如何在Swift中从Firebase数据库检索变量

Question

我试图简单地读入结构如下所述的数据库。 我正在尝试读取用户的“ userType”，并在下面的if语句中使用它。 任何帮助表示赞赏！

SWIFT代码：

// Create firebase reference and link to database
var dataRef : DatabaseReference?
dataRef = Database.database().reference()
let userID = Auth.auth().currentUser!.uid // Get the User's ID

// Gather user's type (Customer or Company)
/*Use this space to gather the user's type into some variable named currUserType*/


if (currUserType == "Customer"){
    self.performSegue(withIdentifier: "LoginToCustomer", sender: self)
    print("User: " + userID + " has been signed in!")
}
else if (currUserType == "Company"){
    self.performSegue(withIdentifier: "LoginToHost", sender: self)
}
else{
    self.showMessage(alertTitle: "Error",
                                 alertMessage: "Please report the following error with a description of what lead to to the error.",
                                 actionTitle: "Dismiss")
}

数据库结构：

"Users" : {
"ZFH0lFe1fIb5bwSO2Q95ektD33L2" : {
  "email" : "cust@test.com",
  "userType" : "Customer"
}

Answer 1

1. 首先像我在下面那样拿裁判：

让dbRef = Database.database（）。reference（）。child（“ Users”）

2. 然后像我在下面创建的那样创建模型：

class Users {var email：String？ var userType：字符串？

init(email: String, userType: String) {
    self.email = email
    self.userType = userType
}

}

3. 然后像我在下面创建的那样创建完成处理程序：

 func getUsersData(handler: @escaping (_ usersArray: [Users]) -> ()) { 

var usersArray = [Users]()

dbRef.observe(.value) { (datasnapshot) in

    guard let usersnapshot = datasnapshot.children.allObjects as? [DataSnapshot] else { return }

    for user in usersnapshot {
        let email = user.childSnapshot(forPath: "email").value as! String
        let userType = user.childSnapshot(forPath: "userType").value as! String

        let userObj = Users(email: email, userType: userType)
        usersArray.append(userObj)
    }
    handler(usersArray)
}

}

4. 只需调用此函数即可返回整个用户数组。

刷新https://firebase.google.com/docs/database/ios/read-and-write#reading_and_writing_data