Added automated timestamping to AssetTagHelper methods for stylesheets, javascripts, and images when Action Controller is run under Rails [DHH]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4098 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/CHANGELOG

@@ -1,3 +1,16 @@
+*SVN*
+
+* Added automated timestamping to AssetTagHelper methods for stylesheets, javascripts, and images when Action Controller is run under Rails [DHH]. Example:
+
+    image_tag("rails.png") # => '<img alt="Rails" src="/images/rails.png?1143664135" />'
+  
+  ...to avoid frequent stats (not a problem for most people), you can set RAILS_ASSET_ID in the ENV to avoid stats:
+
+    ENV["RAILS_ASSET_ID"] = "2345"
+    image_tag("rails.png") # => '<img alt="Rails" src="/images/rails.png?2345" />'
+
+  This can be used by deployment managers to set the asset id by application revision
+
 *1.12.0* (March 27th, 2005)
 
 * Add documentation for respond_to. [Jamis Buck]

actionpack/lib/action_view/helpers/asset_tag_helper.rb

@@ -59,11 +59,16 @@ module ActionView
       # <tt>controllers/application.rb</tt> and <tt>helpers/application_helper.rb</tt>.
       def javascript_include_tag(*sources)
         options = sources.last.is_a?(Hash) ? sources.pop.stringify_keys : { }
+
         if sources.include?(:defaults) 
-          sources = sources[0..(sources.index(:defaults))] + @@javascript_default_sources.dup + sources[(sources.index(:defaults) + 1)..sources.length] 
+          sources = sources[0..(sources.index(:defaults))] + 
+            @@javascript_default_sources.dup + 
+            sources[(sources.index(:defaults) + 1)..sources.length]
+
           sources.delete(:defaults) 
-          sources << "application" if defined?(RAILS_ROOT) and File.exists?("#{RAILS_ROOT}/public/javascripts/application.js") 
+          sources << "application" if defined?(RAILS_ROOT) && File.exists?("#{RAILS_ROOT}/public/javascripts/application.js") 
         end
+
         sources.collect { |source|
           source = javascript_path(source)        
           content_tag("script", "", { "type" => "text/javascript", "src" => source }.merge(options))
@@ -145,12 +150,18 @@ module ActionView
       
       private
         def compute_public_path(source, dir, ext)
-          source = "/#{dir}/#{source}" unless source.first == "/" || source.include?(":")
-          source = "#{source}.#{ext}" unless source.split("/").last.include?(".")
-          source = "#{@controller.request.relative_url_root}#{source}" unless %r{^[-a-z]+://} =~ source
+          source  = "/#{dir}/#{source}" unless source.first == "/" || source.include?(":")
+          source << ".#{ext}" unless source.split("/").last.include?(".")
+          source << '?' + rails_asset_id(source) if defined?(RAILS_ROOT)
+          source  = "#{@controller.request.relative_url_root}#{source}" unless %r{^[-a-z]+://} =~ source
           source = ActionController::Base.asset_host + source unless source.include?(":")
           source
         end
+        
+        def rails_asset_id(source)
+          ENV["RAILS_ASSET_ID"] || 
+            File.stat(RAILS_ROOT + "/public/#{source}").mtime.to_i.to_s
+        end
     end
   end
 end

actionpack/test/template/asset_tag_helper_test.rb

@@ -27,6 +27,11 @@ class AssetTagHelperTest < Test::Unit::TestCase
     ActionView::Helpers::AssetTagHelper::reset_javascript_include_default
   end
 
+  def teardown
+    Object.send(:remove_const, :RAILS_ROOT) if defined?(RAILS_ROOT)
+    ENV["RAILS_ASSET_ID"] = nil
+  end
+
   AutoDiscoveryToTag = {
     %(auto_discovery_link_tag) => %(<link href="http://www.example.com" rel="alternate" title="RSS" type="application/rss+xml" />),
     %(auto_discovery_link_tag(:atom)) => %(<link href="http://www.example.com" rel="alternate" title="ATOM" type="application/atom+xml" />),
@@ -115,6 +120,17 @@ class AssetTagHelperTest < Test::Unit::TestCase
     ImageLinkToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
   end
   
+  def test_timebased_asset_id
+    Object.send(:const_set, :RAILS_ROOT, File.dirname(__FILE__) + "/../fixtures/")
+    expected_time = File.stat(File.expand_path(File.dirname(__FILE__) + "/../fixtures/public/images/rails.png")).mtime.to_i.to_s
+    assert_equal %(<img alt="Rails" src="/images/rails.png?#{expected_time}" />), image_tag("rails.png")
+  end
+  
+  def test_preset_asset_id
+    Object.send(:const_set, :RAILS_ROOT, File.dirname(__FILE__) + "/../fixtures/")
+    ENV["RAILS_ASSET_ID"] = "4500"
+    assert_equal %(<img alt="Rails" src="/images/rails.png?4500" />), image_tag("rails.png")
+  end
 end
 
 class AssetTagHelperNonVhostTest < Test::Unit::TestCase