javascript如何通过云函数触发firestore集合

Question

每当我点击应用程序中的以下按钮时，我想从现有的关注者集合和视频集合中触发一个新集合（时间线集合）

现在的问题是，云函数是从视图日志创建的，但不会创建新集合（时间线集合）

下面是云函数的代码，我将关注者集合和视频集合作为目标，创建一个新的时间线集合。我期待你的帮助

• Videos collection

• Followers collection

• Cloud function view logs

const functions = require("firebase-functions");
    const admin = require("firebase-admin");
    admin.initializeApp();
    
    // // Create and Deploy Your First Cloud Functions
    // // https://firebase.google.com/docs/functions/write-firebase-functions
    //
    // exports.helloWorld = functions.https.onRequest((request, response) => {
    //  response.send("Hello from Firebase!");
    // });
    exports.onCreateFollower = functions.firestore
      .document("/followers/{userId}/userFollowers/{userfollowerId}")
      .onCreate(async (snapshot, context) => {
        console.log("The Event has Created The Follower", snapshot.id);
        const userId = context.params.userId;
        const userfollowerId = context.params.userfollowerId;
    
        // 1) Create followed users posts ref
        const followedUserVideosCollection = admin
          .firestore()
          .collection("videos")
          .doc(userId)
          .collection("userVideos"); 
    
        // 2) Create following user's timeline ref
        const timelineVideosCollection = admin
          .firestore()
          .collection("timeline")
          .doc(userfollowerId)
          .collection("timelinePosts");
    
        // 3) Get followed users posts
        const querySnapshot = await followedUserVideosCollection.get();
    
        // 4) Add each user post to following user's timeline
        querySnapshot.forEach(doc => {
          if (doc.exists) {
            const videoId = doc.id;
            const videoData = doc.data();
            timelineVideosCollection.doc(videoId).set(videoData);
          }
        });
      });

Answer 1

我找出了错误“querySnapshot.forEach不是函数”的原因。根据to this answer，您需要首先查询集合，因为get()返回的是文档而不是快照。下面是一个示例代码（请参见步骤3）：

// 1) Create followed users posts ref
const followedUserVideosCollection = admin
    .firestore()
    .collection("videos")
    .doc("Videos 1") // I changed the value with your sample for test purposes and also because I'm not sure how you fill up this doc.
    .collection("userVideos");

// 2) Create following user's timeline ref
const timelineVideosCollection = admin
    .firestore()
    .collection("timeline")
    .doc(userfollowerId)
    .collection("timelinePosts");

// 3) Get followed users posts & Add each user post to following user's timeline
await followedUserVideosCollection.where('id', '==', 0).get().then((querySnapshot) => {
    if (querySnapshot) {
        querySnapshot.forEach(doc => {
            if (doc) {
                const videoId = doc.id;
                const videoData = doc.data();
                timelineVideosCollection.doc(videoId).set(videoData);
            }
        });
    }else {
        console.log("Document not found");
    }
}).catch((error) => {
    console.log(error);
});

解决方案是创建一个过滤器，并确保您要查找的文档与过滤器匹配。例如，子集合userVideos中的文档应该有一个名为id的字段，其值为0

您可能需要重新构建数据库以修复我在其中放置注释的行，但这段代码应该编写timeline集合