无法从cryptography.hazmat.bindings._openssl加载ffi库

Question

我正在尝试在Windows 10上使用anaconda（python 3.7 64 bit）和pymysql包打开mysql数据库。

在Windows命令提示符下，我执行以下操作：

import pymysql
db = pymysql.connect(host='localhost', user='tester', passwd='xxxx', port=3306, db='mydb')

用户名，密码和端口正确；主机应该是本地主机（如果我通过127.0.0.1，则会收到相同的错误）；但我收到以下错误，最后指出无法找到ffi软件包：

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\programs\Anaconda3\lib\site-packages\pymysql\__init__.py", line 94, in Connect
    return Connection(*args, **kwargs)
  File "C:\programs\Anaconda3\lib\site-packages\pymysql\connections.py", line 327, in __init__
    self.connect()
  File "C:\programs\Anaconda3\lib\site-packages\pymysql\connections.py", line 598, in connect
    self._request_authentication()
  File "C:\programs\Anaconda3\lib\site-packages\pymysql\connections.py", line 873, in _request_authentication
    auth_packet = _auth.caching_sha2_password_auth(self, auth_packet)
  File "C:\programs\Anaconda3\lib\site-packages\pymysql\_auth.py", line 252, in caching_sha2_password_auth
    data = sha2_rsa_encrypt(conn.password, conn.salt, conn.server_public_key)
  File "C:\programs\Anaconda3\lib\site-packages\pymysql\_auth.py", line 132, in sha2_rsa_encrypt
    rsa_key = serialization.load_pem_public_key(public_key, default_backend())
  File "C:\programs\Anaconda3\lib\site-packages\cryptography\hazmat\backends\__init__.py", line 15, in default_backend
    from cryptography.hazmat.backends.openssl.backend import backend
  File "C:\programs\Anaconda3\lib\site-packages\cryptography\hazmat\backends\openssl\__init__.py", line 7, in <module>
    from cryptography.hazmat.backends.openssl.backend import backend
  File "C:\programs\Anaconda3\lib\site-packages\cryptography\hazmat\backends\openssl\backend.py", line 53, in <module>
    from cryptography.hazmat.bindings.openssl import binding
  File "C:\programs\Anaconda3\lib\site-packages\cryptography\hazmat\bindings\openssl\binding.py", line 13, in <module>
    from cryptography.hazmat.bindings._openssl import ffi, lib
ImportError: DLL load failed: The specified module could not be found.

我已经看到conda导航器（也不是pip）在其标准频道中没有看到ffi软件包。

我已经尝试过这个建议（添加conda-forge频道）：

conda配置-添加通道conda-forge conda安装libffi

但是conda永远都在“解决环境”中，并且没有在合理的时间内给出答案。

我应该怎么做才能安装ffi并能够连接到数据库？我是世界上第一个在Windows上从python / Anaconda调用mysql的人吗？我想必须有一个解决方案。

谢谢，Marco

Answer 1

我遇到了同样的问题。这是为我解决的问题： 1. pip uninstall scrapy 2. conda uninstall scrapy 3. pip install --force --upgrade scrapy 4. scrapy startproject dingding 有效。