Requests爬取百度搜索页面，只要带param参数就返回百度安全验证，不带参数就能成功

Question

记一次疑问：在使用requests库爬取百度搜索关键字结果页面时，使用完整关键字url就能返回成功，若使用param参数将关键字加载在get（）内即返回百度安全验证页面，爬取失败。具体是什么原因？

问题相关代码，请勿粘贴截图

使用完整url，可爬取成功代码：

-- coding:utf-8 --

import requests
if name =="main":
headers = {
'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,/;q=0.8,application/signed-exchange;v=b3;q=0.9',
'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.51 Safari/537.36'
}

keyword = input("enter a  word:")
url = 'https://www.baidu.com/s?'+'wd='+keyword
response = requests.get(url=url , headers=headers)
response.encoding='utf-8'
page_text = response.text
filename = 'python.html'
with open(filename,'w',encoding='utf-8') as fp:
    fp.write(page_text)
    print(filename,"保存成功！！")

使用param参数，返回失败代码：

-- coding:utf-8 --

import requests
if name =="main":
headers = {
'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,/;q=0.8,application/signed-exchange;v=b3;q=0.9',
'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.51 Safari/537.36'
}

kw = input("enter a  word:")
param ={
    'param':kw
}
url = 'https://www.baidu.com/s?wd'
response = requests.get(url=url ,params=param, headers=headers)
response.encoding='utf-8'
page_text = response.text
filename = 'python.html'
with open(filename,'w',encoding='utf-8') as fp:
    fp.write(page_text)
    print(filename,"保存成功！！")

失败结果：

分别尝试过使用param和未使用param，结果不一样。但是搜狗不论加不加param都可以访问。加了Accept仍然没用，区别就在requests.get（）里面，不知道具体原因是什么。

想知道到底是为啥，百度用的反爬是啥逻辑

Answer 1

关键字键名称搞错了，是wd，不是param

import requests

headers = {
'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,/;q=0.8,application/signed-exchange;v=b3;q=0.9',
'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.51 Safari/537.36'
}

kw = input("enter a  word:")
param ={
    'wd':kw
}
url = 'https://www.baidu.com/s'
response = requests.get(url=url ,params=param, headers=headers)
response.encoding='utf-8'
page_text = response.text
filename = 'python.html'
with open(filename,'w',encoding='utf-8') as fp:
    fp.write(page_text)
    print(filename,"保存成功！！")