问题
Sending notification when a child is added in Message node
Whenever new child is added in Message node all the users should get message like"You have new message".I don't know much about node.js so I want cloud function that will send notification.
回答1:
You will find hereafter links to tutorials or code examples covering your needs. (Update: I also copied the entire code of the first example, which is an official Firebase sample).
https://firebase.google.com/docs/functions/use-cases#notify_users_when_something_interesting_happens
https://github.com/firebase/functions-samples/blob/master/developer-motivator/functions/index.js
https://android.jlelse.eu/serverless-notifications-with-cloud-functions-for-firebase-685d7c327cd4
UPDATE: Following the comment, I paste below the source from the first example (which is an official Firebase sample).
Sending the notification is done using the Firebase Admin SDK. The Web client writes the individual device tokens to the realtime database which the Function uses to send the notification.
The dependencies are listed in functions/package.json.
Sample Database Structure
Users sign into the app and are requested to enable notifications on their browsers. If they successfully enable notifications the device token is saved into the datastore under /users/$uid/notificationTokens.:
/functions-project-12345
/users
/Uid-12345
displayName: "Bob Dole"
/notificationTokens
1234567890: true
photoURL: "https://lh3.googleusercontent.com/..."
If a user starts following another user we'll write to /followers/$followedUid/$followerUid:
/functions-project-12345
/followers
/followedUid-12345
followerUid-67890: true
/users
/Uid-12345
displayName: "Bob Dole"
/notificationTokens
1234567890: true
photoURL: "https://lh3.googleusercontent.com/..."
Trigger rules
The function triggers every time the value of a follow flag changes at /followers/$followedUid/$followerUid.
Index.js
/**
* Copyright 2016 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
/**
* Triggers when a user gets a new follower and sends a notification.
*
* Followers add a flag to `/followers/{followedUid}/{followerUid}`.
* Users save their device notification tokens to `/users/{followedUid}/notificationTokens/{notificationToken}`.
*/
exports.sendFollowerNotification = functions.database.ref('/followers/{followedUid}/{followerUid}')
.onWrite((change, context) => {
const followerUid = context.params.followerUid;
const followedUid = context.params.followedUid;
// If un-follow we exit the function.
if (!change.after.val()) {
return console.log('User ', followerUid, 'un-followed user', followedUid);
}
console.log('We have a new follower UID:', followerUid, 'for user:', followerUid);
// Get the list of device notification tokens.
const getDeviceTokensPromise = admin.database()
.ref(`/users/${followedUid}/notificationTokens`).once('value');
// Get the follower profile.
const getFollowerProfilePromise = admin.auth().getUser(followerUid);
// The snapshot to the user's tokens.
let tokensSnapshot;
// The array containing all the user's tokens.
let tokens;
return Promise.all([getDeviceTokensPromise, getFollowerProfilePromise]).then(results => {
tokensSnapshot = results[0];
const follower = results[1];
// Check if there are any device tokens.
if (!tokensSnapshot.hasChildren()) {
return console.log('There are no notification tokens to send to.');
}
console.log('There are', tokensSnapshot.numChildren(), 'tokens to send notifications to.');
console.log('Fetched follower profile', follower);
// Notification details.
const payload = {
notification: {
title: 'You have a new follower!',
body: `${follower.displayName} is now following you.`,
icon: follower.photoURL
}
};
// Listing all tokens as an array.
tokens = Object.keys(tokensSnapshot.val());
// Send notifications to all tokens.
return admin.messaging().sendToDevice(tokens, payload);
}).then((response) => {
// For each message check if there was an error.
const tokensToRemove = [];
response.results.forEach((result, index) => {
const error = result.error;
if (error) {
console.error('Failure sending notification to', tokens[index], error);
// Cleanup the tokens who are not registered anymore.
if (error.code === 'messaging/invalid-registration-token' ||
error.code === 'messaging/registration-token-not-registered') {
tokensToRemove.push(tokensSnapshot.ref.child(tokens[index]).remove());
}
}
});
return Promise.all(tokensToRemove);
});
});
package.json
{
"name": "fcm-notifications-functions",
"description": "Send FCM notifications Firebase Functions sample",
"dependencies": {
"firebase-admin": "~5.11.0",
"firebase-functions": "^1.0.0"
},
"devDependencies": {
"eslint": "^4.13.1",
"eslint-plugin-promise": "^3.6.0"
},
"scripts": {
"lint": "./node_modules/.bin/eslint --max-warnings=0 .",
"serve": "firebase serve --only functions",
"shell": "firebase experimental:functions:shell",
"start": "npm run shell",
"deploy": "firebase deploy --only functions",
"logs": "firebase functions:log"
},
"private": true
}
来源：https://stackoverflow.com/questions/50580988/sending-push-notification-using-cloud-function-when-a-new-node-is-added-in-fireb