Swift/Firestore：完成不会被调用

Question

I'm trying to create a "Profile" collection in Firestore in order to store more data on my users than just their email/name. I'm stuck with creating this document and uploading the profile picture they choose (as an URL).

Here is the function called when they click on the "Register" button:

func register() {
            Auth.auth().createUser(withEmail: self.email, password: self.pass) { (res, err) in
                if err != nil {
                    self.error = err!.localizedDescription
                    self.alert.toggle()
                    return
                }
                // Success registering a new user
                guard let userUID = res?.user.uid else { return }

                uploadImageToFirestore(id: userUID, image: myImage) {
                    print("SUCCESS")
                    self.imageURL = downloadImageFromFirestore(id: userUID)
                    self.createUserDocument(id: userUID, imgURL: self.imageURL)
                }
        }

First step is uploading picture on Firebase Storage using the uploadImageToFirestore function and I tried using a completion handler to wait before calling the next 2 functions:

    func uploadImageToFirestore(id: String, image: UIImage, completion: () -> Void) {
    let storageRef = storage.reference().child("images/\(id)/image.jpg").putData(image.jpegData(compressionQuality: 0.35)!, metadata: nil) { (_, err) in
        if err != nil {
            print((err?.localizedDescription)!)
            return
        }
        print("Success uploading picture to Firestore")
    }
}

Second step is downloading the newly uploaded image on Firebase Storage to get the URL:

    func downloadImageFromFirestore(id: String) -> String {
    let storageRef = storage.reference().child("images/\(id)/image.jpg")
    storageRef.downloadURL { url, error in
        if error != nil {
            print("DEBUG: \((error?.localizedDescription)!)")
            return
        }
        print("Success downloading picture from Firestore")
        self.imageURL = "\(url!)"
    }
    return self.imageURL
}

Third step is creating the Profile collection in Firestore with the ImageURL:

    func createUserDocument(id: String, imgURL: String) {
    db.collection("profiles").document(id).setData([
        "name": name,
        "surname": surname,
        "email": email,
        "shelter": isMember == true ? shelters[selectedShelter] : shelters[0],
        "photoURL": imgURL,
        "reputation": 0,
        "uuid": id
    ])
    { err in
        if let error = err {
            print("Error ading document: \(error)")
        } else {
            print("New profile document created in Firestore")
        }
    }
}

THE PROBLEM

The problem I face is that in my "Register" function, the completion block of uploadImageToFirestore is never called, thus the function createUserDocument neither.

Is this the best way to achieve what I want (aka creating a profile document with the imageURL of the picture they just choose while registering)? Why is my completion block not called? (I don't see the "SUCCESS" printed in my console).

Thank you for your help!

Kind regards, Jihaysse

Answer 1

You need to call the completion handler closure that you are passing to uploadImageToFirestore .

You should probably also pass the error , if any, so that you can handle it.

func uploadImageToFirestore(id: String, image: UIImage, completion: (Error?) -> Void) {
    let storageRef = storage.reference().child("images/\(id)/image.jpg").putData(image.jpegData(compressionQuality: 0.35)!, metadata: nil) { (_, err) in
        completion(err)
    }
}