如何使用 swift 从 firebase 中的 JSON 文件中获取电子邮件 ID

JSON 图像 https://i.stack.imgur.com/V7yZA.png我想查询如下：如果我提供电子邮件，那么我必须获取 ID。目前我可以获取电子邮件或 ID，但我需要以下示例的解决方案。

例如 1）如果我给[email protected] /cdn-cgi/l/email-protection那么我需要它的 ID123.

我怎样才能快速实现这一目标？

这是我的JSON file:

{
   "ID": 123,
   "Membership": 1234,
   "title": "Mr.",
   "firstname": "kumar",
   "lastname": "sandeep",
   "email": "[email protected] /cdn-cgi/l/email-protection",
   "membrshipstatus": "Active",
   "volunteer": "Yes",
   "creationDate": "2016-12-27 "
 },

{
   "ID": 452,
   "Membership": 4531,
   "title": "Mr.",
   "firstname": "kumar",
   "lastname": "sandeep",
   "email": "[email protected] /cdn-cgi/l/email-protection",
   "membrshipstatus": "Active",
   "volunteer": "Yes",
   "creationDate": "2016-11-17 "
 },

这是我的Swift code:

    import UIKit
    import Firebase
    import FirebaseAuth

    class ViewController: UIViewController {

        @IBOutlet weak var emailofUser: UITextField!
        @IBOutlet weak var passwordofUser: UITextField!
        var ref:FIRDatabaseReference! //created a variable ref of type firebase database reference
        var databaseHandle:FIRDatabaseHandle? //to handle to database listener like to stop or start it


        var postdata = [String]?()
        var postall = [[String:String]]()


        override func viewDidLoad() {
            super.viewDidLoad()

            //set firebase reference
            ref = FIRDatabase.database().reference()

ref.child("1").child("email").observeEventType(.Value, withBlock: { snapshot in

            let emailid = snapshot.value as? String

            print(emailid)
        })

ref.child("1").child("ID").observeEventType(.Value, withBlock: { snapshot1 in

            let userID = snapshot1.value as? Int

            print(userID)
        })

            ref.queryOrderedByValue().observeEventType(.ChildAdded, withBlock: { snapshot2 in
                if let parentname = snapshot2.value as? Int {
                    print("The \(snapshot2.key) dinosaur's score is \(parentname)")
                }
            })
        }
    }

与此 JSON 图像相关的 Swift 代码：

override func viewDidLoad() {
        super.viewDidLoad()



            //set firebase reference
        ref = FIRDatabase.database().reference()

        let userRef = ref.child("1")

        //let queryRef = userRef.queryOrderedByChild("email").queryEqualToValue("[email protected] /cdn-cgi/l/email-protection")


        userRef.queryOrderedByChild("email").queryEqualToValue("[email protected] /cdn-cgi/l/email-protection").observeEventType(.Value, withBlock: { snapshot in

            for child in snapshot.children{

            let snap = child as! FIRDataSnapshot

                let userDict = snap.value as! [String:Any]

                let userId = userDict["ID"]
                let lastname = userDict["lastname"]
                print("\(userId!)  \(lastname!)")


            }
                    })

一般来说，您应该使用用户的 uid 在用户节点中存储数据。假设您的用户节点名为 /users... 像这样

users
  uid_0
   "ID": 123,
   "Membership": 1234,
   "title": "Mr.",
   "firstname": "kumar",
   "lastname": "sandeep",
   "email": "[email protected] /cdn-cgi/l/email-protection"
  uid_1
   "ID": 452,
   "Membership": 4531,
   "title": "Mr.",
   "firstname": "kumar",
   "lastname": "sandeep"
   "email": "[email protected] /cdn-cgi/l/email-protection"

这是获取您所询问的数据的查询

let usersRef = ref.child("users")
let queryRef = usersRef.queryOrdered(byChild: "email")
                       .queryEqual(toValue: "[email protected] /cdn-cgi/l/email-protection")
queryRef.observeSingleEvent(of: .value, with: { (snapshot) in

     for child in snapshot.children {
          let snap = child as! FIRDataSnapshot
          let userDict = snap.value as! [String: Any]
          let userId = userDict["ID"]
          let lastname = userDict["lastname"]
          print("\(userId!)  \(lastname!)")
      }
})

结果打印：

123  sandeep