调用快照的 Firebase 云函数“ForEach”子项

Question

我正在尝试部署一个 Firebase 云函数，该函数向其关联的收件人发送 x 条文本消息的文本消息。当对“发送”实时数据库引用进行更新时，在我的 iOS 应用程序中触发该函数，表明用户已按下“发送”按钮。

我的 Firebase 结构是

  {
  "user1uid": {
    "send": false
    "messagesToSend": {
      "messageuid1": {
         "messageText": "What's for dinner?",
         "recipientNumber": "+18017378888",
      }
      "messageuid2:
         "messageText": "Who won the Cowboys game?",
         "recipientNumber": "+18017377787",
      }
   }
   "user2uid": {
    "send": false
    "messagesToSend": {
      "messageuid1": {
         "messageText": "What's for dinner?",
         "recipientNumber": "+18017378888",
      }
      "messageuid2:
         "messageText": "Who won the Cowboys game?",
         "recipientNumber": "+18017377787",
      }
   }
}

我的代码目前只发送一条消息，我不确定如何为每个用户正确遍历messagesToSend节点并发送其中的所有消息。

我一直在尝试遵循位于此处的教程。我查看了以下 Stack Overflow 响应，但无法解读或从中得出解决方案：

Firebase 云功能承诺
我是否正确使用 ForEach？

我发送一条消息的 index.js 代码如下：

const functions = require('firebase-functions');

// The Firebase Admin SDK to access the Firebase Realtime Database.
const admin = require('firebase-admin');
admin.initializeApp();

const twilio = require('twilio')

const accountSid = functions.config().twilio.sid;
const authToken  = functions.config().twilio.token;

const client = new twilio(accountSid, authToken);

const twilioNumber = functions.config().twilio.number;


// Start cloud function
exports.sendSecrets = functions.database
       .ref('/{uid}/send')
       .onUpdate((change,context) => {

    const uid = context.params.uid;

    return admin.database().ref(uid+'/messagesToSend').once('value').then(snapshot => {

      snapshot.forEach(function(childSnapshot) {

          var key = childSnapshot.key;
          var messageData = childSnapshot.val();
          **if (messageData.sanitized) return true;**
          var message = messageData.messageText;
          var phoneNumber = messageData.recipientNumber;

          const textMessage = {
            body: `From My App - ${message}`,
            from: twilioNumber, // From Twilio number
            to: phoneNumber  // Text to this number
          }
          return client.messages.create(textMessage)
        })
        **return snapshot.ref.toString();**
    });
}); 

请注意，两端标有 ** 的行表明我知道我需要根据收到的错误消息返回一些内容，表明“每个 then() 应该返回一个值或抛出”。

Answer 1

我假设您正在使用twilio-node使用 promise的库：https : //www.npmjs.com/package/twilio。

由于要并行发送多条消息，因此必须使用Promise.all()，如下所示：

const functions = require('firebase-functions');

// The Firebase Admin SDK to access the Firebase Realtime Database.
const admin = require('firebase-admin');
admin.initializeApp();

const twilio = require('twilio')

const accountSid = functions.config().twilio.sid;
const authToken  = functions.config().twilio.token;

const client = new twilio(accountSid, authToken);

const twilioNumber = functions.config().twilio.number;


// Start cloud function
exports.sendSecrets = functions.database
       .ref('/{uid}/send')
       .onUpdate((change,context) => {

    const uid = context.params.uid;

    return admin.database().ref(uid+'/messagesToSend').once('value')
    .then(snapshot => {

      const promises = [];

      snapshot.forEach(function(childSnapshot) {

          var key = childSnapshot.key;
          var messageData = childSnapshot.val();
          //**if (messageData.sanitized) return true;**
          var message = messageData.messageText;
          var phoneNumber = messageData.recipientNumber;

          const textMessage = {
            body: `From My App - ${message}`,
            from: twilioNumber, // From Twilio number
            to: phoneNumber  // Text to this number
          }

          promises.push(client.messages.create(textMessage));
      })

      return Promise.all(promises);
    })
    // Edits made below to parentheses/brackets
    .then(results => {
      //Do whatever you want !!
      // e.g. print the results which will be an array of messages
      // (see https://www.twilio.com/docs/libraries/node#testing-your-installation)
    })            
}); 

您也可以简单地返回Promise.all()如下：

....
     return Promise.all(promises);
   })
});