Firebase數據庫計數

Question

在聊天消息中添加計數以上傳到Google Firebase數據庫的最佳方法是什么？ 我用的方法是，計數不斷重新初始化，因此弄亂了數據。

問題：上載聊天消息以免彼此干擾的最佳方法是什么？ 通過firebase。

+ general_room 1,2,3,4

代表發送的每個messaga的數字。

import Foundation
import Firebase
import FirebaseDatabase
import FirebaseStorage

var count = 0

func UploadGeneralChatRoom(message : String) {

    //Firebase Initialization
    var ref: FIRDatabaseReference!
    //var storage: FIRStorageReference!
    let userID = FIRAuth.auth()?.currentUser?.uid
    ref = FIRDatabase.database().reference()
    //storage = FIRStorage.storage().reference()


    //Get Data from database resend to database
    ref.child("Users").child(userID!).observeSingleEvent(of: .value, with: {(snapshot) in

        let snapDict = snapshot.value as? NSDictionary
        let username = snapDict?["Username"] as? String ?? ""
        let firebaseUserPhotoURL = snapDict?["photo_url"] as? String ?? ""

        count = count + 1
        print("Count: ", count)


        let countString = String(count)

        print("CountStrig: " + countString)


        ref.child("general_room").child(countString).setValue(["Username": username, "uid": userID!, "Message" : message, "photo_url" : firebaseUserPhotoURL])


    })

}

Answer 1

最初的問題尚不清楚，但是如果您要將消息上傳到聊天室，則結構如下：

users
  uid_0
   name: "Kirk"
  uid_1
   name: "Spock"
  uid_2
   name: "McCoy"

chat_rooms
  room_0
   name: "Bridge Chat Room"
   messages:
     message_0:
       msg: "This is a message posted by Spock"
       uid: "uid_1"
     message_1:
       msg: "Message posted by Kirk"
       uid: "uid_0"

以及一些用於在chat_rooms，room_0中創建新消息的代碼（可能會被壓縮，但為了便於閱讀而顯得冗長）

let ref = rootRef.child("chat_rooms")
let roomRef = ref.child("room_0")
let messagesRef = roomRef.child("messages")
let msgRef = messagesRef.childByAutoId()
let data = ["msg": "a message posted by McCoy",
            "uid": "uid_2"]
msgRef.setValue(data)

將導致

chat_rooms
  room_0
   name: "Bridge Chat Room"
   messages:
     message_0:
       msg: "This is a message posted by Spock"
       uid: "uid_1"
     message_1:
       msg: "Message posted by Kirk"
       uid: "uid_0"
     message_2:
       msg: "a message posted by McCoy"
       uid: "uid_2"

message_0，message_1等是使用childByAutoId創建的鍵。

如果您想知道有多少條消息，這是一種選擇

messagesRef.observeSingleEvent(of: .value, with: { snapshot in
    print(snapshot.childrenCount)
})

和結果

3