adds #favicon_link_tag back, rdoc explains why it is useful, and how to get a link for Mobile Safari with it

2 files changed, 46 insertions, 0 deletions

diff --git a/actionpack/lib/action_view/helpers/asset_tag_helper.rb b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
index e4ec17467e..85401ad561 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
@@ -501,6 +501,40 @@ module ActionView
         end
       end
 
+      # Web browsers cache favicons. If you just throw a <tt>favicon.ico</tt> into the document
+      # root of your application and it changes later, clients that have it in their cache
+      # won't see the update. Using this helper prevents that because it appends an asset ID:
+      #
+      #   <%= favicon_link_tag %>
+      #
+      # generates
+      #
+      #   <link href="/favicon.ico?4649789979" rel="shortcut icon" type="image/vnd.microsoft.icon" />
+      #
+      # You may specify a different file in the first argument:
+      #
+      #   <%= favicon_link_tag 'favicon.ico' %>
+      #
+      # That's passed to +image_path+ as is, so it gives
+      #
+      #   <link href="/images/favicon.ico?4649789979" rel="shortcut icon" type="image/vnd.microsoft.icon" />
+      #
+      # The helper accepts an additional options hash where you can override "rel" and "type".
+      #
+      # For example, Mobile Safari looks for a different LINK tag, pointing to an image that
+      # will be used if you add the page to the home screen of an iPod Touch, iPhone, or iPad.
+      # The following call would generate such a tag:
+      #
+      #   <%= favicon_link_tag 'mb-icon.png', :rel => 'apple-touch-icon', :type => 'image/png' %>
+      #
+      def favicon_link_tag(source='/favicon.ico', options={})
+        tag('link', {
+          :rel  => 'shortcut icon',
+          :type => 'image/vnd.microsoft.icon',
+          :href => image_path(source)
+        }.merge(options.symbolize_keys))
+      end
+
       # Computes the path to an image asset in the public images directory.
       # Full paths from the document root will be passed through.
       # Used internally by +image_tag+ to build the image path.
diff --git a/actionpack/test/template/asset_tag_helper_test.rb b/actionpack/test/template/asset_tag_helper_test.rb
index 223a430f92..124bf734ac 100644
--- a/actionpack/test/template/asset_tag_helper_test.rb
+++ b/actionpack/test/template/asset_tag_helper_test.rb
@@ -157,6 +157,14 @@ class AssetTagHelperTest < ActionView::TestCase
     %(image_tag("mouse.png", :mouseover => image_path("mouse_over.png"))) => %(<img alt="Mouse" onmouseover="this.src='/images/mouse_over.png'" onmouseout="this.src='/images/mouse.png'" src="/images/mouse.png" />)
   }
 
+  FaviconLinkToTag = {
+    %(favicon_link_tag) => %(<link href="/favicon.ico" rel="shortcut icon" type="image/vnd.microsoft.icon" />),
+    %(favicon_link_tag 'favicon.ico') => %(<link href="/images/favicon.ico" rel="shortcut icon" type="image/vnd.microsoft.icon" />),
+    %(favicon_link_tag 'favicon.ico', :rel => 'foo') => %(<link href="/images/favicon.ico" rel="foo" type="image/vnd.microsoft.icon" />),
+    %(favicon_link_tag 'favicon.ico', :rel => 'foo', :type => 'bar') => %(<link href="/images/favicon.ico" rel="foo" type="bar" />),
+    %(favicon_link_tag 'mb-icon.png', :rel => 'apple-touch-icon', :type => 'image/png') => %(<link href="/images/mb-icon.png" rel="apple-touch-icon" type="image/png" />)
+  }
+
   VideoPathToTag = {
     %(video_path("xml"))          => %(/videos/xml),
     %(video_path("xml.ogg"))      => %(/videos/xml.ogg),
@@ -331,6 +339,10 @@ class AssetTagHelperTest < ActionView::TestCase
     ImageLinkToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
   end
 
+  def test_favicon_link_tag
+    FaviconLinkToTag.each { |method, tag| assert_dom_equal(tag, eval(method)) }
+  end
+
   def test_image_tag_windows_behaviour
     old_asset_id, ENV["RAILS_ASSET_ID"] = ENV["RAILS_ASSET_ID"], "1"
     # This simulates the behaviour of File#exist? on windows when testing a file ending in "."