firebasecloud函数在回调中获取文档

Question

使用firebase云函数，如果我想在回调中引用文档('/users/'+userId(，我会这样做吗？userId在第一个快照中，所以我需要调用另一个异步调用来获取用户文档，但我认为我的语法有问题，因为这会导致错误。

exports.onCommentCreation = functions.firestore.document('/forum/threads/threads/{threadId}/comments/{commentId}')
 .onCreate(async(snapshot, context) => {
     var commentDataSnap = snapshot; 
     var userId = commentDataSnap.data().userId; 
     var userRef = await functions.firestore.document('/users/' + userId).get();
     var userEmail = userRef.data().email; 
});

Answer 1

在行var userRef = await functions.firestore.document('/users/' + userId).get();上将functions.firestore.document更改为admin.firestore().doc。

类似这样的东西：

const functions = require("firebase-functions");
const admin = require("firebase-admin");
const db = admin.firestore();
exports.onCommentCreation = functions.firestore
  .document('/forum/threads/threads/{threadId}/comments/{commentId}')
  .onCreate(async (snapshot, context) => {
    // use const because the values are not changing
    const userId = snapshot.data().userId;
    const userRef = await db.doc('/users/' + userId).get(); // <-- this line
    const userEmail = userRef.data().email;
  });