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'
    raw_post_body = body
    @env['RAW_POST_DATA'] = raw_post_body.read(content_length)
    raw_post_body.rewind if raw_post_body.respond_to?(:rewind)
  end
  @env['RAW_POST_DATA']
end