检查用户名是否已经存在:Swift、Firebase [英] Check if username already exist's : Swift, Firebase

问题描述

我正在尝试检查用户名是否存在.当我调用 queryOrderedBychild 时，快照值始终可用，但它会打印我的整个数据库，而不仅仅是我请求 queryOrderby 的数据.当我调用 queryEqualToValue 时，它总是返回 null.我尝试了很多方法来解决这个问题.

I'm trying to check if a username exists or not. When I call queryOrderedBychild, snapshot value is always available but it will print down the whole database of mine, not just the data which I request queryOrderby. When I call queryEqualToValue, it always return null. I've tried many ways to figure it out.

这是我的代码:

DataService.instance.UsersRef.queryOrdered(byChild:"Nickname").queryEqual(toValue: "kai1004pro").observe(.value, with: { (snapshot) in

        if (snapshot.value is NSNull) {
            print("not found")
        } else {
            print("found")
            print(snapshot.value)
        }




    })

这是我的 json 树:

This is my json tree:

Optional({
g50X0FvEsSO4L457v7NzS3dAABl1 =     {
    "User Profile" =         {
        Birthday = "Sep 20, 1992";
        Gender = Female;
        Nickname = kai1004pro;
        UserUID = g50X0FvEsSO4L457v7NzS3dAABl1;
        emailAddress = "[e-mail]";
        isFollow = 0;
        isFriend = 0;
    };
};
})

这是安全规则:

"rules": {
".read": true,
".write": "auth != null",
"Users": {
  ".read": true,
  ".write": "auth != null",
  ".indexOn": ["Nickname", "User Profile"]
    }
  }
}

推荐答案

修改您的 JSON 树以包含一个单独的节点 active_usernames，以便在任何时候添加每个用户的用户名您创建新用户，每当您的用户修改其用户名时进行修改...

Modify your JSON tree to include a separate node active_usernames, in that add username of every user whenever you create new user, modify whenever your user modify its username...

myApp:{
  users:{
    uid1:{....},
    uid2:{....},
    uid3:{....},
    uid4:{....},
  }
active_usernames :{
    uid1username : "true",
    uid2username : "true",
    uid3username : "true",
    uid4username : "true"
    }
}

要检查您的用户名是否已经存在:-

To check your if username already exists:-

//Checking username existence
FIRDatabase.database().reference().child("active_usernames").child(self.enteredUsername.text!).observeSingleEvent(of: .value, with: {(usernameSnap) in

        if usernameSnap.exists(){
        //This username already exists

        }else{

        //Yippee!.. This can be my username
        }

    })

还要通过操纵安全规则，将您的安全规则更改为对所有人(ONLY READABLE)可读.

Also change your security rules to be readable (ONLY READABLE) to all, by manipulating the security rules.

{rules :{

   active_usernames : {

      ".read" : "true",
      ".write" : "auth != null"

      }
    }
   }

PS:- enteredUsername 是您输入用户名的文本字段.

PS:- enteredUsername is the textField in which you enter your username.

建议:-将校验码保留在textField的didChangeEditing事件中(为了更好的用户体验！)

Suggestion:- keep the checking code inside didChangeEditing event of the textField(For better user experience.!)

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