class ActionDispatch::Request

def raw_post

work with raw requests directly.
Read the request \body. This is useful for web services that need to 
def raw_post
  unless @env.include? 'RAW_POST_DATA'
    @env['RAW_POST_DATA'] = body.read(@env['CONTENT_LENGTH'].to_i)
    body.rewind if body.respond_to?(:rewind)
  end
  @env['RAW_POST_DATA']
end