Push Messaging

Push Messaging is a concept in web development that delivers real-time notifications to users, keeping them updated even when the web application is not open. This feature is particularly useful for sending timely alerts, updates, or reminders directly to a user’s device, ensuring they stay informed about important events or changes. Push Messaging leverages the Service Worker API to deliver these messages, even when the application is inactive, enhancing user engagement and retention.

推送消息是在Web开发中的一个概念，它通过实时通知将更新信息传递给用户，即使Web应用程序未打开。这个功能特别适用于直接向用户设备发送及时的警报、更新或提醒，确保他们随时了解重要事件或变化。推送消息利用服务工作者API来传递这些消息，即使应用程序处于非活动状态，也能提高用户参与度和保留率。

Here’s how Push Messaging works in theory:

以下是推送消息在理论上的工作原理：

1. Subscription Request: The web application asks the user for permission to send push notifications. If the user grants permission, a subscription object is created, linking the user’s device to the push service.

   订阅请求: Web应用程序请求用户允许发送推送通知。如果用户授予权限，将创建一个订阅对象，将用户的设备与推送服务链接。

2. Message Creation and Delivery: The web server sends a push message to the push service, which then delivers the message to the user’s device through the Service Worker, even if the web application is not currently active.

   消息创建与传递: Web服务器将推送消息发送到推送服务，推送服务通过服务工作者将消息传递到用户设备，即使Web应用程序当前不活跃。

3. Notification Display: The Service Worker triggers a notification on the user’s device, alerting them to the new message. The user can interact with the notification, such as clicking it to open the application or dismissing it.

   通知显示: 服务工作者在用户设备上触发通知，提醒他们有新消息。用户可以与通知互动，例如点击打开应用程序或关闭通知。

4. User Interaction: Depending on the nature of the push message, the user may take action directly from the notification, such as replying to a message, viewing an update, or dismissing an alert.

   用户互动: 根据推送消息的性质，用户可以直接从通知中采取行动，例如回复消息、查看更新或关闭警报。

Here’s an example scenario of how Push Messaging might be implemented:

以下是推送消息可能实现的一个示例场景：

1. A user subscribes to push notifications on a news website.
2. A breaking news event occurs, and the website server sends a push message to all subscribers.
3. The user receives the push notification on their device, even though the browser is closed.
4. The user clicks the notification to read the full news article on the website.

1. 用户在新闻网站上订阅推送通知。
2. 发生重大新闻事件，网站服务器向所有订阅者发送推送消息。
3. 用户在设备上收到推送通知，即使浏览器已关闭。
4. 用户点击通知以阅读网站上的完整新闻文章。

The comparison of Push Messaging with other notification methods is shown in the table below:

推送消息与其他通知方法的比较如下表所示：

Push Messaging is very useful for keeping users engaged by delivering timely and relevant updates directly to their devices, ensuring they stay informed and connected even when the application is not actively in use.

推送消息通过直接将及时和相关的更新传递到用户的设备，确保他们随时了解情况并保持连接，即使应用程序未被积极使用，也非常有助于保持用户参与度。

以下是关于推送消息的5个面试问题及其答案

1. What is Push Messaging, and how does it benefit web applications?

什么是推送消息，它对Web应用程序有何好处？

Push Messaging is a feature that delivers real-time notifications to users, even when the web application is not open, helping to keep users informed and engaged with timely updates.

推送消息是一种功能，它可以在Web应用程序未打开时向用户发送实时通知，帮助用户及时了解信息并保持参与。

2. How does Push Messaging differ from in-app notifications?

推送消息与应用内通知有何不同？

Push Messaging delivers notifications even when the application is not open, while in-app notifications are only sent while the application is active and the user is interacting with it.

推送消息即使在应用程序未打开时也能传递通知，而应用内通知仅在应用程序活跃且用户与其互动时发送。

3. What are the key steps to implement Push Messaging in a web application?

在Web应用程序中实现推送消息的关键步骤是什么？

Key steps include requesting user permission, subscribing the user to push notifications, creating and sending push messages from the server, and displaying notifications through the Service Worker.

关键步骤包括请求用户权限、订阅用户推送通知、从服务器创建和发送推送消息以及通过服务工作者显示通知。

4. How can users interact with Push Messaging notifications?

用户如何与推送消息通知互动？

Users can interact with Push Messaging notifications by clicking to open the application, viewing the content, dismissing the notification, or taking specific actions like replying to a message.

用户可以通过点击打开应用程序、查看内容、关闭通知或采取特定操作（如回复消息）与推送消息通知进行互动。

5. What are some common use cases for Push Messaging?

推送消息的一些常见用例是什么？

Common use cases include sending breaking news alerts, notifying users of new messages or updates, reminding users of upcoming events, or alerting them to important account activities.

常见的用例包括发送突发新闻警报、通知用户新消息或更新、提醒用户即将发生的事件或提醒他们重要的账户活动。

Recommended Resources:

1. MDN Web Docs: Push API
2. Google Developers: Web Push Notifications