Gzip files on page caching

Signed-off-by: José Valim <jose.valim@gmail.com>

actionpack/lib/action_controller/caching/pages.rb

@@ -66,24 +66,30 @@ module ActionController #:nodoc:
 
           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+. Example:
         #   cache_page "I'm the cached content", "/lists/show"
-        def cache_page(content, path, extension = nil)
+        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 disable gzipping by setting +:gzip+ option to false.
+        #
         # Usage:
         #
         #   # cache the index action
@@ -91,10 +97,28 @@ module ActionController #:nodoc:
         #
         #   # cache the index action except for JSON requests
         #   caches_page :index, :if => Proc.new { |c| !c.request.format.json? }
+        #
+        #   # don't gzip images
+        #   caches_page :image, :gzip => false
         def caches_page(*actions)
           return unless perform_caching
           options = actions.extract_options!
-          after_filter({:only => actions}.merge(options)) { |c| c.cache_page }
+
+          gzip_level = options.fetch(:gzip, :best_compression)
+          if gzip_level
+            gzip_level = case gzip_level
+              when Symbol
+                Zlib.const_get(gzip_level.to_s.upcase)
+              when Fixnum
+                gzip_level
+              else
+                Zlib::BEST_COMPRESSION
+            end
+          end
+
+          after_filter({:only => actions}.merge(options)) do |c|
+            c.cache_page(nil, nil, gzip_level)
+          end
         end
 
         private
@@ -136,7 +160,7 @@ module ActionController #:nodoc:
       # 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. Example:
       #   cache_page "I'm the cached content", :controller => "lists", :action => "show"
-      def cache_page(content = nil, options = nil)
+      def cache_page(content = nil, options = nil, gzip = Zlib::BEST_COMPRESSION)
         return unless self.class.perform_caching && caching_allowed?
 
         path = case options
@@ -152,7 +176,7 @@ module ActionController #:nodoc:
           extension = ".#{type_symbol}"
         end
 
-        self.class.cache_page(content || response.body, path, extension)
+        self.class.cache_page(content || response.body, path, extension, gzip)
       end
 
     end

actionpack/test/controller/caching_test.rb

@@ -17,6 +17,9 @@ class PageCachingTestController < CachingController
   caches_page :ok, :no_content, :if => Proc.new { |c| !c.request.format.json? }
   caches_page :found, :not_found
   caches_page :about_me
+  caches_page :default_gzip
+  caches_page :no_gzip, :gzip => false
+  caches_page :gzip_level, :gzip => :best_speed
 
 
   def ok
@@ -40,6 +43,18 @@ class PageCachingTestController < CachingController
     cache_page("Super soaker", "/index.html")
   end
 
+  def default_gzip
+    render :text => "Text"
+  end
+
+  def no_gzip
+    render :text => "PNG"
+  end
+
+  def gzip_level
+    render :text => "Big text"
+  end
+
   def expire_custom_path
     expire_page("/index.html")
     head :ok
@@ -115,6 +130,30 @@ class PageCachingTest < ActionController::TestCase
     assert !File.exist?("#{FILE_STORE_PATH}/index.html")
   end
 
+  def test_should_gzip_cache
+    get :custom_path
+    assert File.exist?("#{FILE_STORE_PATH}/index.html.gz")
+
+    get :expire_custom_path
+    assert !File.exist?("#{FILE_STORE_PATH}/index.html.gz")
+  end
+
+  def test_should_allow_to_disable_gzip
+    get :no_gzip
+    assert File.exist?("#{FILE_STORE_PATH}/page_caching_test/no_gzip.html")
+    assert !File.exist?("#{FILE_STORE_PATH}/page_caching_test/no_gzip.html.gz")
+  end
+
+  def test_should_use_best_gzip_by_default
+    @controller.expects(:cache_page).with(nil, nil, Zlib::BEST_COMPRESSION)
+    get :default_gzip
+  end
+
+  def test_should_set_gzip_level
+    @controller.expects(:cache_page).with(nil, nil, Zlib::BEST_SPEED)
+    get :gzip_level
+  end
+
   def test_should_cache_without_trailing_slash_on_url
     @controller.class.cache_page 'cached content', '/page_caching_test/trailing_slash'
     assert File.exist?("#{FILE_STORE_PATH}/page_caching_test/trailing_slash.html")
@@ -224,7 +263,7 @@ class ActionCachingTestController < CachingController
     @cache_this = MockTime.now.to_f.to_s
     render :text => @cache_this
   end
-  
+
   def record_not_found
     raise ActiveRecord::RecordNotFound, "oops!"
   end

railties/guides/source/caching_with_rails.textile

@@ -64,6 +64,28 @@ end
 
 If you want a more complicated expiration scheme, you can use cache sweepers to expire cached objects when things change. This is covered in the section on Sweepers.
 
+By default, page caching automatically gzips file (for example, to +products.html.gz+ if user requests +/products+) to reduce size of transmitted data (web servers are typically configured to use a moderate compression ratio as a compromise, but since precompilation happens once, compression ration is maximum).
+
+Nginx is able to serve compressed content directly from disk by enabling +gzip_static+:
+
+<plain>
+location /  {
+  gzip_static on; # to serve pre-gzipped version
+}
+</plain>
+
+You can disable gzipping by setting +:gzip+ option to false (for example, if action returns image):
+
+<ruby>
+    caches_page :image, :gzip => false
+</ruby>
+
+Or, you can set custom gzip compression level (level names are taken from +Zlib+ constants):
+
+<ruby>
+    caches_page :image, :gzip => :best_speed
+</ruby>
+
 NOTE: Page caching ignores all parameters. For example +/products?page=1+ will be written out to the filesystem as +products.html+ with no reference to the +page+ parameter. Thus, if someone requests +/products?page=2+ later, they will get the cached first page. A workaround for this limitation is to include the parameters in the page's path, e.g. +/productions/page/1+.
 
 INFO: Page caching runs in an after filter. Thus, invalid requests won't generate spurious cache entries as long as you halt them. Typically, a redirection in some before filter that checks request preconditions does the job.