如何在 Firestore 中读取当前用户配置文件

Question

I am working on my first IOS app using Firestore. I am successfully retrieving all user documents or a specific document with a document name from the "users" collection. But as soon as I want to query the currentUsers documents I have trouble. I need the data for a user profile viewController.

I can query a specific document and print it with this code:

func loadUserData() {
    let userDocumentRef = Firestore.firestore().collection("users").document(
        "6tIzsXgbOMDIFpdgR18i")
    
    userDocumentRef.getDocument { (document, error) in
        if let document = document, document.exists {
            let userData = document.data().map(String.init(describing: )) ?? "nil"
            print("Document data: \(userData)")
        } else {
            print("document does not exist")
            
        }
    }
}

But as soon as I try to get the currentUsers document with this code, then I get the error that "document does not exist":

func currentUserData() {
    let userID : String = (Auth.auth().currentUser?.uid)!
    let userRef = Firestore.firestore().collection("users").document(userID)
    userRef.getDocument { (document, error) in
        if let document = document, document.exists {
            let userData = document.data().map(String.init(describing: )) ?? "nil"
            print("Document data: \(userData)")
        } else {
            print("document does not exist")
            
        }
    }
}

Here is a screenshot of the users collection in Firestore. Screenshot of Firestore users collection

I just simply cannot figure out what I am doing wrong, so any help is appreciated.

Answer 1

It seems like there is an issue when mapping the document. Here is how you can map data from Firestore to Swift:

struct UserProfile: Codable, Identifiable {
  @DocumentID var id: String?
  var userId: String
  var firstName: String
  // ... other attributes
}

func currentUserData() {
  // Note: this is unsafe, please use an auth state change listener instead
  // Also, please try to avoid using force unwrap - your app will crash if the attribute is nil
  let userID : String = (Auth.auth().currentUser?.uid)!

  let userRef = Firestore.firestore().collection("users").document(userID)
  userRef.getDocument { (document, error) in
    if let document = document, document.exists {
      let userData = document.data(as: UserProfile.self)
      print("Document data: \(userData)")
    } else {
      print("document does not exist")
    }
  }
}

Here is how to set up an auth state change listener: https://firebase.google.com/docs/auth/ios/start#listen_for_authentication_state