如何在Firebase的云功能中获取内部子对象? [英] How to get inner child in cloud function for Firebase?

问题描述

这是我的数据库，我想在 PUBLISHED_CONTENT_LIKES 的子级上触发onWrite事件.当我在 publishedContentId1 下添加另一个userId时，可以使用 event.params.pushId 在我的云函数中将contentId标识为 publishedContentId1 .

Here is my database and I want to trigger onWrite event on children of PUBLISHED_CONTENT_LIKES. When I add another userId under publishedContentId1, I can identify contentId as publishedContentId1 in my cloud function using event.params.pushId.

exports.handleLikeEvent = functions.database.ref('/USER_MANAGEMENT/PUBLISHED_CONTENT_LIKES/{pushId}')
.onWrite(event => {

  // Grab the current value of what was written to the Realtime Database.
  //const userId = event.data.child(publishedContentId);
  //const test = event.params.val();
  const publishedContentId = event.params.pushId;

  var result = {"publishedContentId" : "saw"}
  // 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.parent.child('PUBLISHED_CONTENTS/'+publishedContentId).set(result);
});

但是我也想获取新添加的 userId .如何使用上述事件获取该userId?

However I want to get newly added userId as well. How to get that userId using above event?

推荐答案

您可以获取正在 event.data 下写入的数据.要确定新的用户ID，请执行以下操作:

You can get the data that is being written under event.data. To determine the new user ID:

event.data.val().userID

我建议观看最新的编写数据库函数时的火爆，因为它恰好涵盖了此内容主题.

I recommend watching the latest Firecast on writing Database functions as it covers precisely this topic.

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