import re
import base64
headers={
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36',
#     'Connection': 'keep-alive',

}
s=requests.Session()
url='https://kyfw.12306.cn/otn/resources/login.html'
url='https://kyfw.12306.cn/passport/captcha/captcha-image64?login_site=E&module=login&rand=sjrand&1566980745733&callback=jQuery1910500591329861616_1566980496040&_=1566980496044'
s.get(url,headers=headers)
page_text=s.get(url,headers=headers).text
print(page_text)
b64_image = re.findall(r'{"image":"(.*?)",', page_text, re.S)[0]
image_data = base64.b64decode(b64_image)
with open(r"./12306.jpg", "wb") as f:
    f.write(image_data)

# tree=etree.HTML(page_text)
# src=tree.xpath('//*[@id="J-loginImg"]/@src')[0]
img_text=getCodeImgText('./12306.jpg',9004)
print('识别内容',img_text)