如何将消息发送到Android中的主题 [英] How to send message to the topic in Android

问题描述

如何通过Firebase发送主题消息？

我只使用Firebase Console，
以及Post方式HTTP请求，
，但我不明白如何在Android中执行。

如何在Android
中编写一些代码要指定一个主题，然后发送一个消息到主题？

谢谢。

服务器密钥的HTTP调用。顾名思义，这个关键只能用在你可以信任的环境中。您不能直接从设备发送消息到其他设备，包括主题。 Firebase云消息传递文档中的这个

所以如果你想发送消息从一个Android应用程序，您将不得不：

1. 创建Android应用程序所对应的服务器端代码


2. 具有该服务器端代码
   
   

   您会看到这个示例中的方法与博客文章中的方法非常相似：都侦听数据库写入来触发发送FCM消息。示例中的一些更改与博客文章相比：示例用 b
   
   

   
   
   • https://github.com/firebase/functions-samples/blob/master/fcm-notifications/functions/index.js#L28rel =noreferrer>云端功能。 noreferrer>发送到设备令牌而不是主题。
   
   
   • 示例使用新的 Firebase Admin SDK 至发送消息，而不是调用FCM HTTP端点
   
   
   
   

   How to send a topic message via Firebase ?

   I only found the way to send by using Firebase Console , as well as some ways about Post HTTP requests , but I don't understand how to do it in Android.

   How can I write some codes in Android to specify a topic which to target then send a message to the topic?

   Thanks.

   解决方案

   Sending a message to devices (so-called downstream messages) requires a HTTP call that specifies the server key. As its name implies, this key should only be used in environments you can trust. You cannot directly send a message from a device to other devices, including topics. This diagram from the Firebase Cloud Messaging documentation shows the flow:

   So if you want to send messages from an Android app, you will have to:

   1. create server-side code that the Android app talks to
   2. have that server-side code call Firebase Cloud Messaging to send messages
   3. have the Android app call your server-side code

   One way to accomplish such a flow is described in our blog post Sending notifications between Android devices with Firebase Database and Cloud Messaging. It uses the Firebase Database to communicate with a server-side script that then calls FCM to send the messages to topics. The server-side code in this post is a Node.js script, since it was the simplest approach available when I wrote it.

   But last week Firebase released Cloud Functions for Firebase. This allows you to run server-side code without managing your own infrastructure, which makes it a perfect fit for your use-case. In fact it is such a good fit that it's first in the documentation on use-cases for Cloud Functions for Firebase:

   You will see that the approach in this sample is very similar to the one in the blog post: both listen for database writes to trigger sending FCM messages. Some of the changes in the sample compared to the blog post:

   • the sample replaces the Node.js script with a Cloud Function.
   • the sample sends to device tokens instead of topics.
   • the sample uses the new Firebase Admin SDK to send messages, instead of calling the FCM HTTP end-point

   这篇关于如何将消息发送到Android中的主题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！