Django-Celery sends activation email asynchronously

Celery sends activation email asynchronously

Introduction to Celery

• 1.Celery introduction
  • Click to view Celery reference documentation
  • Celery is a fully functional plug-and-play task queue
  • Celery is suitable for asynchronous processing problems, such as sending emails, file uploading, image processing and other time-consuming operations. We can execute them asynchronously, so that users do not need to wait for a long time, improving user experience

• 2.Celery Features:
  • Simple, easy to use and maintain, with extensive documentation
  • Efficient, a single Celery process can handle millions of tasks per minute
  • Flexible, almost every part in Celery can be custom extended
  • Celery is very easy to integrate into some web development frameworks

• 3. Install Celery

  # 进入虚拟环境
  pip install celery
  

• 4.Celery composition structure

  • A task queue is a mechanism for working across threads and machines
  • The unit of work that contains the task in the task queue. There is a dedicated worker process that continuously monitors the task queue and obtains new tasks from it and processes them
  • Celery communicates through messages, usually using a broker (middleman) to coordinate client (task issuer) and worker (task handler)
  • The client sends a message to the queue, and the broker dispatches the information in the queue to the worker for processing
  • A Celery system can contain many workers and brokers, which can enhance horizontal scalability and high availability performance.

  • The structure of Celery is an embodiment of the producer-consumer model

Celery uses

1. Create a Celery asynchronous task file

2. Create application object/client/client

• The application object internally encapsulates the tasks to be executed asynchronously
• Celery()：
  • Parameter 1 is the asynchronous task path
  • Parameter 2 is the specified broker
    • redis://password@redis ip:port/database
    • redis://192.168.243.191:6379/4
  • Returns the client application object app
• send_active_email(): Internally encapsulates the content of the activation email and registers it with the decorator @app.task

• Call python's send_mail() to send the activation email

    from celery import Celery
    from django.core.mail import send_mail
    from django.conf import settings
  
    # 创建celery应用对象
    app = Celery('celery_tasks.tasks', broker='redis://192.168.243.191:6379/4')
  
    @app.task
    def send_active_email(to_email, user_name, token):
        """发送激活邮件"""
  
        subject = "天天生鲜用户激活"  # 标题
        body = ""  # 文本邮件体
        sender = settings.EMAIL_FROM  # 发件人
        receiver = [to_email]  # 接收人
        html_body = '<h1>尊敬的用户 %s, 感谢您注册天天生鲜！</h1>' \
                    '<br/><p>请点击此链接激活您的帐号<a href="http://127.0.0.1:8000/users/active/%s">' \
                    'http://127.0.0.1:8000/users/active/%s</a></p>' %(user_name, token, token)
        send_mail(subject, body, sender, receiver, html_message=html_body)
  

3. Broker

• Example: Redis database as middleman broker is demonstrated here
• Celery needs a way to send and receive messages. We call this middleware for storing messages a message broker, or a message middleman.

• As an intermediary, we have several options:

  • 1.RabbitMQ

    • RabbitMQ is a full-featured, stable and easy-to-install broker. It is the best choice for production environments.

    • For details on using RabbitMQ refer to the following link:  http://docs.celeryproject.org/en/latest/getting-started/brokers/rabbitmq.html#broker-rabbitmq

    • If you are using an Ubuntu or Debian distribution of Linux, you can install RabbitMQ directly with the command: sudo apt-get install rabbitmq-server

    • After installation, the RabbitMQ-server server is already running in the background.
    • If you are not using Ubuntu or Debian, you can go to the following website:  http://www.rabbitmq.com/download.html to find the version software you need.

  • 2. Redis

    • Redis is also a full-featured broker option, but it is more likely to lose data due to unexpected outages or power failures.
    • Regarding which Redis is used as the Broker, you can visit the following URL:  http://docs.celeryproject.org/en/latest/getting-started/brokers/redis.html#broker-redis

4. Create worker

• Example: Here is a demonstration of creating a worker into a ubuntu virtual machine, with ubuntu as the Celery server

• Celery server create worker steps

  • 1. Copy the project code to the ubuntu virtual machine

    • and add the following code at the top of the celery_tasks/tasks.py file

    • Role: enable Celery's workers to load the Django configuration environment

      import os 
      os.environ["DJANGO_SETTINGS_MODULE"] = "dailyfresh.settings"
      # 放到Celery服务器上时添加的代码
      import django
      django.setup()
      

  • 2. The terminal creates a worker

      celery -A celery_tasks.tasks worker -l info
    

  • 3. Open redis-server and view the broker

  • 4. Test sending emails

  • 5. View the asynchronous task messages received by the worker

Complete registration logic implementation code

class RegisterView(View):
    """类视图：处理注册"""

    def get(self, request):
        """处理GET请求，返回注册页面"""
        return render(request, 'register.html')

    def post(self, request):
        """处理POST请求，实现注册逻辑"""

        # 获取注册请求参数
        user_name = request.POST.get('user_name')
        password = request.POST.get('pwd')
        email = request.POST.get('email')
        allow = request.POST.get('allow')

        # 参数校验：缺少任意一个参数，就不要在继续执行
        if not all([user_name, password, email]):
            return redirect(reverse('users:register'))
        # 判断邮箱
        if not re.match(r"^[a-z0-9][\w\.\-]*@[a-z0-9\-]+(\.[a-z]{2,5}){1,2}$", email):
            return render(request, 'register.html', {'errmsg':'邮箱格式不正确'})
        # 判断是否勾选协
        if allow != 'on':
            return render(request, 'register.html', {'errmsg': '没有勾选用户协议'})

        # 保存数据到数据库
        try:
            # 隐私信息需要加密，可以直接使用django提供的用户认证系统完成
            user = User.objects.create_user(user_name, email, password)
        except db.IntegrityError:
            return render(request, 'register.html', {'errmsg': '用户已注册'})

        # 手动的将用户认证系统默认的激活状态is_active设置成False,默认是True
        user.is_active = False
        # 保存数据到数据库
        user.save()

        # 生成激活token
        token = user.generate_active_token()

        # celery发送激活邮件：异步完成，发送邮件不会阻塞结果的返回
        send_active_email.delay(email, user_name, token)

        # 返回结果：比如重定向到首页
        return redirect(reverse('goods:index'))

#发送邮件的驱动
EMAIL_BACKEND = 'django.core.mail.backends.smtp.EmailBackend'
#邮件服务器
EMAIL_HOST = 'smtp.163.com'
#smtp服务器的端口
EMAIL_PORT = 25
#发送邮件的邮箱
EMAIL_HOST_USER = '[email protected]'
#在邮箱中设置的客户端授权密码
EMAIL_HOST_PASSWORD = 'xxxxxxxxxxx'
#收件人看到的发件人
EMAIL_FROM = '标题<[email protected]>'

Register a user to test whether the activation email is sent correctly