Action Pack Variants

By default, variants in the templates will be picked up if a variant is set
and there's a match. The format will be:

  app/views/projects/show.html.erb
  app/views/projects/show.html+tablet.erb
  app/views/projects/show.html+phone.erb

If request.variant = :tablet is set, we'll automatically be rendering the
html+tablet template.

In the controller, we can also tailer to the variants with this syntax:

  class ProjectsController < ActionController::Base
    def show
      respond_to do |format|
        format.html do |html|
          @stars = @project.stars

          html.tablet { @notifications = @project.notifications }
          html.phone  { @chat_heads    = @project.chat_heads }
        end

        format.js
        format.atom
      end
    end
  end

The variant itself is nil by default, but can be set in before filters, like
so:

  class ApplicationController < ActionController::Base
    before_action do
      if request.user_agent =~ /iPad/
        request.variant = :tablet
      end
    end
  end

This is modeled loosely on custom mime types, but it's specifically not
intended to be used together. If you're going to make a custom mime type,
you don't need a variant. Variants are for variations on a single mime
types.

1 files changed, 54 insertions, 0 deletions

diff --git a/actionpack/test/controller/mime/respond_to_test.rb b/actionpack/test/controller/mime/respond_to_test.rb
index 774dabe105..2b6c8739af 100644
--- a/actionpack/test/controller/mime/respond_to_test.rb
+++ b/actionpack/test/controller/mime/respond_to_test.rb
@@ -146,6 +146,26 @@ class RespondToController < ActionController::Base
     end
   end
 
+  def variant_with_implicit_rendering
+  end
+
+  def variant_with_format_and_custom_render
+    request.variant = :mobile
+
+    respond_to do |type|
+      type.html { render text: "mobile" }
+    end
+  end
+
+  def multiple_variants_for_format
+    respond_to do |type|
+      type.html do |html|
+        html.tablet { render text: "tablet" }
+        html.phone  { render text: "phone" }
+      end
+    end
+  end
+
   protected
     def set_layout
       case action_name
@@ -490,4 +510,38 @@ class RespondToControllerTest < ActionController::TestCase
       get :using_defaults, :format => "invalidformat"
     end
   end
+
+  def test_invalid_variant
+    @request.variant = :invalid
+    assert_raises(ActionView::MissingTemplate) do
+      get :variant_with_implicit_rendering
+    end
+  end
+
+  def test_variant_not_set_regular_template_missing
+    assert_raises(ActionView::MissingTemplate) do
+      get :variant_with_implicit_rendering
+    end
+  end
+
+  def test_variant_with_implicit_rendering
+    @request.variant = :mobile
+    get :variant_with_implicit_rendering
+    assert_equal "text/html", @response.content_type
+    assert_equal "mobile", @response.body
+  end
+
+  def test_variant_with_format_and_custom_render
+    @request.variant = :phone
+    get :variant_with_format_and_custom_render
+    assert_equal "text/html", @response.content_type
+    assert_equal "mobile", @response.body
+  end
+
+  def test_multiple_variants_for_format
+    @request.variant = :tablet
+    get :multiple_variants_for_format
+    assert_equal "text/html", @response.content_type
+    assert_equal "tablet", @response.body
+  end
 end