如何在iOS swift中使用firestore获取用户的帖子数 [英] How to get post count of user using firestore in iOS swift

问题描述

我已将用户帖子、关注者和关注者从 firebase 迁移到 firestore.现在我已经迁移了帖子、关注者以及关注和发布，关注者也算.

I have migrated user post, followers and following from from firebase to firestore. Now i have migrated post, followers and following and post, followers count too.

这里是我从 firebase 迁移到 firestore 的代码.

Here the code i have migrated from firebase to firestore.

 import Foundation
import FirebaseDatabase
 import FirebaseFirestore

class FollowApi {


var REF_FOLLOWERS = Database.database().reference().child("followers")
var REF_FOLLOWING = Database.database().reference().child("following")
let db = Firestore.firestore()

func followAction(withUser id: String) {


    let docRef = db.collection("user-posts").document(id)

    docRef.getDocument { (document, error) in
        if let document = document, document.exists {
            let dataDescription = document.data().map(String.init(describing:)) ?? "nil"
            print("Document data: \(dataDescription)")

            self.db.collection("feed").document(API.User.CURRENT_USER!.uid).setData([document.documentID: true])

        } else {
            print("Document does not exist")
        }
    }



   self.db.collection("followers").document(id).setData([API.User.CURRENT_USER!.uid: true])
   self.db.collection("following").document(API.User.CURRENT_USER!.uid).updateData([id: true])

}

func unFollowAction(withUser id: String) {

    let docRef = db.collection("user-posts").document(id)

    docRef.getDocument { (document, error) in
        if let document = document, document.exists {
            let dataDescription = document.data().map(String.init(describing:)) ?? "nil"
            print("Document data: \(dataDescription)")



 self.db.collection("feed").document(API.User.CURRENT_USER!.uid).delete()


        } else {
            print("Document does not exist")
        }
    }



    self.db.collection("followers").document(id).setData([API.User.CURRENT_USER!.uid: NSNull()])
    self.db.collection("following").document(API.User.CURRENT_USER!.uid).setData([id: NSNull()])

 }

func isFollowing(userId: String, completed: @escaping (Bool) -> Void) {

    let docRef = db.collection("followers").document(userId)

    docRef.getDocument { (document, error) in
        if let document = document, document.exists {

            print("documnetData::::\(String(describing: document.data()))")
            if let dataDescription = document.data(), let _ = dataDescription[API.User.CURRENT_USER!.uid] as? Bool {

                completed(true)
            }

            completed(false)

        } else {
           completed(false)
        }
    }


}





    func fetchCountFollowing(userId: String, completion: @escaping (Int) -> Void) {
  //     REF_FOLLOWING.child(userId).observe(.value, with: {
  //                snapshot in
 //                let count = Int(snapshot.childrenCount)
 //                completion(count)
 //            })



        db.collection("following").document(userId).getDocument { (querySnapshot, error) in

            let count = Int((querySnapshot?.documentID)!)
            print("followingCount::::\(String(describing: count))")
            completion(count!)
        }

    }

 }//followAPI

我试图从 firestore 获取以下计数.

I tried to get following counts from firestore.

  let count = Int((querySnapshot?.documentID)!)
            print("followingCount::::\(String(describing: count))")
            completion(count!)

但还没有显示任何内容.我不知道我犯了什么错误?

but does not show any any yet all. I do not know what mistake i have done ?

非常感谢任何帮助....

Any help much appreciated pls....

推荐答案

如果您正在查询 collection 那么它的 snapshot 将包含一个 数组文档.您想要获得的是一个 documentID，它与 Firebase 中的 key 相同.

If you're querying for a collection then its snapshot will contain an array of documents. What are you trying to get is a documentID which is same as key in Firebase.

Firestore |Firebase

documentID = 快照.key

documentID = snapshot.key

documentData = 快照.值

documentData = snapshot.value

现在，来到重点，这里是你需要得到的计数.

Now, Come to the main point and here is what you need to get the count.

let count = querySnapshot?.documents.count
print(count)

编辑评论: 我如何迁移 REF_FOLLOWING.child(userId).observe(.value, with: { snapshot in let count = Int(snapshot.childrenCount) completion(count)) }) 到firestore

基于附加的数据库结构，您正在获取与 userId 相对应的 following，这是一个 Document.

Based on attached DB structure you're fetching following corresponding to userId which is a Document.

REF_FOLLOWING.document(userId).getDocument { (snapshot, error) in
    if let _error = error {
       print(_error.localizedDescription)
       return
    }

    guard let _snapshot = snapshot else {return}

    /// This is a single document and it will give you "[String:Any]" dictionary object. So simply getting its count is the result you needed.
    let dict = _snapshot.data()
    print(dict.count)
}

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