重构Flask-Security-Too异步邮件发送：使用自定义线程装饰器

from flask_mail import Mail
from flask_security import Security # 假设 security 实例已创建并传入 app

mail = Mail()

def create_app(test_config=None):
    app = Flask(__name__)
    # ... Flask 应用配置 ...
    mail.init_app(app)
    security = Security(app, user_datastore) # 假设 user_datastore 已定义
    # Deprecated decorator usage
    @security.send_mail_task # 此装饰器已废弃
    def delay_security_email(msg):
        with app.app_context():
            send_security_email(msg)

    def send_security_email(msg):
        # Use the Flask-Mail extension instance to send the incoming `msg` parameter
        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。
    它支持任意数量的位置参数和关键字参数。
    """
    @wraps(fn)
    def wrapped(*args, **kwargs):
        # 创建并启动一个新线程来执行被装饰的函数
        thread = threading.Thread(target=fn, args=args, kwargs=kwargs)
        thread.start()
    return wrapped

from flask import Flask
from flask_mail import Mail, Message
from flask_security import Security, SQLAlchemySessionUserDatastore # 假设你正在使用SQLAlchemy

# 假设 app, mail, security 实例已在 create_app 中初始化
# mail = Mail()
# security = Security()

# 示例：创建 Flask 应用和相关实例
app = Flask(__name__)
app.config['MAIL_SERVER'] = 'smtp.example.com'
app.config['MAIL_PORT'] = 587
app.config['MAIL_USE_TLS'] = True
app.config['MAIL_USERNAME'] = 'your-email@example.com'
app.config['MAIL_PASSWORD'] = 'your-password'
app.config['SECURITY_REGISTERABLE'] = True
app.config['SECURITY_PASSWORD_SALT'] = 'a_very_secret_salt' # 生产环境请使用更复杂的盐
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///:memory:' # 示例数据库

mail.init_app(app)

# 假设你有一个用户模型和 SQLAlchemy 会话
# from your_models import User, db_session
# user_datastore = SQLAlchemySessionUserDatastore(db_session, User)
# security = Security(app, user_datastore)


# 自定义异步装饰器
import threading
from functools import wraps

def async_action(fn):
    @wraps(fn)
    def wrapped(*args, **kwargs):
        thread = threading.Thread(target=fn, args=args, kwargs=kwargs)
        thread.start()
    return wrapped

# 异步发送邮件函数
@async_action
def send_security_email(msg):
    """
    在单独的线程中发送 Flask-Mail 消息。
    必须在 app_context 中执行。
    """
    # 确保在独立的线程中，Flask 应用上下文是激活的
    with app.app_context(): # 这里的 app 需要是全局可访问或通过某种方式传入
        try:
            mail.send(msg)
            print(f"邮件已发送: {msg.subject}")
        except Exception as e:
            print(f"邮件发送失败: {e}")
            # 生产环境中应记录更详细的错误日志

# 将异步邮件发送函数配置到 Flask-Security-Too
# Flask-Security-Too 允许你通过 SECURITY_SEND_MAIL_TASK 配置项指定发送邮件的函数
# 或者直接通过 Security 实例的 send_mail_task 属性设置
# 示例：在应用初始化时设置
# security.send_mail_task = send_security_email # 这种方式通常用于直接替换
# 或者在 Flask-Security-Too 的配置中：
# app.config['SECURITY_SEND_MAIL_TASK'] = 'your_module.send_security_email'
# 如果 Flask-Security-Too 内部直接调用 send_mail_task，它会调用我们这个异步函数。

# 示例用法 (假设在某个视图函数或注册流程中):
def register_user_example(email, password):
    # ... 用户注册逻辑 ...
    # 假设 Flask-Security-Too 内部会调用配置的 send_mail_task
    # 或者你需要手动构造 Message 对象并调用
    with app.app_context():
        msg = Message("欢迎注册",
                      sender=app.config['MAIL_USERNAME'],
                      recipients=[email],
                      body="感谢您的注册！")
        send_security_email(msg) # 直接调用，它会在新线程中执行