Added the option of specifying a RAILS_ASSET_HOST that will then be used by...

Added the option of specifying a RAILS_ASSET_HOST that will then be used by all the asset helpers. This enables you to easily offload static content like javascripts and images to a separate server tuned just for that.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1279 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/CHANGELOG

 *SVN*
 
+* Added the option of specifying a RAILS_ASSET_HOST that will then be used by all the asset helpers. This enables you to easily offload static content like javascripts and images to a separate server tuned just for that.
+
 * Fixed action/fragment caching using the filestore when a directory and a file wanted to to use the same name. Now there's a .cache prefix that sidesteps the conflict #1188 [imbcmdth@hotmail.com]
 
 * Fixed missing id uniqueness in FormTag#radio_button #1207 [Jarkko]

actionpack/lib/action_view/helpers/asset_tag_helper.rb

@@ -104,8 +104,8 @@ def image_tag(source, options = {})
         def compute_public_path(source, dir, ext)
           source = "/#{dir}/#{source}" unless source.include?("/")
           source = "#{source}.#{ext}" unless source.include?(".")
-          source = "#{@request.relative_url_root}#{source}" 
-          source
+          source = "#{@request.relative_url_root}#{source}"
+          defined?(RAILS_ASSET_HOST) ? RAILS_ASSET_HOST + source : source
         end
     end
   end