Firebase Unique Value

Question

Having the following structure in Firebase:

-events
     -Firebase Push ID for Event 1
         **-key: \"DF2342\"**
         -name: \"Event 1\"
         -cr         


        

Answer 1

Since your application requires that you can't use childByAutoId, a way to make sure you're generating unique IDs would be to store an additional table in firebase of just the IDs you've generated. For example:

"keys": {
  "DF2342": true,
  "AB1232": true,
  ...
}

Then when you generate your key you can do something like this:

let boardKey = self.keyGenHelper.generateUniqueKey()
var validData = false
while(!validData){
// check /keys in the database to see if we've already generated a key of this value
databaseRef?.child("keys").queryEqual(toValue: boardKey).observeSingleEvent(of: .childAdded, with: { (snapshot) in
    if !snapshot.exists() {
        let boardIdRef = self.databaseRef!.child("events").childByAutoId()
        boardIdRef.setValue(board.generateDictionary(key: boardKey))
        completion(boardKey, boardIdRef.key)
        validData = true
    }
}, withCancel: {(error) in
    print(error)
})

You also need to make sure you're writing the newly generated key to /keys.