python爬虫---爬取优信二手车

import requests
import re
import redis
from lxml import etree
import pymysql
#获取城市数据
class City():
    def __init__(self):
        #初始化Redis连接
        self.r=self.get_redis()
    def __call__(self, *args, **kwargs):
        self.get_city()
    # 创建数据库，减少对网站的攻击
    def get_redis(self):
        return redis.Redis(host='127.0.0.1', port=6379, db=1)
    def get_city(self):
        # 初始的url
        interface_url="https://www.xin.com/apis/Ajax_common/get_home_city/"
        import json
        json_data=str(requests.get(interface_url).json())
        print(json_data)
        print(type(json_data))
        #获取城市：
        city_name=re.findall("'ename': '(.*?)'",json_data)
        # print(city_name)
        #遍历城市，获取城市的url
        for city in city_name:
            city_url="https://www.xin.com/{}/s/?channel=a49b117c44837d110753e751863f53".format(city)
            # print('================正在下载{}=============='.format(city))
            # print(city_url)
            #将城市的链接写入Redis数据库
            self.r.rpush("city_url", city_url)
    def get_html(self,url):
        response=requests.get(url)
        html=response.text
        # print(html)
        return  html,etree.HTML(html)
# 获取所有车的品牌：
class AutomobileBrand(City):
    def __call__(self, *args, **kwargs):
        self.get_brand()
    def get_brand(self):
        city_url_all=self.r.lrange('city_url',0,-1)
        # print(city_url_all)
        for city_url in city_url_all:
            # 根据url获取所有的车的品牌：
            # print(city_url.decode('utf-8'))
            htnl,html_xml=self.get_html(city_url.decode('utf-8'))
            car_brand_name=html_xml.xpath('//ul//li[position()>1]/dl/dd/a/text()')
            car_brand_url=html_xml.xpath('//ul//li[position()>1]/dl/dd/a/@href')
            # print(car_brand_url)
            # print(car_brand_name)
            for index in range(len(car_brand_url)):