Node.js 用于发送通知的云函数不工作

我正在尝试在添加新游戏时向“玩家2”发送通知。 这是我的密码：

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);


exports.sendNewGameNotification= functions.database.ref('/GAMES/{gameId}/PLAYER 2').onWrite(event => {
const player2uid = event.params.val;

const getDeviceTokensPromise = admin.database().ref(`/USERS/${player2uid}/fcm`).once('value');

return Promise.all([getDeviceTokensPromise]).then(results => {

const tokensSnapshot = results[0];
// Notification details.
const payload = {
  'data': { 
        'title': "Tienes una nueva partida"
  }
};

// Listing all tokens, error here below.
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);
});
});
});

执行时，firebase控制台中显示

 TypeError: Cannot convert undefined or null to object

---

例如，如果它为空，但fcm存在，我做错了什么？

我想不是这样：

const player2uid = event.params.val;

你想要这个：

const player2uid = event.data.val();

编辑：

此代码更新包含一些附加检查和简化。这对我有用

用于存储令牌的数据库结构至关重要。标记是键，而不是值。这些值不重要，可以是简单的占位符，例如布尔值

例如：

  "USERS" : {
    "Roberto" : {
      "fcm" : {
        "eBUDkvnsvtA:APA...rKe4T8n" : true
      }
    },
    "Juan" : {
      "fcm" : {
        "fTY4wvnsvtA:APA91bGZMtLY6R...09yTLHdP-OqaxMA" : true
      }
    }
  }

---

谢天谢地，问题解决了，但现在它给我带来了一个错误：提供的注册令牌无效。确保它与客户端应用程序从FCM注册收到的注册令牌匹配知道为什么吗？你是在

/USERS/${player2uid}/FCM

下存储一个令牌还是多个令牌？我只存储一个令牌。你是如何修复它的？哦，伙计，感谢你指出令牌必须作为密钥放入数据库中！你救了我几个小时的头撞在墙上。

exports.sendNewGameNotification= functions.database.ref('/GAMES/{gameId}/PLAYER 2').onWrite(event => {
const player2uid = event.data.val();

return admin.database().ref(`/USERS/${player2uid}`).once('value').then(snapshot => {
   if (!snapshot.exists()) {
        console.log('Player not found:', player2uid);
        return;
    }
    const tokensSnapshot = snapshot.child('fcm');
    if (!tokensSnapshot.exists()) {
        console.log('No tokens for player: ', player2uid);
        return;
    }

    // Notification details.
    const payload = {
      'data': {
            'title': "Tienes una nueva partida"
      }
    };

    // Listing all tokens, error here below.
    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);
});
});
});