Merge pull request #14043 from strzalek/variants-negotiation

Variant negotiation

actionpack/lib/action_controller/metal/mime_responds.rb

@@ -236,6 +236,18 @@ def clear_respond_to
     #     end
     #   end
     #
+    # You can also set an array of variants:
+    #
+    #   request.variant = [:tablet, :phone]
+    #
+    # which will work similarly to formats and MIME types negotiation. If there will be no
+    # :tablet variant declared, :phone variant will be picked:
+    #
+    #   respond_to do |format|
+    #     format.html.none
+    #     format.html.phone # this gets rendered
+    #   end
+    #
     # Be sure to check the documentation of +respond_with+ and
     # <tt>ActionController::MimeResponds.respond_to</tt> for more examples.
     def respond_to(*mimes, &block)
@@ -488,7 +500,7 @@ def response
           response
         else # `format.html{ |variant| variant.phone }` - variant block syntax
           variant_collector = VariantCollector.new(@variant)
-          response.call(variant_collector) #call format block with variants collector
+          response.call(variant_collector) # call format block with variants collector
           variant_collector.variant
         end
       end
@@ -519,15 +531,15 @@ def method_missing(name, *args, &block)
         end
 
         def variant
-          key = if @variant.nil?
-            :none
-          elsif @variants.has_key?(@variant)
-            @variant
+          if @variant.nil?
+            @variants[:none]
+          elsif (@variants.keys & @variant).any?
+            @variant.each do |v|
+              return @variants[v] if @variants.key?(v)
+            end
           else
-            :any
+            @variants[:any]
           end
-
-          @variants[key]
         end
       end
     end

actionpack/lib/action_dispatch/http/mime_negotiation.rb

@@ -68,10 +68,12 @@ def formats
 
       # Sets the \variant for template.
       def variant=(variant)
-        if variant.is_a? Symbol
+        if variant.is_a?(Symbol)
+          @variant = [variant]
+        elsif variant.is_a?(Array)
           @variant = variant
         else
-          raise ArgumentError, "request.variant must be set to a Symbol, not a #{variant.class}. " \
+          raise ArgumentError, "request.variant must be set to a Symbol or Array, not a #{variant.class}. " \
             "For security reasons, never directly set the variant to a user-provided value, " \
             "like params[:variant].to_sym. Check user-provided value against a whitelist first, " \
             "then set the variant: request.variant = :tablet if params[:variant] == 'tablet'"

actionpack/test/controller/mime/respond_to_test.rb

@@ -740,4 +740,25 @@ def test_format_any_variant_any
     assert_equal "text/javascript", @response.content_type
     assert_equal "tablet", @response.body
   end
+
+  def test_variant_negotiation_inline_syntax
+    @request.variant = [:tablet, :phone]
+    get :variant_inline_syntax_without_block
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+  end
+
+  def test_variant_negotiation_block_syntax
+    @request.variant = [:tablet, :phone]
+    get :variant_plus_none_for_format
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+  end
+
+  def test_variant_negotiation_without_block
+    @request.variant = [:tablet, :phone]
+    get :variant_inline_syntax_without_block
+    assert_equal "text/html", @response.content_type
+    assert_equal "phone", @response.body
+  end
 end

actionpack/test/dispatch/request_test.rb

@@ -846,8 +846,12 @@ def url_for(options = {})
 
   test "setting variant" do
     request = stub_request
+
     request.variant = :mobile
-    assert_equal :mobile, request.variant
+    assert_equal [:mobile], request.variant
+
+    request.variant = [:phone, :tablet]
+    assert_equal [:phone, :tablet], request.variant
   end
 
   test "setting variant with non symbol value" do

actionview/lib/action_view/rendering.rb

@@ -94,7 +94,7 @@ def _render_template(options) #:nodoc:
         variant = options[:variant]
 
         lookup_context.rendered_format = nil if options[:formats]
-        lookup_context.variants = [variant] if variant
+        lookup_context.variants = variant if variant
 
         view_renderer.render(view_context, options)
       end