FLASK网址(https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-i-hello-world)
Chapter 1: Hello, World!
运行
$ flask run
报错
WARNING: Do not use the development server in a production environment.
Use a production WSGI server instead.
解决方法:先运行
$ export FLASK_ENV=development
或将 FLASK_ENV=development 写入.flaskenv,再
$ flask run
即可