Changeset 6161

Timestamp:

02/18/07 06:44:20 (2 years ago)

Author:

bitsweat

Message:

Work around the two connection per host browser limit: use asset%d.myapp.com to distribute asset requests among asset[0123].myapp.com. Use a DNS wildcard or CNAMEs to map these hosts to your asset server. See http://www.die.net/musings/page_load_time/ for background.

Files:

• trunk/actionpack/CHANGELOG (modified) (1 diff)
• trunk/actionpack/lib/action_view/helpers/asset_tag_helper.rb (modified) (8 diffs)
• trunk/actionpack/test/template/asset_tag_helper_test.rb (modified) (1 diff)

trunk/actionpack/CHANGELOG

@@ -1 +1 @@
-*SVN*
+
+* Work around the two connection per host browser limit: use asset%d.myapp.com to distribute asset requests among asset[0123].myapp.com. Use a DNS wildcard or CNAMEs to map these hosts to your asset server. See http://www.die.net/musings/page_load_time/ for background.  [Jeremy Kemper]
-
-* Added default mime type for CSS (Mime::CSS) [DHH]

trunk/actionpack/lib/action_view/helpers/asset_tag_helper.rb

@@ -12 +12 @@
-    #
-    #   ActionController::Base.asset_host = "http://assets.example.com"
-  
+
-    #     => <img src="http://assets.example.com/images/rails.png" alt="Rails" />
-    #   stylesheet_include_tag("application")
-    #     => <link href="http://assets.example.com/stylesheets/application.css" media="screen" rel="Stylesheet" type="text/css" />
+    #
+    # Since browsers typically open at most two connections to a single host,
+    # your assets often wait in single file for their turn to load.
+    #
+    # Use a %d wildcard in asset_host (asset%d.myapp.com) to automatically
+    # distribute asset requests among four hosts (asset0-asset3.myapp.com)
+    # so browsers will open eight connections rather than two.  Use wildcard
+    # DNS to CNAME the wildcard to your real asset host.
+    #
+    # Note: this is purely a browser performance optimization and is not meant
+    # for server load balancing. See http://www.die.net/musings/page_load_time/
+    # for background.
-    module AssetTagHelper
-      # Returns a link tag that browsers and news readers can use to auto-detect
- 
+
-      # <tt>:atom</tt>. Control the link options in url_for format using the
-      # +url_options+. You can modify the LINK tag itself in +tag_options+.
@@ -37 +49 @@
-      def auto_discovery_link_tag(type = :rss, url_options = {}, tag_options = {})
-        tag(
- 
+
-          "rel"   => tag_options[:rel] || "alternate",
-          "type"  => tag_options[:type] || Mime::Type.lookup_by_extension(type.to_s).to_s,
@@ -54 +66 @@
-      #   javascript_path "/dir/xmlhr" # => /dir/xmlhr.js
-      def javascript_path(source)
-        
+
-      end
-
@@ -65 +77 @@
-      # current page or you can pass the full path relative to your document
-      # root. To include the Prototype and Scriptaculous javascript libraries in
- 
- 
- 
- 
+
+
+
+
-      #
-      #   javascript_include_tag "xmlhr" # =>
@@ -85 +97 @@
-        options = sources.last.is_a?(Hash) ? sources.pop.stringify_keys : { }
-
- 
- 
- 
+
+
+
-            sources[(sources.index(:defaults) + 1)..sources.length]
-
- 
- 
+
+
-        end
-
-        sources.collect do |source|
-        
+
-          content_tag("script", "", { "type" => "text/javascript", "src" => source }.merge(options))
-        end.join("\n")
-      end
-
+
-      # Register one or more additional JavaScript files to be included when
-      # <tt>javascript_include_tag :defaults</tt> is called. This method is
- 
+
-      # .js files that the plugin installed in <tt>public/javascripts</tt>.
-      def self.register_javascript_include_default(*sources)
-        @@javascript_default_sources.concat(sources)
-      end
-
+
-      def self.reset_javascript_include_default #:nodoc:
-        @@javascript_default_sources = JAVASCRIPT_DEFAULT_SOURCES.dup
@@ -166 +178 @@
-
-      # Returns an html image tag for the +source+. The +source+ can be a full
- 
+
-      # specifying a filename without the extension is now deprecated in Rails.
-      # You can add html attributes using the +options+. The +options+ supports
-      # two additional keys for convienence and conformance:
-      #
- 
+
-      #   +source+ is used (capitalized and without the extension)
- 
+
-      #   width="30" and height="45". <tt>:size</tt> will be ignored if the
-      #   value is not in the correct format.
@@ -185 +197 @@
-      def image_tag(source, options = {})
-        options.symbolize_keys!
-
+
-        options[:src] = image_path(source)
-        options[:alt] ||= File.basename(options[:src], '.*').split('.').first.capitalize
-
+
-        if options[:size]
-          options[:width], options[:height] = options[:size].split("x") if options[:size] =~ %r{^\d+x\d+$}
@@ -196 +208 @@
-        tag("img", options)
-      end
-
+
-      private
+        # Add the .ext if not present. Return full URLs otherwise untouched.
+        # Prefix with /dir/ if lacking a leading /. Account for relative URL
+        # roots. Rewrite the asset path for cache-busting asset ids. Include
+        # a single or wildcarded asset host if configured.
-        def compute_public_path(source, dir, ext)
-
-
-
+
+
+
+
-            source = "/#{dir}/#{source}" unless source[0] == ?/
-asset_id = rails_asset_id(source)
-source << '?' + asset_id if defined?(RAILS_ROOT) && !asset_id.blank?
-source = "#{ActionController::Base.asset_host}#{@controller.request.relative_url_root
+source = "#{@controller.request.relative_url_root}#{source}"
+rewrite_asset_path!(source)
+"#{compute_asset_host(source)
-          end
-
-
-
+
+
+
+
+
+
+
+
+
+
+
+
+
-        def rails_asset_id(source)
- 
+
-            File.mtime("#{RAILS_ROOT}/public/#{source}").to_i.to_s rescue ""
+        end
+
+        # Break out the asset path rewrite so you wish to put the asset id
+        # someplace other than the query string.
+        def rewrite_asset_path!(source)
+          asset_id = rails_asset_id(source)
+          source << "?#{asset_id}" if defined?(RAILS_ROOT) && !asset_id.blank?
-        end
-    end

trunk/actionpack/test/template/asset_tag_helper_test.rb

@@ -224 +224 @@
-    ActionController::Base.asset_host = ""
-  end
+
+  def test_should_wildcard_asset_host_between_zero_and_four
+    ActionController::Base.asset_host = 'http://a%d.example.com'
+    assert_match %r(http://a[0123].example.com/collaboration/hieraki/images/xml.png), image_path('xml.png')
+  ensure
+    ActionController::Base.asset_host = nil
+  end
-end