Python爬虫之模拟登陆

import requests
from lxml import etree

class Login(object):
    def __init__(self):
        self.headers = {
            'Referer':'https://github.com',
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML,like Gecko) Chrome/57.0.2987.133 Safari/537.36',
            'Host':'github.com'
        }
        self.login_url = 'https://github.com/login'
        self.post_url = 'https://github.com/session'
        self.logined_url = 'https://github.com/settings/profile'
        self.session = requests.Session()   #维持会话

    def token(self):
        response = self.session.get(self.login_url,headers=self.headers) #访问登陆页面
        selector = etree.HTML(response.text)
        token = selector.xpath('//div/input[2]/@value')[0]  #XPath解析authenticity_token信息
        return token

    def login(self,email,password):
        post_data = {
            'commit':'Sign in',
            'utf8': '?',
            'authenticity_token': self.token(),
            'login': 'email',
            'password': password
        }