爬虫中如何获取图片验证码

1.采用网站截图方式

import requests
import time

from selenium import webdriver
from PIL import Image


def part_screenshot(driver):
    driver.save_screenshot("hello1.png")
    return Image.open("hello1.png")


def get_image(driver):  # 对验证码所在位置进行定位，然后截取验证码图片
    img = driver.find_element_by_xpath('//*[@id="u1"]/a[2]')
    time.sleep(2)
    location = img.location
    print(location, 111)
    size = img.size
    left = location['x']
    top = location['y']
    right = left + size['width']
    bottom = top + size['height']
    page_snap_obj = part_screenshot(driver)
    image_obj = page_snap_obj.crop((left, top, right, bottom))
    return image_obj  # 得到的就是验证码


if __name__ == '__main__':
    driver = webdriver.Chrome()
    driver.get("https://www.baidu.com")
    print(driver.title)  # 打印页面的标题
    b = get_image(driver)
    b.save("1.png")
    print(b)
    driver.quit()  # 一定要退出！不退出会有残留进程！

2.采用cookie获取图片验证码

原理：浏览器请求图片验证码时，有些网页将图片的验证码编号信息存储到cookie中，用户提交登陆时，只提交图片验证码的值即可。后端通过cookie验证图片验证码编号是否正确。
class Yun00Da1ma():
    def __init__(self):
        self.session=requests.session()
        self.headers={
            "Referer":"http://www.×××.com/",
            "User-Agent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.102 Safari/537.36"

        }


    def get_picture(self):
        url="http://www.×××.com/index/captcha"
        resp = self.session.get(url, headers=self.headers)#请求图片时，服务器会返回图片，并添加图片信息到session
        with open("dama.png","wb") as f:
            f.write(resp.content)
        img_result=check_img("dama.png")
        url1="http://www.×××.com/index/login?username=×××&password=×××&utype=ajh&vcode="+img_result
        resp2=self.session.get(url1,headers=self.headers)#进行模拟登陆
        # print(resp2.content.decode("gbk","ignore"),11)


    def get_user(self):#采用session保持，直接登陆用户界面，验证是否登陆成功
        url="http://www.×××.com/user"
        resp2 = self.session.get(url, headers=self.headers)
        

if __name__ == '__main__':
   yun00da1ma=Yun00Da1ma()
   yun00da1ma.get_picture()
   yun00da1ma.get_user()