打印 Firebase 快照中具有特定子项和特定词的所有用户？

Question

"users" : {
  "1ZWT7FAE2qThNQfBj7tbMO7BnMo1" : {
    "Coordinates" : {
       "latitude" : 50.054738,
       "longitude" : 8.226809826085624
    "Email" : mark@gmail.com

假设您有一个所有用户的子项（“电子邮件”）。现在你制作一个快照来检查所有用户的所有电子邮件。登录用户有一个@gmail 帐户。您打印所有与登录用户具有相同电子邮件域的用户，例如@gmail。可能像下面这样需要弄清楚粗线的地方

refArtists.observe(DataEventType.value，其中：{快照在

if snapshot.childrenCount>0{
    
    self.users.removeAll()
    
    for users in snapshot.children.allObjects as! [DataSnapshot] {
        
        if users.key != thisUsersUid {
            print("userskey",users.key)
            
            let usersObject = users.value as? [String: AnyObject]
            let usersEmail = peopleObject?["Email"] as? String
            ......
            let A = users.childSnapshot(forPath: “Email)
            **if  A@ = the @ of  thisUsersUid** {
                
                let u = Userx(Email: peopleEmail, .........)
                
                self.users.append(u)
                
            } else {
                print ("w")
            }
        } else {
            print ("a")
            
        }
    }}
}   
}
})

以下是我实际创建完整电子邮件的方式。这是在第一个答案之后添加的：

    @IBAction func signInPressed(_ sender: Any) {
    
    Auth.auth().createUser(withEmail: (emailField.text ?? ""), password: (passwordField.text ?? ""))  { (user, error) in
        if let _eror = error {
            //something bad happning
            print(_eror.localizedDescription )
            let alert = UIAlertController(title: "Error", message: "Invalid Entry or Duplicate.", preferredStyle: UIAlertController.Style.alert)
            let action = UIAlertAction(title: "Ok", style: .default, handler: nil)
            alert.addAction(action)
            self.present(alert, animated: true, completion: nil)
            
        }else{
            //user registered successfully
            print(user as Any)
            if let userID = user?.user.uid
            {
                KeychainWrapper.standard.set((userID), forKey: "uid")
                
                let databaseRef = Database.database().reference()
                
                databaseRef.child("people").child(userID).child("users").setValue(self.emailField.text!)
                databaseRef.child("people").child(userID).child("postID").setValue(userID)
                
                self.performSegue(withIdentifier: "tohome", sender: nil)
            }
            
        }
    }
}

Answer 1

Firebase 不提供真正的部分字符串搜索 - 有方法可以搜索字符串的前面但无法搜索字符串的后面，例如您可以在此列表中搜索名字 steve

frank@mac.com
steve@gmail.com
larry@mac.com

但您无法搜索 gmail.com。

预先处理的方法是，当用户最初输入他们的电子邮件地址时，将其分解为代码中的各个组件；用户名，然后是域名，并将它们作为两个子注释存储在 Firebase

中

 steve  @  gmail.com
  ^          ^
username   domain

那么您搜索 gmail.com 就很容易了。

您的用户节点现在看起来像这样

firebase
   users
      uid_0
         email_name: "frank"  //the logged in user
         email_domain: "mac.com"
      uid_1
         email_name: "steve"
         email_domain: "gmail.com"
      uid_2
         email_name: "larry"
         email_domain: "mac.com"

然后获取与登录用户具有相同域的所有用户，这是 Firebase 代码。请注意，我们获取所有匹配的用户，然后从快照中删除当前用户。

func queryForDomainMatch() {
    let myDomain = "mac.com" //read from my users node
    let myUid = "uid_0" //the users uid - user 'frank' in this case
    let ref = self.ref.child("users") //self.ref points to MY firebase
    let query = ref.queryOrdered(byChild: "email_domain").queryEqual(toValue: myDomain)
    query.observeSingleEvent(of: .value, with: { snapshot in
        var allUsers = snapshot.children.allObjects as! [DataSnapshot]
        if let index = allUsers.firstIndex(where: { [=13=].key == myUid } ) {
            allUsers.remove(at: index) //remove the current user
        }
        for userSnap in allUsers {
            let name = userSnap.childSnapshot(forPath: "email_name").value as! String
            print(name)
        }
    })
}

输出将是匹配节点的名称

larry

编辑

要拆分电子邮件，只需对字符串使用 Swift 拆分功能。它将字符串分成用户名和域的数组。像这样

let email = "jay@mac.com"
let components = email.split(separator: "@")
components.forEach { print([=15=]) }

和输出

jay
mac.com

打印 Firebase 快照中具有特定子项和特定词的所有用户？

Printing all users in a Firebase Snapshot that have a specific Child with a Specific word?

swift

firebase

firebase-realtime-database

snapshot