Flask-Security-Too 异步邮件发送的重构与通用解决方案

from flask_mail import Mail
from flask import Flask

mail = Mail()
# security = None # 假设 security 对象已在其他地方初始化

def create_app(test_config=None):
    app = Flask(__name__)
    # ... 配置 app 和 Flask-Security-Too ...
    mail.init_app(app)
    # global security # 示例中假设 security 是全局的或已传入
    # security = Security(app, user_datastore) # 示例初始化

    # 已弃用的装饰器用法示例
    # @security.send_mail_task
    # def delay_security_email(msg):
    #     with app.app_context():
    #         send_security_email(msg)

    def send_security_email(msg):
        # 使用 Flask-Mail 扩展实例发送传入的 `msg` 参数
        with app.app_context():
            mail.send(msg)

    return app

import threading
from functools import wraps

def async_action(fn):
    """
    一个通用装饰器，用于在单独的线程中异步执行函数。
    """
    @wraps(fn)
    def wrapped(*args, **kwargs):
        # 创建一个新线程来执行目标函数
        thread = threading.Thread(target=fn, args=args, kwargs=kwargs)
        thread.start() # 启动线程
    return wrapped

from flask import Flask
from flask_mail import Mail, Message
# from flask_security_too import Security, SQLAlchemySessionUserDatastore # 示例导入
import threading
from functools import wraps

# 自定义的异步装饰器
def async_action(fn):
    @wraps(fn)
    def wrapped(*args, **kwargs):
        thread = threading.Thread(target=fn, args=args, kwargs=kwargs)
        thread.start()
    return wrapped

# 邮件发送函数，现在使用我们自定义的异步装饰器
@async_action
def send_security_email_async(app_context, msg):
    """
    异步发送安全相关邮件。
    需要传入 app_context 以便在新线程中正确获取 Flask 应用上下文。
    """
    with app_context:
        mail.send(msg)

# Flask-Mail 实例（全局或通过 create_app 初始化）
mail = Mail()

def create_app():
    app = Flask(__name__)
    app.config.update(
        SECRET_KEY='a_very_secret_key', # 用于 Flask-Security-Too 或其他安全功能
        MAIL_SERVER='smtp.example.com',
        MAIL_PORT=587,
        MAIL_USE_TLS=True,
        MAIL_USERNAME='your_email@example.com',
        MAIL_PASSWORD='your_password',
        MAIL_DEFAULT_SENDER='your_email@example.com'
    )
    # ... 其他 Flask 和 Flask-Security-Too 配置 ...

    mail.init_app(app)
    # security.init_app(app, user_datastore) # 示例初始化

    @app.route('/')
    def index():
        return "Hello, Flask App! Visit /send_test_email to send an async email."

    @app.route('/send_test_email')
    def send_test_email():
        msg = Message("Hello from Flask",
                      sender="your_email@example.com",
                      recipients=["recipient@example.com"])
        msg.body = "This is a test email sent asynchronously using a custom decorator."

        # 在主线程中获取应用上下文，并传递给异步函数
        # app.app_context() 返回一个上下文管理器，我们需要获取其内部的 app_context 栈
        # 或者直接传递 app 实例，让异步函数自行创建上下文
        # 推荐传递 app 实例，这样异步函数可以自行管理上下文的生命周期
        send_security_email_async(app.app_context(), msg) 

        return "Test email sent asynchronously! Check your recipient's inbox."

    return app

if __name__ == '__main__':
    app = create_app()
    app.run(debug=True)