当模块已经安装时，获取烧瓶失败导入烧瓶-mysqldb的错误

Question

我正在尝试从 this 教程中学习将烧瓶与 MySQL 数据库链接。

我使用 pip3 将flask-mysqldb 安装到我的虚拟环境中，这很成功。

有一些答案，但在我的情况下它们都涵盖了fail to install flask-mysqldb，安装本身是成功的，但我仍然在网页上收到错误。

当我使用 flask run 启动服务器并尝试在浏览器中运行路由 URL localhost:5000/ 时，我收到 flask-mysqldb 的导入错误。

这是我得到的确切错误：

flask.cli.NoAppException: While importing "todo_app", an ImportError was raised:

File "/home/shubham/venv/lib/python3.6/site-packages/flask/cli.py", line 240, in locate_app
__import__(module_name)

File "/home/shubham/repos/academy-hackathon/week-0/day-3/my_todo_app/todo_app/app.py", line 7, in <module> 
from flask_mysqldb import MySQL 

File "/home/shubham/venv/lib/python3.6/site-packages/flask_mysqldb/__init__.py", line 1, in <module> 
import MySQLdb 

File "/home/shubham/venv/lib/python3.6/site-packages/MySQLdb/__init__.py", line 18, in <module> 
from . import _mysql 

ImportError: libmysqlclient.so.18: cannot open shared object file: No such file or directory

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/shubham/venv/lib/python3.6/site-packages/flask/cli.py", line 338, in __call__
    self._flush_bg_loading_exception()
  File "/home/shubham/venv/lib/python3.6/site-packages/flask/cli.py", line 326, in _flush_bg_loading_exception
    reraise(*exc_info)
  File "/home/shubham/venv/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/home/shubham/venv/lib/python3.6/site-packages/flask/cli.py", line 314, in _load_app
    self._load_unlocked()
  File "/home/shubham/venv/lib/python3.6/site-packages/flask/cli.py", line 330, in _load_unlocked
    self._app = rv = self.loader()
  File "/home/shubham/venv/lib/python3.6/site-packages/flask/cli.py", line 388, in load_app
    app = locate_app(self, import_name, name)
  File "/home/shubham/venv/lib/python3.6/site-packages/flask/cli.py", line 247, in locate_app
    "\n\n{tb}".format(name=module_name, tb=traceback.format_exc())
flask.cli.NoAppException: While importing "app", an ImportError was raised:

Traceback (most recent call last):
  File "/home/shubham/venv/lib/python3.6/site-packages/flask/cli.py", line 240, in locate_app
    __import__(module_name)
  File "/home/shubham/repos/academy-hackathon/week-0/day-3/my_todo_app/todo_app/app.py", line 7, in <module>
    from flask_mysqldb import MySQL
  File "/home/shubham/venv/lib/python3.6/site-packages/flask_mysqldb/__init__.py", line 1, in <module>
    import MySQLdb
  File "/home/shubham/venv/lib/python3.6/site-packages/MySQLdb/__init__.py", line 18, in <module>
    from . import _mysql
ImportError: libmysqlclient.so.18: cannot open shared object file: No such file or directory

venv是python环境的名字

我不确定为什么会出现此错误，我正在从安装模块 flask-mysqldb 的同一 python 环境运行服务器。

另外，我在“base”命名环境的机器上安装了 anaconda-navigator，我尝试使用 conda install flask-mysqldb 安装模块，但没有显示模块错误。那么这个错误有可能是conda环境造成的吗？

请提出任何解决方案，从昨晚开始就一直坚持这个。

编辑： 我发现here 安装MySQL-python 应该可以解决这个问题，但我在安装MySQL-python 时遇到另一个错误

Collecting MySQL-python
  Using cached https://files.pythonhosted.org/packages/a5/e9/51b544da85a36a68debe7a7091f068d802fc515a3a202652828c73453cad/MySQL-python-1.2.5.zip
    ERROR: Complete output from command python setup.py egg_info:
    ERROR: Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-install-9zyrtdz5/MySQL-python/setup.py", line 13, in <module>
        from setup_posix import get_config
      File "/tmp/pip-install-9zyrtdz5/MySQL-python/setup_posix.py", line 2, in <module>
        from ConfigParser import SafeConfigParser
    ModuleNotFoundError: No module named 'ConfigParser'
    ----------------------------------------
ERROR: Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-install-9zyrtdz5/MySQL-python/

Answer 1

首先，安装Flask-MySQLdb：

$ pip install flask-mysqldb

Flask-MySQLdb 依赖并将为您安装最新版本的 Flask（0.12.4 或更高版本）和 mysqlclient。 Flask-MySQLdb 与 Python 2.7、3.5、3.6 和 3.7 兼容并经过测试。

接下来，将 MySQL 实例添加到您的代码中：

from flask import Flask
from flask_mysqldb import MySQL

..根据提供的信息 - here.

文档链接 - here。

Answer 2

按同样的顺序试试这个

sudo apt install python3.6-dev libpython3.6-dev
sudo apt-get install mysql-server
virtualenv -p python3.6 venv
source venv/bin/activate
pip3 install flask
pip3 install flask-mysqldb

然后创建app.py

from flask import Flask

app = Flask(__name__)


if __name__ == '__main__':
    app.run()

然后执行应用模块

python app.py