Prevent conflict between mime types and Object methods

Assuming the type ":touch", Collector.new was calling
send(:touch), which instead of triggering method_missing
and generating a new collector method, actually
invoked the private method `touch` inherited from
Object.

By generating the method for each mime type as it
is registered, the private methods on Object can
never be reached by `send`, because the `Collector`
will have them before `send` is called on it.

To do this, a callback mechanism was added to Mime::Type

This allows someone to add a callback for whenever
a new mime type is registered. The callback then
gets called with the new mime as a parameter.

This is then used in AbstractController::Collector
to generate new collector methods after each mime
is registered.

1 files changed, 14 insertions, 0 deletions

diff --git a/actionpack/test/dispatch/mime_type_test.rb b/actionpack/test/dispatch/mime_type_test.rb
index 9d77c3acc5..ed012093a7 100644
--- a/actionpack/test/dispatch/mime_type_test.rb
+++ b/actionpack/test/dispatch/mime_type_test.rb
@@ -118,6 +118,20 @@ class MimeTypeTest < ActiveSupport::TestCase
     end
   end
 
+  test "register callbacks" do
+    begin
+      registered_mimes = []
+      Mime::Type.register_callback do |mime|
+        registered_mimes << mime
+      end
+
+      Mime::Type.register("text/foo", :foo)
+      assert_equal registered_mimes, [Mime::FOO]
+    ensure
+      Mime::Type.unregister(:FOO)
+    end
+  end
+
   test "custom type with extension aliases" do
     begin
       Mime::Type.register "text/foobar", :foobar, [], [:foo, "bar"]