https://scrapingclub.com/exercise/detail_sign/

    def parse(self, response):
        # pattern1 = re.compile('token=(.*?);')
        # token = pattern1.findall(response.headers.getlist("set-cookie")[1].decode("utf-8"))[0]

        pattern2 = re.compile('token=(.*?);')
        token = pattern2.findall(response.headers.getlist("set-cookie")[1].decode("utf-8"))[0]
        token_md5= token.encode("utf-8")
        sign= hashlib.md5(token_md5).hexdigest()
        cookie = {
            'token': token,
        }
        url='https://scrapingclub.com/exercise/ajaxdetail_sign/?sign='+sign
        yield scrapy.Request(url= url,cookies=cookie,headers=header,callback=self.parse_json)

关键在于把token转成MD5

def get_md(url):
    m = hashlib.md5()
    m.update(url)
    return m.hexdigest()
copy from: https://www.jianshu.com/p/271b20f7574f

用到了其中的两句，不知道为什么要update，其中就像原作者说的，不能直接hashlib.md5(str)必须是byte，需要转码一次