如何从Django中的信号处理程序获取会话

I'm implementing a simple referral system. I have middleware which sets a session variable identifying the referring user. I have a model which ties a referring user to the referred user. I'm trying to use the post_save signal from the User object to populate this model. How do I access the session object from within the post_save signal handler?I'm implementing a simple referral system. I ha