Python+Requests+Xpath实现动态参数获取实战

1、古诗文网直接登录时，用浏览器F12抓取登录接口的入参，我们可以看到框起来的key对应的value是动态参数生成的，需获取到；

 2、登录接口入参的值一般是登录接口返回的原数据值，若刷新后接口与对应源码（element）的值存在一个为空一个有值，那么久看下是否存在ajax请求，再获取动态参数的值

 3、我们获取动态参数的值，使用到etree中的xpath进行解析

from TestCase.Api_Review.ClassCode import Chaojiying_Client
from lxml import etree
import requests
import os

s = requests.Session()

# 新建文件夹
if not os.path.exists('./gushiwenLibs'):
    os.makedirs('./gushiwenLibs')
# 对验证码图片进行抓捕及识别
url = 'https://so.gushiwen.cn/user/login.aspx?from=http://so.gushiwen.cn/user/collect.aspx'
headers = {
    'User-Agent':'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.111 Safari/537.36'
}
page_text = s.get(url=url,headers=headers,proxies=None).text
tree = etree.HTML(page_text)
img_url = "https://so.gushiwen.cn/RandCode.ashx"+tree.xpath('//*[@id="imgCode"]/@src')[0]
__VIEWSTATE = tree.xpath('//*[@id="__VIEWSTATE"]/@value')[0]
__VIEWSTATEGENERATOR = tree.xpath('//*[@id="__VIEWSTATEGENERATOR"]/@value')[0]

4、登录界面的图片验证码，我们先获取对应的图形验证码，下载到本地，然后再使用第三方平台进行提取
参考此链接：Python+Request库+第三方平台实现验证码识别示例

img_src = s.get(url=img_url,headers=headers).content
# 图片存储的路径
fileName = './gushiwenLibs/'+'code_img_data.jpg'
with open(fileName, 'wb') as fp:
    fp.write(img_src)

# 使用超级鹰平台实现验证码识别
chaojiying = Chaojiying_Client('TeacherTao', 'TeacherTao', '96001')
with open(fileName, 'rb') as fp:
     img = fp.read()
result = chaojiying.PostPic(img, 1004)['pic_str']
# print(result)

5、最后再使用登录接口发起请求，我们使用Session进行登录的，因为请求头中携带Cookies进行登录了

# 登录Url
url_login = 'https://so.gushiwen.cn/user/login.aspx?from=http://so.gushiwen.cn/user/collect.aspx'
data = {
    '__VIEWSTATE': __VIEWSTATE,
    '__VIEWSTATEGENERATOR': __VIEWSTATEGENERATOR,
    'from': 'http://so.gushiwen.cn/user/collect.aspx',
    'email': '18126248212',
    'pwd': 'qqq123',
    'code': result,
    'denglu': '登录',
}

post_text = s.post(url_login,data=data,headers=headers)
# print(post_text.text)
fileName1 = './gushiwenLibs/'+'gushiren.html'
with open(fileName1, 'w',encoding='utf-8') as fp:
    fp.write(post_text.text)

6、整个项目的源码：

from TestCase.Api_Review.ClassCode import Chaojiying_Client
from lxml import etree
import requests
import os

s = requests.Session()

# 新建文件夹
if not os.path.exists('./gushiwenLibs'):
    os.makedirs('./gushiwenLibs')
# 对验证码图片进行抓捕及识别
url = 'https://so.gushiwen.cn/user/login.aspx?from=http://so.gushiwen.cn/user/collect.aspx'
headers = {
    'User-Agent':'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.111 Safari/537.36'
}
page_text = s.get(url=url,headers=headers,proxies=None).text
tree = etree.HTML(page_text)
img_url = "https://so.gushiwen.cn/RandCode.ashx"+tree.xpath('//*[@id="imgCode"]/@src')[0]
__VIEWSTATE = tree.xpath('//*[@id="__VIEWSTATE"]/@value')[0]
__VIEWSTATEGENERATOR = tree.xpath('//*[@id="__VIEWSTATEGENERATOR"]/@value')[0]
img_src = s.get(url=img_url,headers=headers).content
# 图片存储的路径
fileName = './gushiwenLibs/'+'code_img_data.jpg'
with open(fileName, 'wb') as fp:
    fp.write(img_src)

# 使用超级鹰平台实现验证码识别
chaojiying = Chaojiying_Client('TeacherTao', 'TeacherTao', '96001')
with open(fileName, 'rb') as fp:
     img = fp.read()
result = chaojiying.PostPic(img, 1004)['pic_str']
print(result)

# 登录Url
url_login = 'https://so.gushiwen.cn/user/login.aspx?from=http://so.gushiwen.cn/user/collect.aspx'
data = {
    '__VIEWSTATE': __VIEWSTATE,
    '__VIEWSTATEGENERATOR': __VIEWSTATEGENERATOR,
    'from': 'http://so.gushiwen.cn/user/collect.aspx',
    'email': '账号',
    'pwd': '密码',
    'code': result,
    'denglu': '登录',
}

post_text = s.post(url_login,data=data,headers=headers)
# print(post_text.text)
fileName1 = './gushiwenLibs/'+'gushiren.html'
with open(fileName1, 'w',encoding='utf-8') as fp:
    fp.write(post_text.text)