Require a dictionary to contain certain values (Swift) - ios

Question

I am creating a model for saving user data to a Firestore database and am initializing it with a dictionary. Depending on what fields I want to update, I put those values in the dictionary so that the user model only contains certain fields and will therefore only update those fields in my database. However, I want to somehow require that certain fields are provided in certain use cases.
* Below example is a very simplified version of what I am trying to do *
For example: if I am saving a new user, I want to make sure that I include a name, a profile image, and a description. But if I simply want to update a field, then I don't want to require that all those fields are included
I am 99% certain I am attacking this the wrong way, so any help is appreciated.
My Current User Model:
struct FirestoreUser {
var id: String
var name: String?
var profileImage: String?
var dictionary: [String: Any]
init(dictionary: [String: Any]) {
self.id = dictionary["id"] as! String
self.name = dictionary["name"] as? String
self.profileImage = dictionary["profileImage"] as? String
self.dictionary = dictionary
}
}
// MARK: Firestore functions
extension FirestoreUser {
typealias Handler = ((Error?) -> Void)?
func saveNewFirestoreUser(then handler: Handler = nil) {
// make sure all necessary variables are set
// if they aren't all set, something went wrong
guard let _ = name, let _ = profileImage else { return }
let firestore = Firestore.firestore()
let ref = firestore.collection("users").document(id)
ref.setData(dictionary) { (error) in
if let error = error {
handler?(error)
}
handler?(nil)
}
}
}

Answer 1

Construct struct with optional value and pass nil as the parameter which you don't want to update.
You can use the below extension to convert struct to dictionary later.
struct FirestoreUser: Codable {
var id: String
var name: String?
var profileImage: String?
}
extension Encodable {
var dictionary: [String: Any]? {
guard let data = try? JSONEncoder().encode(self) else { return nil }
return (try? JSONSerialization.jsonObject(with: data, options: .allowFragments)).flatMap { $0 as? [String: Any] }
}
}
Use -
let test = FirestoreUser(id: "01", name: "Abhinav", profileImage: nil)
print(test.dictionary)
Output -
["name": Abhinav, "id": 01]

Answer 2

In realtime database use updateChildValues instead of setValue if you just want to update the child. I believe there's something equivalent in firestore.
Answer for realtime database:
Update
self.ref.child("users/\(user.uid)/username").setValue(username)
Set new data
let key = ref.child("posts").childByAutoId().key
let post = ["uid": userID,
"author": username,
"title": title,
"body": body]
let childUpdates = ["/posts/\(key)": post,
"/user-posts/\(userID)/\(key)/": post]
ref.updateChildValues(childUpdates)
Answer for firestore:
Just read the documentation for firestore, use updateData instead of addDocument:
let washingtonRef = db.collection("cities").document("DC")
// Set the "capital" field of the city 'DC'
washingtonRef.updateData([
"capital": true
]) { err in
if let err = err {
print("Error updating document: \(err)")
} else {
print("Document successfully updated")
}
}
Set/Add new data
// Add a new document with a generated id.
var ref: DocumentReference? = nil
ref = db.collection("cities").addDocument(data: [
"name": "Tokyo",
"country": "Japan"
]) { err in
if let err = err {
print("Error adding document: \(err)")
} else {
print("Document added with ID: \(ref!.documentID)")
}
}
So rule of thumb is to only pass in the field that you need to update instead of the whole collection/dictionary.