Remove #size call on rack input io

actionpack/lib/action_dispatch/middleware/params_parser.rb

@@ -36,17 +36,13 @@ def parse_formatted_parameters(env)
         when Proc
           strategy.call(request.raw_post)
         when :xml_simple, :xml_node
-          request.body.size == 0 ? {} : Hash.from_xml(request.raw_post).with_indifferent_access
+          (Hash.from_xml(request.raw_post) || {}).with_indifferent_access
         when :yaml
           YAML.load(request.raw_post)
         when :json
-          if request.body.size == 0
-            {}
-          else
-            data = ActiveSupport::JSON.decode(request.raw_post)
-            data = {:_json => data} unless data.is_a?(Hash)
-            data.with_indifferent_access
-          end
+          data = ActiveSupport::JSON.decode(request.raw_post)
+          data = {:_json => data} unless data.is_a?(Hash)
+          data.with_indifferent_access
         else
           false
         end