Firebase request for unique swift username
I searched for this question but none of them had an answer that worked for me.
I want to do this, when a user registers an account, it checks if the username they have already entered exists before creating the account. I tried using queries in firebase, but I just can't seem to get it to work.
Here is a picture of what my database data looks like: My firebase data tree
How can I use a query to find the string for the key "username"?
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You can go like this, do one function with a completion block to check the username already exists in your Firebase DB and create a new user based on that
func checkUserNameAlreadyExist(newUserName: String, completion: @escaping(Bool) -> Void) {
let ref = FIRDatabase.database().reference()
ref.child("users").queryOrdered(byChild: "username").queryEqual(toValue: newUserName)
.observeSingleEvent(of: .value, with: {(snapshot: FIRDataSnapshot) in
if snapshot.exists() {
completion(true)
}
else {
completion(false)
}
})
}
Now, just call this function when creating a new user:
self.checkUserNameAlreadyExist(newUserName: "Johnson") { isExist in
if isExist {
print("Username exist")
}
else {
print("create new user")
}
}
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This is how I do it:
var text = "Your username"
let dbRef = FIRDatabase.database().reference().child("users")
dbRef.queryOrdered(byChild: "name").queryEqual(toValue: text).observeSingleEvent(of: .value, with: { snapshot in
if !snapshot.exists() {
// Name doesn't exist
}
if let data = snapshot.value as? [String: [String: String]] {
// it should exist if it reaches here
}
})
Make sure your database rules index "users" node to "name" to optimize performance.
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I do it like this:
Register function:
@IBAction func signUpButtonTapped(_ sender: Any) {
User.getItemByLogin(for: userLogin.text!,
completion: { userItem in
if userItem == nil {
self.createAndLogin()
} else {
self.showAlertThatLoginAlreadyExists()
}
})
}
private func createAndLogin() {
FIRAuth.auth()!.createUser(withEmail: userEmail.text!,
password: userPassword.text!) { user, error in
if error == nil {
// log in
FIRAuth.auth()!.signIn(withEmail: self.userEmail.text!,
password: self.userPassword.text!,
completion: { result in
// create new user in database, not in FIRAuth
User.create(with: self.userLogin.text!)
self.performSegue(withIdentifier: "fromRegistrationToTabBar", sender: self)
})
} else {
print("\(String(describing: error?.localizedDescription))")
}
}
private func showAlertThatLoginAlreadyExists() {
let alert = UIAlertController(title: "Registration failed!",
message: "Login already exists.",
preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Ok", style: .default, handler: nil))
present(alert, animated: true, completion: nil)
}
User User function. This is the API as a class:
static func getItemByLogin(for userLogin: String,
completion: @escaping (_ userItem: UserItem?) -> Void) {
refToUsersNode.observeSingleEvent(of: .value, with: { snapshot in
for user in snapshot.children {
let snapshotValue = (user as! FIRDataSnapshot).value as! [String: AnyObject]
let login = snapshotValue["login"] as! String // getting login of user
if login == userLogin {
let userItem = UserItem(snapshot: user as! FIRDataSnapshot)
completion(userItem)
return
}
}
completion(nil) // haven't founded user
})
}
Along the way, you must change login
to username
.
Hope it helps
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