Flask
request.referrer # 来路
request.headers.get('User-Agent') # 请求头
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
