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python - 使用 Python 'requests' 库的 HTTPS POST 请求出现不一致的 IOError 异常

问题描述

尝试使用 HTTPS POST 时，我不断收到以下异常requests

此问题偶尔会发生，并且在重试（使用backoff模块）成功通过时相同的请求。我不知道如何重现此问题，但当我运行大量 HTTPS POST 请求时会看到此问题。

Traceback (most recent call last):
 File \"/usr/local/lib/python2.7/dist-packages/shared/util/http_util.py\", line 71, in send_https_post_request
 response = session.post(url, cert=cert, data=data)
 File \"/usr/local/lib/python2.7/dist-packages/requests/sessions.py\", line 522, in post
 return self.request('POST', url, data=data, json=json, **kwargs)
 File \"/usr/local/lib/python2.7/dist-packages/requests/sessions.py\", line 475, in request
 resp = self.send(prep, **send_kwargs)
 File \"/usr/local/lib/python2.7/dist-packages/requests/sessions.py\", line 596, in send
 r = adapter.send(request, **kwargs)
 File \"/usr/local/lib/python2.7/dist-packages/requests/adapters.py\", line 423, in send
 timeout=timeout
 File \"/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/connectionpool.py\", line 595, in urlopen
 chunked=chunked)
 File \"/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/connectionpool.py\", line 352, in _make_request
 self._validate_conn(conn)
 File \"/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/connectionpool.py\", line 831, in _validate_conn
 conn.connect()
 File \"/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/connection.py\", line 289, in connect
 ssl_version=resolved_ssl_version)
 File \"/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/util/ssl_.py\", line 306, in ssl_wrap_socket
 context.load_cert_chain(certfile, keyfile)
IOError: [Errno 2] No such file or directory

相关代码：

@contextlib.contextmanager
def pem_bytes_as_cert_file(pem_cert_bytes):
    '''
     Given bytes, return a temporary file which can be used as the cert
    '''
    with tempfile.NamedTemporaryFile(delete=True, suffix='.pem') as t_pem:
        f_pem = open(t_pem.name, 'wb')
        f_pem.write(pem_cert_bytes)
        f_pem.close()
        yield t_pem.name

def send_https_post_request(session, url, data, pem_cert_in_bytes):
    with pem_bytes_as_cert_file(pem_cert_in_bytes) as cert:
        response = session.post(url, cert=cert, data=data)
        response.raise_for_status()
        response.close()

你能帮我更多地了解这个问题吗？

标签： pythonsslpython-requestsurllib3

解决方案

... context.load_cert_chain(certfile, keyfile)
IOError: [Errno 2] No such file or directory

上下文显然是在加载证书和密钥

with pem_bytes_as_cert_file(pem_cert_in_bytes) as cert:
    response = session.post(url, cert=cert, data=data)

您似乎将证书和密钥作为字符串并尝试创建一个临时文件以将其作为cert参数

with tempfile.NamedTemporaryFile(delete=True, suffix='.pem') as t_pem:
    f_pem = open(t_pem.name, 'wb')
    f_pem.write(pem_cert_bytes)
    f_pem.close()
    yield t_pem.name

您创建一个临时文件tempfile.NamedTemporaryFile并将 cert+key 字符串写入其中。然后关闭临时文件。NamedTemporaryFile的文档指出：

如果 delete 为 true（默认值），则文件一关闭就会被删除。

因此，一旦您关闭该文件，该文件就会被删除。仅当您很幸运（竞争条件）时，当您尝试从内部使用该文件时，该文件仍然可以在系统中访问session.post。

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