《图解技术体系》How do devices receive push messages?

Devices receive push messages through a process that involves several components working together. Here is a general overview of how devices receive push messages:

1. App Server: The app server is responsible for sending the push notification to the device. When there is new information or an alert to be sent to the user, the app server initiates the push notification process.

2. Push Notification Service: The push notification service is a third-party service provided by platforms like Firebase Cloud Messaging (FCM) for Android devices, Apple Push Notification Service (APNs) for iOS devices, or other similar services. The app server sends the push notification data to the push notification service.

3. Device Token: When a user installs an app on their device, the device registers with the push notification service and receives a unique device token. This token is used to identify the device and route push notifications to it.

4. Push Notification Payload: The push notification service creates a notification payload that contains the message to be displayed, any custom data, and other relevant information. This payload is sent to the device token associated with the target device.

5. Device Operating System: The device's operating system receives the push notification payload from the push notification service. The OS then processes the payload and displays the notification on the device's screen, along with any sound, vibration, or other notification actions specified in the payload.

6. User Interaction: When the user interacts with the push notification, such as tapping on it, the app associated with the notification is opened, and the user can view the full content or take action as required.

Overall, the process involves the app server sending a push notification to the push notification service, which then delivers the notification to the target device using the device token. The device operating system processes the notification and displays it to the user, allowing them to engage with the app or content as needed.