python爬虫headers设置后无效的解决方法
时间：2020-11-06 23:40:59 | 栏目：Python代码 | 点击：次
此次遇到的是一个函数使用不熟练造成的问题，但有了分析工具后可以很快定位到问题（此处推荐一个非常棒的抓包工具fiddler）
正文如下：
在爬取某个app数据时（app上的数据都是由http请求的），用Fidder分析了请求信息，并把python的request header信息写在程序中进行请求数据
代码如下
import requests
url = 'http://xxx?startDate=2017-10-19&endDate=2017-10-19&pageIndex=1&limit=50&sort=datetime&order=desc'
headers={
"Host":"xxx.com",
"Connection": "keep-alive",
"Accept": "application/json, text/javascript, */*; q=0.01",
"User-Agent": "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.59 Safari/537.36",
"X-Requested-With": "XMLHttpRequest",
"Referer": "http://app.jg.eastmoney.com/html_Report/index.html",
"Accept-Encoding": "gzip,deflate",
"Accept-Language": "en-us,en",
"Cookie":"xxx"
}
r = requests.get(url,headers)
print (r.text)
请求成功但是，返回的是
{"Id":"6202c187-2fad-46e8-b4c6-b72ac8de0142","ReturnMsg":"加载失败！"}
就是被发现不是正常请求被拦截了
然后我去Fidder中看刚才python发送请求的记录 #盖掉的两个部分分别是Host和URL。
然后查看请求详细信息的时候，请求头并没有加载进去，User-Agent就写着python-requests ! #请求头里的UA信息是java，python程序，有点反爬虫意识的网站、app都会拦截掉
Header详细信息如下
GET http://xxx?istartDate=2017-10-19&endDate=2017-10-19&pageIndex=1&limit=50&sort=datetime&order=desc &Host=xxx.com &Connection=keep-alive &Accept=application%2Fjson%2C+text%2Fjavascript%2C+%2A%2F%2A%3B+q%3D0.01 &User-Agent=Mozilla%2F5.0+%28Windows+NT+6.1%3B+WOW64%29+AppleWebKit%2F537.36+%28KHTML%2C+like+Gecko%29+Chrome%2F29.0.1547.59+Safari%2F537.36 &X-Requested-With=XMLHttpRequest &Referer=xxx &Accept-Encoding=gzip%2Cdeflate &Accept-Language=en-us%2Cen &Cookie=xxx HTTP/1.1 Host: xxx.com User-Agent: python-requests/2.18.4 Accept-Encoding: gzip, deflate Accept: */* Connection: keep-alive HTTP/1.1 200 OK Server: nginx/1.2.2 Date: Sat, 21 Oct 2017 06:07:21 GMT Content-Type: application/json; charset=utf-8 Content-Length: 75 Connection: keep-alive Cache-Control: private X-AspNetMvc-Version: 5.2 X-AspNet-Version: 4.0.30319 X-Powered-By: ASP.NET
一开始还没发现，等我把请求的URL信息全部读完，才发现程序把我的请求头信息当做参数放到了URL里
那就是我请求的时候request函数Header信息参数用错了
又重新看了一下Requests库的Headers参数使用方法，发现有一行代码写错了，在使用request.get（）方法时要把参数 “headers =“写出来
更改如下：
import requests
url = 'http://xxx?startDate=2017-10-19&endDate=2017-10-19&pageIndex=1&limit=50&sort=datetime&order=desc'
headers={
"Host":"xxx.com",
"Connection": "keep-alive",
"Accept": "application/json, text/javascript, */*; q=0.01",
"User-Agent": "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.59 Safari/537.36",
"X-Requested-With": "XMLHttpRequest",
"Referer": "http://app.jg.eastmoney.com/html_Report/index.html",
"Accept-Encoding": "gzip,deflate",
"Accept-Language": "en-us,en",
"Cookie":"xxx"
}
r = requests.get(url,headers=headers)
然后去查看Fiddler中的请求。
此次python中的请求头已经正常了，请求详细信息如下
GET http://xxx?startDate=2017-10-19&endDate=2017-10-19&pageIndex=1&limit=50&sort=datetime&order=desc HTTP/1.1 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.59 Safari/537.36 Accept-Encoding: gzip,deflate Accept: application/json, text/javascript, */*; q=0.01 Connection: keep-alive Host: xxx.com X-Requested-With: XMLHttpRequest Referer: http://xxx Accept-Language: en-us,en Cookie: xxx HTTP/1.1 200 OK Server: nginx/1.2.2 Date: Sat, 21 Oct 2017 06:42:21 GMT Content-Type: application/json; charset=utf-8 Content-Length: 75 Connection: keep-alive Cache-Control: private X-AspNetMvc-Version: 5.2 X-AspNet-Version: 4.0.30319 X-Powered-By: ASP.NET
然后又用python程序请求了一次，结果请求成功，返回的还是
{"Id":"6202c187-2fad-46e8-b4c6-b72ac8de0142","ReturnMsg":"加载失败！"}
因为一般cookie都会在短时间内过期，所以更新了cookie，然后请求成功
需要注意的是用程序爬虫一定要把Header设置好，这个app如果反爬的时候封ip的话可能就麻烦了。