firebase云功能函数循环执行 [英] firebase cloud function function looping in execution

问题描述

我想制作一份现有数据的简历，但Firebase云端功能会做循环，以至于我所做的总结是无效的。有没有解决我的问题？
谢谢

这个在我的屏幕上拍摄

数据库建设
，

log

  const functions = require （火力函数）; 
 const admin = require（firebase-admin）; 
 admin.initializeApp（functions.config（）。firebase）; 
 var db = admin.database（）; 
 exports.makePurchaseSummaryAdd = functions.database.ref（'/ invoice_data / {pushIdInvoice} / item / {pushIdItem}'）
 .onCreate（event => {
 var name = event。 （）; 
 var quantity = '/ invoice_data /'+ event.params.pushIdInvoice +'/ idUser'）; 
 ref.on（value，function（snapshot）{
 var refUser = db.ref（'/ user_data / （snapshotUser.ex（））; //这个函数的作用在于： {
 console.log（'Ada Data'）; 
 var count = snapshotUser.val（）; 
 var newCount = quantity + count; $ b $ refUser.set（newCount）; 
 console.log（'create'，count，newCount，name.toUpperCase（））; 
} 
 else {
 console.log（'Tidak Ada Data'）; 
 
}，function（errorObject）{
 console.log（The read failed：+ errorObject.code）; 
}）; 
}，function（errorObject）{
 console.log（The read failed：+ errorObject.code）; 
}）; 
返回true; 
}）; 
  

解决方案

=https://firebase.google.com/docs/reference/admin/node/admin.database.Reference#on =nofollow noreferrer> on（）方法。这使得监听器被连接：

你的回调将被初始数据触发，而
只要数据改变就会触发

您应该改用：

$ b

侦听指定的一个事件事件类型，然后
停止监听

您的代码正在循环，因为您附加了一个侦听器 refUser .on（...），然后改变回调中该位置的值： refUser.set（newCount）;

I want to make a resume of the existing data but Firebase cloud function does the looping so that the summation I made is not valid. is there a solution to my problem? thank you

this in my screen shoot

database construction ,

log

const functions = require('firebase-functions');
const admin = require("firebase-admin");
admin.initializeApp(functions.config().firebase);
var db = admin.database();
exports.makePurchaseSummaryAdd = functions.database.ref('/invoice_data/{pushIdInvoice}/item/{pushIdItem}')
    .onCreate(event => {
        var name = event.data.child('itemName').val();
        var quantity = event.data.child('quantity').val();

        var ref = db.ref('/invoice_data/' + event.params.pushIdInvoice + '/idUser');
        ref.on("value", function(snapshot) {
            var refUser = db.ref('/user_data/' + snapshot.val() + '/purchaseSummary/' + name.toUpperCase());
            refUser.on("value", function(snapshotUser) {
                if (snapshotUser.exists()){
                    console.log('Ada Data');
                    var count = snapshotUser.val();
                    var newCount = quantity + count;
                    refUser.set(newCount);
                    console.log('create', count, newCount, name.toUpperCase());
                }
                else {
                    console.log('Tidak Ada Data');
                }
            }, function (errorObject) {
              console.log("The read failed: " + errorObject.code);
            });
        }, function (errorObject) {
          console.log("The read failed: " + errorObject.code);
        });
        return true;
    });

解决方案

You are attaching database reference listeners using the on() method. This leaves the listener attached:

Your callback will be triggered for the initial data and again whenever the data changes

You should instead use once():

Listens for exactly one event of the specified event type, and then stops listening

Your code is looping because you attach a listener refUser.on(...) and then are changing the value at that location in the callback: refUser.set(newCount);

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