Firebase数据库计数

Question

What is the best way to add a count to your chat messages to upload to googles firebase database? The way I have it the count keeps geting re-initialized so it messes up the data.

QUESTION: What is the best way to upload chat messages so that they do not interfere with each other? via firebase.

+general_room 1,2,3,4

numbers representing each messaga sent.

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

The original question is pretty unclear but if you want to upload a message to a chat room, here's a structure:

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"

and some code to create a new message in chat_rooms, room_0 (this could be greatly condensed but leaving verbose for readability)

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)

will result in

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 etc are keys created with childByAutoId.

If you want to know how many messages there are, here's one option

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

and the result

3