可选密钥在firebase数据库中生成

Question

此代码负责在登录用户的自动生成密钥下上传文本和帖子的时间，该密钥位于第一行的函数didtappost中

@IBOutlet weak var post: UIButton!
@IBOutlet weak var newpost: UITextView!


var databaseref = FIRDatabase.database().reference()
var loggedinuser : AnyObject?
override func viewDidLoad()
{


    super.viewDidLoad()
    self.loggedinuser = FIRAuth.auth()?.currentUser
    newpost.textContainerInset = UIEdgeInsetsMake(30, 20, 20, 20)
    newpost.text = "what is new?"
    newpost.textColor = UIColor.lightGray
}
@IBAction func didtapcancel(_ sender: Any) {

    dismiss(animated: true, completion: nil)   
}

func textFieldShouldReturn(_ textfield: UITextField) -> Bool {
    textfield.resignFirstResponder()
    return false
}

@IBAction func didtappost(_ sender: Any) {
    if(newpost.text.characters.count>0)
    {
        let key = databaseref.child("posts").childByAutoId().key

        let childupdates = ["/posts/\(self.loggedinuser!.uid)/\(key)/text ": newpost.text,"/posts/\(self.loggedinuser!.uid)/\(key)/time":"\(Date().timeIntervalSince1970)"
            ] as [String : Any]

        self.databaseref.updateChildValues(childupdates)
        dismiss(animated: true, completion: nil)

    }
}
}