text: import os
  basedir = os.path.abspath(os.path.dirname(__file__))
  
  
  class Config:
      SECRET_KEY = os.environ.get('SECRET_KEY') or 'hard to guess string'
      SQLALCHEMY_COMMIT_ON_TEARDOWN = True
      MAIL_SERVER = 'smtp.qq.com'
      MAIL_PORT = 587
      MAIL_USE_TLS = True
      MAIL_USERNAME = os.environ.get('MAIL_USERNAME')
      MAIL_PASSWORD = os.environ.get('MAIL_PASSWORD')
      FLASKY_MAIL_SUBJECT_PREFIX = '[Flasky]'
      FLASKY_MAIL_SENDER = 'tonkun@vip.qq.com'
      FLASKY_ADMIN = os.environ.get('FLASKY_ADMIN')
  
      @staticmethod
      def init_app(app):
          pass
  
  
  class DevelopmentConfig(Config):
      DEBUG = True
      SQLALCHEMY_DATABASE_URI = os.environ.get('DEV_DATABASE_URL') or \
          'sqlite:///' + os.path.join(basedir, 'data-dev.sqlite')
  
  
  class TestingConfig(Config):
      TESTING = True
      SQLALCHEMY_DATABASE_URI = os.environ.get('TEST_DATABASE_URL') or \
          'sqlite:///' + os.path.join(basedir, 'data-test.sqlite')
  
  
  class ProductionConfig(Config):
      SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or \
          'sqlite:///' + os.path.join(basedir, 'data.sqlite')
  
  
  config = {
      'development': DevelopmentConfig,
      'testing': TestingConfig,
      'production': ProductionConfig,
  
      'default': DevelopmentConfig
  }
  