python - "' 连接 ' object has no attribute ' _sftp_live '"当 pysftp 连接失败

Question

当“找不到主机 *** 的主机 key ”时，我想很好地捕获错误并向最终用户提供适当的消息。我试过这个:

import pysftp, paramiko
try: 
    with pysftp.Connection('1.2.3.4', username='root', password='') as sftp:
        sftp.listdir()
except paramiko.ssh_exception.SSHException as e:
    print('SSH error, you need to add the public key of your remote in your local known_hosts file first.', e)

但不幸的是输出不是很好:

SSH error, you need to add the public key of your remote in your local known_hosts file first. No hostkey for host 1.2.3.4 found.
Exception ignored in: <function Connection.__del__ at 0x00000000036B6D38>
Traceback (most recent call last):
  File "C:\Python37\lib\site-packages\pysftp\__init__.py", line 1013, in __del__
    self.close()
  File "C:\Python37\lib\site-packages\pysftp\__init__.py", line 784, in close
    if self._sftp_live:
AttributeError: 'Connection' object has no attribute '_sftp_live'

如何使用 try: except: 很好地避免这些最后几行/这个“忽略异常” ?

Answer 1

@reverse_engineer 的分析是正确的。然而:

好像多了一个属性，self._transport ，也定义为时已晚。

通过子类化 pysftp.Connection 可以暂时更正该问题，直到永久修复出现。类如下:

import pysftp
import paramiko


class My_Connection(pysftp.Connection):
    def __init__(self, *args, **kwargs):
        self._sftp_live = False
        self._transport = None
        super().__init__(*args, **kwargs)

try: 
    with My_Connection('1.2.3.4', username='root', password='') as sftp:
        l = sftp.listdir()
        print(l)
except paramiko.ssh_exception.SSHException as e:
    print('SSH error, you need to add the public key of your remote in your local known_hosts file first.', e)

更新
我无法在桌面上复制此错误。但是，我在 pysftp 的来源中看到在它初始化其 _cnopts 的代码中属性与 self._cnopts = cnopts or CnOpts()哪里 cnopts是 pysftp.Connection 的关键字参数构造函数，并且有可能是 CnOpts构造函数抛出 HostKeysException如果未找到主机 key 导致 _cnopts 的异常未设置属性。
尝试以下更新的代码，让我知道它是否有效:

import pysftp
import paramiko

class My_Connection(pysftp.Connection):
    def __init__(self, *args, **kwargs):
        try:
            if kwargs.get('cnopts') is None:
                kwargs['cnopts'] = pysftp.CnOpts()
        except pysftp.HostKeysException as e:
            self._init_error = True
            raise paramiko.ssh_exception.SSHException(str(e))
        else:
            self._init_error = False

        self._sftp_live = False
        self._transport = None
        super().__init__(*args, **kwargs)

    def __del__(self):
        if not self._init_error:
            self.close()

try:
    with My_Connection('1.2.3.4', username='root', password='') as sftp:
        l = sftp.listdir()
        print(l)
except paramiko.ssh_exception.SSHException as e:
    print('SSH error, you need to add the public key of your remote in your local known_hosts file first.', e)