Collect mimes declared in the class method respond_to valid
for the current action.
# File actionpack/lib/action_controller/metal/mime_responds.rb, line 241
def collect_mimes_from_class_level #:nodoc:
action = action_name.to_sym
self.class.mimes_for_respond_to.keys.select do |mime|
config = self.class.mimes_for_respond_to[mime]
if config[:except]
!config[:except].include?(action)
elsif config[:only]
config[:only].include?(action)
else
true
end
end
end