Python爬虫 —— 知乎之selenium模拟登陆获取cookies+requests.Session()访问+session序列化

代码如下：

 # coding:utf-8
 from selenium import webdriver
 import requests
 import sys
 import time
 from lxml import etree
 import cPickle
 import os
 # reload(sys)
 # sys.setdefaultencoding('utf-8')

 class Zhihu:
     def __init__(self,homeurl):
         self.homeurl = homeurl

     def save_session(self,session): #保存session，下次可直接使用，避免再次登录
         with open('session.txt','wb') as f:
             cPickle.dump(session, f)
             print "Cookies have been writed."

     def load_session(self):     #加载session
         with open('session.txt', 'rb') as f:
             s = cPickle.load(f)
         return s

     def GetCookies(self):       #初次登录用selenium模拟，并获得cookies
         browser = webdriver.Chrome()
         browser.get("https://www.zhihu.com/signin")
         browser.find_element_by_xpath("//main//div[2]/div[1]/form/div[1]/div[2]/div[1]/input").send_keys("")
         browser.find_element_by_xpath("//main//div[2]/div[1]/form/div[2]/div/div[1]/input").send_keys("xxxxxx")
         browser.find_element_by_xpath("//main//div[2]/div[1]/form/button").click()
         time.sleep(10)
         cookies = browser.get_cookies()
         browser.quit()
         return cookies

     def get_session(self):  #获取session
         s = requests.Session()
         if not os.path.exists('session.txt'):   #如果没有session，则创建一个，并且保存到文件中
             s.headers.clear()
             for cookie in self.GetCookies():
                 s.cookies.set(cookie['name'], cookie['value'])
             self.save_session(s)
         else:                                   #如果已存在session，则直接加载使用
             s = self.load_session()
         return s

     def Crawl(self):    #开始爬取
         s = self.get_session()
         html = s.get(self.homeurl).text
         html_tree = etree.HTML(html)
         items = html_tree.xpath('//main//div[1]/div[2]//div[@class="ContentItem AnswerItem"]/@data-zop')
         for item in items:
             content = eval(item)
             authorName = content['authorName']
             title = content['title']
             print authorName + "回答了：" + title

 zhihu = Zhihu('https://www.zhihu.com/')
 zhihu.Crawl()