python使用requests时报错requests.exceptions.SSLError: HTTPSConnectionPool

python使用requests时报错requests.exceptions.SSLError: HTTPSConnectionPool

 

报错信息

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\api.py", line 72, in get
return request('get', url, params=params, **kwargs)
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\api.py", line 58, in request
return session.request(method=method, url=url, **kwargs)
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\sessions.py", line 508, in request
resp = self.send(prep, **send_kwargs)
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\sessions.py", line 640, in send
history = [resp for resp in gen] if allow_redirects else []
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\sessions.py", line 218, in resolve_redirects
**adapter_kwargs
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\sessions.py", line 618, in send
r = adapter.send(request, **kwargs)
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\adapters.py", line 506, in send
raise SSLError(e, request=request)
requests.exceptions.SSLError: HTTPSConnectionPool(host= 'www.baidu.com', port=443): Max retries exceeded with url: / (Caused by SSLError(SSLError(1, u'[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:581)'),))

过程

测试1

不指定headers时GET:

>>> import requests
>>> requests.get('http://www.baidu.com/')
<Response [ 200]>
>>> requests.get('http://www.baidu.com/')
<Response [ 200]>
>>> requests.get('http://www.baidu.com/')
<Response [ 200]>
>>> header = {'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.1',}
>>> requests.get('http://www.baidu.com/', headers = header)
<Response [ 200]>

测试2

当指定headers的User-Agent为火狐浏览器时:

>>> header = {'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.1',}
>>> requests.get('http://www.baidu.com/', headers = header)
<Response [ 200]>
>>> requests.get('http://www.baidu.com/', headers = header)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\api.py", line 72, in get
return request('get', url, params=params, **kwargs)
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\api.py", line 58, in request
return session.request(method=method, url=url, **kwargs)
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\sessions.py", line 508, in request
resp = self.send(prep, **send_kwargs)
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\sessions.py", line 640, in send
history = [resp for resp in gen] if allow_redirects else []
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\sessions.py", line 218, in resolve_redirects
**adapter_kwargs
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\sessions.py", line 618, in send
r = adapter.send(request, **kwargs)
File "D:\python\lib\site-packages\requests-2.18.3-py2.7.egg\requests\adapters.py", line 506, in send
raise SSLError(e, request=request)
requests.exceptions.SSLError: HTTPSConnectionPool(host= 'www.baidu.com', port=443): Max retries exceeded with url: / (Caused by SSLError(SSLError(1, u'[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:581)'),))

分析

现象:第一次GET时正常,第二次GET时,会报错.

不同点:User-Agent不相同

分析:由于报错SSL证书验证失败,所以这次的访问应该是https协议.但是我们明明使用的是http,所以,猜测访问该网站后,被重定向到了https://www.baidu.com/

验证

首先,进行GET时,关闭证书验证.因为,如果不关闭,请求总是失败,不能获取到重定向的信息.

>>> response = requests.get('http://www.baidu.com/', headers = header, verify=False)
D:\python\lib\site-packages\urllib3\connectionpool.py: 858: InsecureRequestWarning: Unverified HTTPS request is being made. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#ssl-warnings
InsecureRequestWarning)
>>> response.history
[<Response [ 302]>]
>>> response.url
u'https://www.baidu.com/'

当不指定User-Agent时

>>> response = requests.get('http://www.baidu.com/', verify=False)
>>> response.history
[]
>>> response.url
u'http://www.baidu.com/'

结论

当指定headers的User-Agent时,baidu的服务器会重定向到https的网址.因此报出SSL验证失败的错误.

解决方法

方法1:

在进行GET时,指定SSL证书.详情见附件

方法2:

关闭证书验证. 详情见附件

附件

[各浏览器的User-Agent] http://www.useragentstring.com/pages/useragentstring.php

[SSL 证书验证] http://docs.python-requests.org/zh_CN/latest/user/advanced.html#ssl