Firebase数据库获取了更改值的父母和祖父母的密钥？

Question

我正在尝试为我的移动应用设置推送通知，我有以下FireBase数据库，我想要做的是当isOpen值发生变化时，我需要得到它的父母和大父母＆＃ 39;发送适当通知的密钥。可以在红色框中看到。我可以得到父母的钥匙，但我无法得到父母的钥匙。我目前的代码就是我从https://github.com/firebase/functions-samples/tree/master/fcm-notifications

获取的代码

任何帮助？

/**
 * 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(functions.config().firebase);

/**
 * 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.sendUserNotification = functions.database.ref('/devices').onUpdate( event => {
  console.log("event.data: ", event.data);
  console.log("event.data.toJSON(): ", event.data.toJSON());



  const userUid = event.auth.variable.user_id;
  const deviceUid = event.params.deviceUid;

  event.data.adminRef.on('child_changed', function(snapshot){
    console.log("snapshot: ", snapshot);
    console.log("snapshot.val(): ", snapshot.val());
    console.log("snapshot.key:", snapshot.key);
    //snapshot.key: 1f2d34d
    console.log("snapshot.ref.parent.key:", snapshot.ref.parent.key);
    //snapshot.ref.parent.key: devices

    const deviceId = snapshot.key;



    //const userUid = event.params.userUid;
    // If un-follow we exit the function.
    // console.log("itemSnapshot: ", itemSnapshot);
    if (!event.data.val()) {
      return console.log('User ', userUid, 'has device ', deviceUid);
    }
    console.log('We have a new user UID:', userUid, 'for device:', deviceUid);

    // Get the list of device notification tokens.
    const getDeviceTokensPromise = admin.database().ref(`/users/${userUid}/pushToken`).once('value');

    // Get the follower profile.
    const getUserProfilePromise = admin.auth().getUser(userUid);

    const getDeviceInformation = admin.database().ref('/devices/${deviceUid}/')

    return Promise.all([getDeviceTokensPromise, getUserProfilePromise]).then(results => {
      const tokensSnapshot = results[0];
      const user = 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: 'Device Informatiın',
          body: `${follower.displayName} is now following you.`,
          icon: follower.photoURL
        }
      };

      // Listing all tokens.
      const 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);
      });
    });




  });





});

Answer 1

答案很延迟。获取父母的钥匙：

snap.ref.parent.key;