关闭应用程序时监听 Firebase 数据库的变化 [英] Listen to firebase database changes when app is closed

问题描述

我正在创建一个带有 firebase 的 Ionic 2 应用程序，当应用程序关闭(即在前台、后台和被杀死)时，我需要一种方法来监听数据库更改(特别是在 child_ added 上)

I am creating an Ionic 2 app with firebase and I need a way to listen to database changes (specifically on child_added) when the app is closed (I.e. in foreground,background and killed)

基本上，我想使用 WebRTC 在应用程序内拨打电话，例如 whatsapp，我正在关注这篇文章 - https://websitebeaver.com/insanely-simple-webrtc-video-chat-using-firebase-with-codepen-demo

Basically, I want to use WebRTC to make calls within the app like whatsapp and I am following this post - https://websitebeaver.com/insanely-simple-webrtc-video-chat-using-firebase-with-codepen-demo

然而，唯一让我感到困惑的是当应用程序关闭时它会如何工作.谁能帮我理解一下?

However, the only thing that puzzles me is how it will work when the app is closed. Can anyone please help me understand?

谢谢！

推荐答案

使用 Firebase 客户端 SDK 无法以与应用代码运行时完全相同的方式主动监听数据库更改.

It's not possible to actively listen to database changes using the Firebase client SDK in exactly the same way that you can when your app's code is running.

如果您希望您的应用接收有关数据库更改的信息，您可以改为使用 Firebase Cloud Messaging 向您的应用发送带有包含更改信息的小负载的通知.当您的应用收到通知时，它可以决定要做什么.网络支持有一些限制，因此请务必阅读

If you want your app to receive information about changes to your database, you can instead use Firebase Cloud Messaging to send your app a notification with a small payload that contains information about the change. When your app receives the notification, it can then make a decision about what to do. There are some limitations with web support, so be sure to read about that.

同时查看 Cloud Functions for Firebase 以便更轻松地编写一些服务器端可以触发以响应数据库更改并在发生这些更改时发送通知的代码.

Also look into Cloud Functions for Firebase to make it easier to write some server side code that can trigger in response to a database change and send a notification when those changes happen.

这篇关于关闭应用程序时监听 Firebase 数据库的变化的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！