Use `Mime[:foo]` instead of `Mime::Type[:FOO]` for back compat

Rails 4.x and earlier didn't support `Mime::Type[:FOO]`, so libraries
that support multiple Rails versions would've had to feature-detect
whether to use `Mime::Type[:FOO]` or `Mime::FOO`.

`Mime[:foo]` has been around for ages to look up registered MIME types
by symbol / extension, though, so libraries and plugins can safely
switch to that without breaking backward- or forward-compatibility.

Note: `Mime::ALL` isn't a real MIME type and isn't registered for lookup
by type or extension, so it's not available as `Mime[:all]`. We use it
internally as a wildcard for `respond_to` negotiation. If you use this
internal constant, continue to reference it with `Mime::ALL`.

Ref. efc6dd550ee49e7e443f9d72785caa0f240def53

1 files changed, 4 insertions, 9 deletions

diff --git a/actionpack/lib/abstract_controller/collector.rb b/actionpack/lib/abstract_controller/collector.rb
index 3b5128cda5..55654be224 100644
--- a/actionpack/lib/abstract_controller/collector.rb
+++ b/actionpack/lib/abstract_controller/collector.rb
@@ -4,11 +4,10 @@ module AbstractController
   module Collector
     def self.generate_method_for_mime(mime)
       sym = mime.is_a?(Symbol) ? mime : mime.to_sym
-      const = sym.upcase
       class_eval <<-RUBY, __FILE__, __LINE__ + 1
-        def #{sym}(*args, &block)                # def html(*args, &block)
-          custom(Mime::Type[:#{const}], *args, &block)  #   custom(Mime::Type[:HTML], *args, &block)
-        end                                      # end
+        def #{sym}(*args, &block)
+          custom(Mime[:#{sym}], *args, &block)
+        end
       RUBY
     end
 
@@ -23,9 +22,7 @@ module AbstractController
   protected
 
     def method_missing(symbol, &block)
-      const_name = symbol.upcase
-
-      unless Mime::Type.registered?(const_name)
+      unless mime_constant = Mime[symbol]
         raise NoMethodError, "To respond to a custom format, register it as a MIME type first: " \
           "http://guides.rubyonrails.org/action_controller_overview.html#restful-downloads. " \
           "If you meant to respond to a variant like :tablet or :phone, not a custom format, " \
@@ -33,8 +30,6 @@ module AbstractController
           "format.html { |html| html.tablet { ... } }"
       end
 
-      mime_constant = Mime::Type[const_name]
-
       if Mime::SET.include?(mime_constant)
         AbstractController::Collector.generate_method_for_mime(mime_constant)
         send(symbol, &block)