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.

2 files changed, 8 insertions, 3 deletions

diff --git a/actionview/test/template/lookup_context_test.rb b/actionview/test/template/lookup_context_test.rb
index a6a3d6279e..ce9485e146 100644
--- a/actionview/test/template/lookup_context_test.rb
+++ b/actionview/test/template/lookup_context_test.rb
@@ -36,6 +36,11 @@ class LookupContextTest < ActiveSupport::TestCase
     assert @lookup_context.formats.frozen?
   end
 
+  test "provides getters and setters for variants" do
+    @lookup_context.variants = [:mobile]
+    assert_equal [:mobile], @lookup_context.variants
+  end
+
   test "provides getters and setters for formats" do
     @lookup_context.formats = [:html]
     assert_equal [:html], @lookup_context.formats
@@ -254,7 +259,7 @@ class TestMissingTemplate < ActiveSupport::TestCase
 
   test "if a single prefix is passed as a string and the lookup fails, MissingTemplate accepts it" do
     e = assert_raise ActionView::MissingTemplate do
-      details = {:handlers=>[], :formats=>[], :locale=>[]}
+      details = {:handlers=>[], :formats=>[], :variants=>[], :locale=>[]}
       @lookup_context.view_paths.find("foo", "parent", true, details)
     end
     assert_match %r{Missing partial parent/_foo with .* Searched in:\n  \* "/Path/to/views"\n}, e.message
diff --git a/actionview/test/template/testing/fixture_resolver_test.rb b/actionview/test/template/testing/fixture_resolver_test.rb
index 9649f349cb..d6cfa997cd 100644
--- a/actionview/test/template/testing/fixture_resolver_test.rb
+++ b/actionview/test/template/testing/fixture_resolver_test.rb
@@ -3,13 +3,13 @@ require 'abstract_unit'
 class FixtureResolverTest < ActiveSupport::TestCase
   def test_should_return_empty_list_for_unknown_path
     resolver = ActionView::FixtureResolver.new()
-    templates = resolver.find_all("path", "arbitrary", false, {:locale => [], :formats => [:html], :handlers => []})
+    templates = resolver.find_all("path", "arbitrary", false, {:locale => [], :formats => [:html], :variants => [], :handlers => []})
     assert_equal [], templates, "expected an empty list of templates"
   end
 
   def test_should_return_template_for_declared_path
     resolver = ActionView::FixtureResolver.new("arbitrary/path.erb" => "this text")
-    templates = resolver.find_all("path", "arbitrary", false, {:locale => [], :formats => [:html], :handlers => [:erb]})
+    templates = resolver.find_all("path", "arbitrary", false, {:locale => [], :formats => [:html], :variants => [], :handlers => [:erb]})
     assert_equal 1, templates.size, "expected one template"
     assert_equal "this text",      templates.first.source
     assert_equal "arbitrary/path", templates.first.virtual_path