Automatically delete data from Firebase Database - swift

Question

I have seen some other questions asked but I am having trouble getting it to work. I have a Mac app coded in swift and it has a Firebase login but the user types a key in that is stored on Firebase, is there a way to automatically delete that key when the user has successfully used it?
This is my database.
This is the code that is used currently.
import Cocoa
import FirebaseAuth
import FirebaseDatabase
class LoginViewController: NSViewController {
#IBOutlet weak var textUsername: NSTextField!
#IBOutlet weak var textPassword: NSSecureTextFieldCell!
#IBOutlet weak var btnLogin: NSButton!
var keyArray = \[Int64\]()
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear() {
}
func getLoginState() -> Bool{
let state = UserDefaults.standard.bool(forKey: "isRegistered")
if (state) {
return true
} else {
return false
}
}
override func viewDidAppear() {
let state = self.getLoginState()
if (state){
self.performSegue(withIdentifier: NSStoryboardSegue.Identifier(rawValue: "loginsegue"), sender: nil)
self.view.window?.close()
}
var ref: DatabaseReference!
ref = Database.database().reference()
let keyRef = ref.child("key1")
keyRef.observe(DataEventType.childAdded, with: { (snapshot) in
// let postDict = snapshot.value as? \[String : AnyObject\] ?? \[:\]
let keyStr = snapshot.value as? Int64
if let actualPost = keyStr{
self.keyArray.append(actualPost)
}
})
}
#IBAction override func dismissViewController(_ viewController: NSViewController) {
dismiss(self)
}
#IBAction func close(sender: AnyObject) {
self.view.window?.close()
}
#IBAction func onSignup(_ sender: Any) {
// self.performSegue(withIdentifier: NSStoryboardSegue.Identifier(rawValue: "gotosignup"), sender: sender)
// self.view.window?.close()
}
func dialogOK(question: String, text: String) -> Void {
let alert: NSAlert = NSAlert()
alert.messageText = question
alert.informativeText = text
alert.alertStyle = NSAlert.Style.warning
alert.addButton(withTitle: "OK")
alert.runModal()
}
#IBAction func onLogin(_ sender: Any) {
//self.btnLogin.isEnabled = false
var isKey = false
if (!self.textUsername.stringValue.isEmpty) {
for key in keyArray{
if(Int64(self.textUsername.stringValue)! == key)
{
UserDefaults.standard.set(true, forKey:"isRegistered")
self.performSegue(withIdentifier: NSStoryboardSegue.Identifier(rawValue: "loginsegue"), sender: nil)
self.view.window?.close()
isKey = true
}
}
if (!isKey){
self.dialogOK(question: "Error", text: "Invalid Key")
}
} else {
self.dialogOK(question: "Error", text: "Please Input Key")
}
}
}

Answer 1

You can't sort your database like that and expect a working code, even if there's any. It will make a messy code:
You need to:
Sort your database like [1220:0]. the key first. 0 & 1 as an indicator if it's used or not.
Once the user taps onLogin() you need to set the used key value to 1
Setup Cloud Functions to check if the used key is equal to 1, if yes. then remove the key.
Do the rest of the work.
Related Articles to get you started:
Extend Realtime Database with Cloud Functions
functions.database.RefBuilder