如何从云端函数内部执行查询？ [英] How to run query from inside of Cloud function?

问题描述

假设我在数据库上有一个特定的触发器请考虑 Firebase入门指南中提供的示例。

  //监听添加到/ messages /：pushId / original的新消息，并创建一个
 //大写的/ message /：pushId / uppercase 
 exports.makeUppercase = functions.database.ref（'/ messages / {pushId} / original'）
 .onWrite（event => {
 //获取写入实时数据库的当前值
 const original = event.data.val（）; 
 console.log（'Uppercasing'，event.params.pushId，original ）; 
 const uppercase = original.toUpperCase（）; 
 //我喜欢在这里进行一个查询，只是简单的检索基于提供的ID 
 //在
之类的函数内部执行异步任务时，必须返回一个Promise，写入Firebase实时数据库。 
 //在实时数据库中设置大写兄弟会返回一个Promise。 
 return event.data.ref.parent.child（'uppercase'）。set（uppercase）; 
}）; 
  

我应该导入哪些 模块？
如何在数据库上执行查询？

预先感谢您的回答！

您可以使用 Node.js Admin SDK

a> for this：
$ b $ pre $ const $ functions（'firebase-functions'）;
const admin = require（'firebase-admin'）;
admin.initializeApp（functions.config（）。firebase）;

exports.makeUppercase = functions.database $ b $ .ref（'/ messages / {pushId} / original'）
.onWrite（event => {
return admin.database（）。ref（'/ other'）
.orderByChild（'id'）。equalTo（event.params.pushId）
.once（'value'）。then（snapshot => ; {
// there，I queried！
}）;
}）;

I'd like to perform a query on my database once a cloud function on my Firebase app is called.

Let's say I have a certain trigger on the database, consider the example provided in the get started guide on Firebase.

// Listens for new messages added to /messages/:pushId/original and creates an
// uppercase version of the message to /messages/:pushId/uppercase
exports.makeUppercase = functions.database.ref('/messages/{pushId}/original')
  .onWrite(event => {
      // Grab the current value of what was written to the Realtime Database.
      const original = event.data.val();
      console.log('Uppercasing', event.params.pushId, original);
      const uppercase = original.toUpperCase();
      // I'D LIKE TO PERFORM A QUERY HERE, JUST A SIMPLE RETRIEVE BASED ON THE ID PROVIDED
     // You must return a Promise when performing asynchronous tasks inside a Functions such as
     // writing to the Firebase Realtime Database.
     // Setting an "uppercase" sibling in the Realtime Database returns a Promise.
     return event.data.ref.parent.child('uppercase').set(uppercase);
});

Which modules should I import, if any? How can I perform the query on the DB?

Thank you in advance for your answer!

解决方案

You can use the Node.js Admin SDK for this:

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

exports.makeUppercase = functions.database
  .ref('/messages/{pushId}/original')
  .onWrite(event => {
    return admin.database().ref('/other')
      .orderByChild('id').equalTo(event.params.pushId)
      .once('value').then(snapshot => {
        // there, I queried!
      });
  });

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