code: async def identify(self, request):
          
          if hasattr(request, '_session_identity'):
              return request._session_identity
  
          token = request.cookies.get(self._cookie_name)
          if token is None:
              token = getAuthorizationTokenFromHeader(request)
              if token is None:
                  raise Unauthorized('无认证身份')
  
          identity = await self.decode_jwt(token)
          setattr(request, '_session_identity', identity)
  
          # if identity.client_id.startsWith('spa|'):
          #     checkCRSFToken(request)
  
          return identity
docs: 从request中得到登录身份identity