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 has_header? "RAW_POST_DATA"
    raw_post_body = body
    set_header("RAW_POST_DATA", raw_post_body.read(content_length))
    raw_post_body.rewind if raw_post_body.respond_to?(:rewind)
  end
  get_header "RAW_POST_DATA"
end