如何将Firebase实时数据库自动写入Firestore？

Question

我目前正在做一个项目，该项目使用Arduino收集数据并将数据存储在云端，并将数据显示在移动应用程序的云端。从我尝试过的情况来看，Arduino只能将数据上传到Firebase实时数据库，但我的Flutter移动应用程序需要将数据存储在FiRest中。当实时数据库发生变化时，有没有办法将firebase实时数据库数据自动写入Fiback？

这是实时数据库结构：实时数据库结构

我想将数据附加到Firestore中的相应字段中，如下所示：firestore结构

我尝试过每5秒读取一次数据并将其写入Firebase，但似乎不是很有效：

final userDbRef = FirebaseDatabase.instance.ref("user/");
 String uid = globals.uid;

 Stream<DatabaseEvent> stream = userDbRef.onValue;

 // Subscribe to the stream!
 var subscription = stream.listen((DatabaseEvent event) {
   // print('Listening');
   dynamic values = event.snapshot.value;
   final data = new Map<String, dynamic>.from(values);

   globals.temp = data['temp'];
   globals.hr = data ['hr'];
   globals.spo2 = data['spo2'];
   globals.position = data['position'];
   globals.time = DateTime.parse(data['time']);
 });

 subscription.pause();

 String date = DateTime.now().add(const Duration(hours: 8)).toString().substring(0, 10);

 dynamic result = await DatabaseService(uid: uid).getUserData('patient');
 if (result[date].toString() == 'null') {
   await DatabaseService(uid: uid).updateSingleUserData('patient', {
     date: {
       'time': ['${date} 00:00:00.000'],
       'hr': [95],
       'temp': [36.5],
       'spo2': [98],
       'position': ['lying'],
     },
   });
 } else {
   List timeList = result[date]['time'];
   List hrList = result[date]['hr'];
   List tempList = result[date]['temp'];
   List spo2List = result[date]['spo2'];
   List positionList = result[date]['position'];

   if ((!timeList.contains(globals.time.toString())) & (globals.time.toString() != 'null')) {
     timeList.add(globals.time.toString());
     hrList.add(globals.hr);
     tempList.add(globals.temp);
     spo2List.add(globals.spo2);
     positionList.add(globals.position);

    await DatabaseService(uid:uid).updateSingleUserData('patient', {
       date: {
         'time': timeList,
         'hr': hrList,
         'temp': tempList,
         'spo2': spo2List,
         'position': positionList,
       },
     });
   }
 }
 subscription.resume();

谢谢。

Answer 1

有没有办法在实时数据库发生变化时，将firebase实时数据库数据自动写入Firestore？

是的，一种常见的方法是使用云函数，该函数在每次将新节点添加到实时数据库时自动触发。云功能在后端执行，即在Firebase/ Google Cloud基础架构上执行，因此您无需在Flutter应用程序中为此数据镜像/传输编写任何代码。

下面是一个包含通用路径的简单示例：

// The Cloud Functions for Firebase SDK to create Cloud Functions and set up triggers.
const functions = require('firebase-functions');

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


exports.duplicateToFirestore = functions.database.ref('/myRTDBPath/{pushId}')
    .onCreate((snapshot, context) => {
      // Grab the current value of what was written to the Realtime Database.
      const nodeVal = snapshot.val();

      // Write it to a Firestore collection

      return admin.firestore().collection('myFirestoreCollection').add(nodeVal);

    });

我允许您将RTDB节点值转换为您正在寻找的Firestore文档结构。