works by configuring a web server to first check for the
# existence of files on disk, and to serve them directly when found, without passing the request through to Action Pack.
# This is much faster than handling the full dynamic request in the usual way.
#
# 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
extend ActiveSupport::Concern
included do
# 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.
class_attribute :page_cache_directory
self.page_cache_directory ||= ''
# 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.
class_attribute :page_cache_extension
self.page_cache_extension ||= '.html'
# The compression used for gzip. If false (default), the page is not compressed.
# If can be a symbol showing the ZLib compression method, for example, :best_compression
# or :best_speed or an integer configuring the compression level.
class_attribute :page_cache_compression
self.page_cache_compression ||= false
end
module ClassMethods
# Expires the page that was cached with the +path+ as a key.
#
# expire_page "/lists/show"
def expire_page(path)
return unless perform_caching
path = page_cache_path(path)
instrument_page_cache :expire_page, path do
File.delete(path) if File.exist?(path)
File.delete(path + '.gz') if File.exist?(path + '.gz')
end
end
# Manually cache the +content+ in the key determined by +path+.
#
# cache_page "I'm the cached content", "/lists/show"
def cache_page(content, path, extension = nil, gzip = Zlib::BEST_COMPRESSION)
return unless perform_caching
path = page_cache_path(path, extension)
instrument_page_cache :write_page, path do
FileUtils.makedirs(File.dirname(path))
File.open(path, "wb+") { |f| f.write(content) }
if gzip
Zlib::GzipWriter.open(path + '.gz', gzip) { |f| f.write(content) }
end
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.
#
# You can also pass a :gzip option to override the class configuration one.
#
# # cache the index action
# caches_page :index
#
# # cache the index action except for JSON requests
# caches_page :index, :if => Proc.new { !request.format.json? }
#
# # don't gzip images
# caches_page :image, :gzip => false
def caches_page(*actions)
return unless perform_caching
options = actions.extract_options!
gzip_level = options.fetch(:gzip, page_cache_compression)
gzip_level = case gzip_level
when Symbol
Zlib.const_get(gzip_level.to_s.upcase)
when Fixnum
gzip_level
when false
nil
else
Zlib::BEST_COMPRESSION
end
after_filter({:only => actions}.merge(options)) do |c|
c.cache_page(nil, nil, gzip_level)
end
end
private
def page_cache_file(path, extension)
name = (path.empty? || path == "/") ? "/index" : URI.parser.unescape(path.chomp('/'))
unless (name.split('/').last || name).include? '.'
name << (extension || self.page_cache_extension)
end
return name
end
def page_cache_path(path, extension = nil)
page_cache_directory.to_s + page_cache_file(path, extension)
end
def instrument_page_cache(name, path)
ActiveSupport::Notifications.instrument("#{name}.action_controller", :path => path){ yield }
end
end
# Expires the page that was cached with the +options+ as a key.
#
# expire_page :controller => "lists", :action => "show"
def expire_page(options = {})
return unless self.class.perform_caching
if options.is_a?(Hash)
if options[:action].is_a?(Array)
options[:action].each do |action|
self.class.expire_page(url_for(options.merge(:only_path => true, :action => action)))
end
else
self.class.expire_page(url_for(options.merge(:only_path => 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 url of the current request being handled is used.
#
# cache_page "I'm the cached content", :controller => "lists", :action => "show"
def cache_page(content = nil, options = nil, gzip = Zlib::BEST_COMPRESSION)
return unless self.class.perform_caching && caching_allowed?
path = case options
when Hash
url_for(options.merge(:only_path => true, :format => params[:format]))
when String
options
else
request.path
end
if (type = Mime::LOOKUP[self.content_type]) && (type_symbol = type.symbol).present?
extension = ".#{type_symbol}"
end
self.class.cache_page(content || response.body, path, extension, gzip)
end
end
end
end
|
