macOS系统上或首次使用Python的urllib模块时出现 ssl.SSLCertVerificationError 错误

今天在macOS系统上运行如下的Python代码时报错：

python 复制代码

from urllib.request import urlopen
from bs4 import BeautifulSoup

html = urlopen('http://www.pythonscraping.com/pages/page1.html')
bs = BeautifulSoup(html.read(), 'html.parser')
print(bs.h1)

首先我在macOS中运行pip install beautifulsoup4安装了beautifulsoup4库，并且同样的代码在Windows11上正常运行，所以代码没有什么问题，后面Google搜索了一下找到了解决方法。

报错如下：

bash 复制代码

$ python scrapetest.py
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 1319, in do_open
    h.request(req.get_method(), req.selector, req.data, headers,
    ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
              encode_chunked=req.has_header('Transfer-encoding'))
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/http/client.py", line 1338, in request
    self._send_request(method, url, body, headers, encode_chunked)
    ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/http/client.py", line 1384, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
    ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/http/client.py", line 1333, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/http/client.py", line 1093, in _send_output
    self.send(msg)
    ~~~~~~~~~^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/http/client.py", line 1037, in send
    self.connect()
    ~~~~~~~~~~~~^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/http/client.py", line 1479, in connect
    self.sock = self._context.wrap_socket(self.sock,
                ~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^
                                          server_hostname=server_hostname)
                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/ssl.py", line 455, in wrap_socket
    return self.sslsocket_class._create(
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        sock=sock,
        ^^^^^^^^^^
    ...<5 lines>...
        session=session
        ^^^^^^^^^^^^^^^
    )
    ^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/ssl.py", line 1076, in _create
    self.do_handshake()
    ~~~~~~~~~~~~~~~~~^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/ssl.py", line 1372, in do_handshake
    self._sslobj.do_handshake()
    ~~~~~~~~~~~~~~~~~~~~~~~~~^^
ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1028)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/chufengcao/WorkSpace/PythonProjects/python-scraping-demo-ccf/scrapetest.py", line 4, in <module>
    html = urlopen('http://www.pythonscraping.com/pages/page1.html')
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 189, in urlopen
    return opener.open(url, data, timeout)
           ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 495, in open
    response = meth(req, response)
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 604, in http_response
    response = self.parent.error(
        'http', request, response, code, msg, hdrs)
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 527, in error
    result = self._call_chain(*args)
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 466, in _call_chain
    result = func(*args)
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 720, in http_error_302
    return self.parent.open(new, timeout=req.timeout)
           ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 489, in open
    response = self._open(req, data)
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 506, in _open
    result = self._call_chain(self.handle_open, protocol, protocol +
                              '_open', req)
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 466, in _call_chain
    result = func(*args)
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 1367, in https_open
    return self.do_open(http.client.HTTPSConnection, req,
           ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                        context=self._context)
                        ^^^^^^^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/urllib/request.py", line 1322, in do_open
    raise URLError(err)
urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1028)>

关键错误信息为：urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1028)>

问题原因

macOS 上的 Python 可能无法访问系统默认证书。最可靠的解决方法通常是运行 Python 安装包中提供的特定脚本来安装或更新 certifi 包，该包提供了一个经过整理的根证书列表。

解决方法

1.打开终端。
2.运行以下命令（该命令专门用于 macOS 上的 Python 安装）：

bash 复制代码

/Applications/Python\ 3.13/Install\ Certificates.command

注意：如果您以不同的方式安装 Python，路径可能会略有不同。从您的回溯信息来看，路径 /Library/Frameworks/Python.framework/Versions/3.13/ 可能是 Python 的安装位置。）运行此脚本后，请再次尝试运行您的 python scrapetest.py脚本。

重新运行python scrapetest.py脚本，得到如下的结果：

bash 复制代码

<h1>An Interesting Title</h1>