Flask
request.referrer  # 来路

request.headers.get('User-Agent')  # 请求头
Django
request.META['HTTP_REFERER']  # 来路

request.META.get("HTTP_USER_AGENT")  # 请求头

参考
http://docs.jinkan.org/docs/flask/reqcontext.html?highlight=referrer
http://www.sharejs.com/codes/python/5158