A XML parameters parser for Action Pack (removed from core in Rails 4.0)

Include this gem into your Gemfile:

gem 'actionpack-xml_parser', github: 'rails/actionpack-xml_parser'

Then, add ActionDispatch::XmlParamsParser middleware after ActionDispatch::ParamsParser in config/application.rb:

config.middleware.insert_after ActionDispatch::ParamsParser, ActionDispatch::XmlParamsParser