How to parse data from firebase and then save it within a model. Swift3 MVC format - swift

Question

I have a user class within my firebaseDB. Its what you would expect a flat file DB would look like: users->UID->profile->key/values. I am trying to implement best practice within my code so I want the data to be handled by the User model in my Xcode project. How would I go about parsing the data and saving it as class variables within my model.
class User {
private var _username: String
private var _uid: String
var uid: String {
return _uid
}
var username: String {
return _username
}
init (uid: String, username:String) {
self._uid = uid
self._username = username
}
func getUserData() {
DataService.ds.REF_USERS.observeSingleEvent(of: .value, with: { (snapshot) in
if let users = snapshot.value as? Dictionary<String, Any>{
for (key, value) in users { // We use the for in loop to iterate through each key/value pair in the database which is stored as a dictionary.
if let dict = value as? Dictionary<String, Any> { // This gets us inside the user ID
if let profile = dict["profile"] as? Dictionary<String, Any> { // This gets us inside the profile
if let username = profile["username"] as? String {
self._uid = key // Stores the UID of the user as the key.
self._username = username
} else {
let username = profile["name"] as? String
self._uid = key
self._username = username!
}
}
}
}
}
This is what I am trying to do but I am lost as to how I would actually store the data values within the class. FYI: username is an attribute under profile.

Answer 1

You are currently looping through the entire list of users in the database and assigning the User properties repeatedly, overwriting the value from the previous loop cycle.
In order to get the correct user values assigned, you will need a way of knowing the correct path to the values. I would suggest saving the users using their assigned Firebase UID.
If you know the correct UID to look up you can then implement the following code:
func getUserData() {
DataService.ds.REF_USERS.child(_uid).child("profile").observeSingleEvent(of: .value, with: { (snapshot) in
guard let profileDict = snapshot.value as? [String: Any] else {
print("Error fetching user")
return
}
self._username = profileDict["username"] as? String ?? profileDict["name"] as! String
})
}
The way that "username" is force unwrapped in your original code doesn't appear safe but I'm assuming you are certain that it will work out. Otherwise the following line should be changed to safely unwrap the optional:
self._username = profileDict["username"] as? String ?? profileDict["name"] as! String