want to fetch userdata from firebase into a dictionary

Question

I hope you could help me: I try to fetch userdata from a firebase database into a user class and call "setValuesForKeys". I do understand that my class properties have to be exactly the same as in the firebase dictionary, but I've got the error "this class is not key value coding-compliant for the key city."

func fetchUsers(){
    Database.database().reference().child("users").observe(.childAdded, with: { (snapshot) in
        if let usersDictionary = snapshot.value as? [String: String] {
            let users = Userdata()
            users.setValuesForKeys(usersDictionary)
        }
    }, withCancel: nil)
}

And my user class is

class Userdata: NSObject {
    var email: String?
    var password: String?
    var firstname: String?
    var lastname: String?
    var street: String?
    var streetno: String?
    var zipcode: String?
    var city: String?
    var phone: String?  }

The snapshot from firebase looks like

Snap (ndLBXXX75Oe9Y1PXrqfISL8A4v82) {
city = Washington;
email = "1@a.com";
firstname = Andre;
lastname = Doe;
password = xxxxxx;
phone = "";
street = "Mainstreet";
streetno = 1;
zipcode = 11111;

}

And the dictionary from the database looks like

["city": Washington, "firstname": Andre, "lastname": Doe, "email": 1@a.com, "password": xxxxxx, "streetno": 1, "phone": , "street": Mainstreet, "zipcode": 11111]

I have a solution so far by using:

users.city = dictionary["city"]

My question / problem: I do want to understand the problem behind the error message "this class is not key value coding-compliant for the key city." because the key at the class and in the firebase snapshot looks like the same.

This error is because you are trying to use KVC. Read about KVC usage here https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/KeyValueCoding/. Dictionary doesn't have properties for keys city, email... That's why you see the error. You can loop through all keys from dictionary and use user.setValue(dictionary[key], forKey: key) — Stas Volskiy, Aug 16 '17 at 15:09
Check out an answer of mine that makes converting snapshots to custom classes easy - https://stackoverflow.com/a/38154998/2019221 — Callam, Aug 16 '17 at 20:55
@StasVolskiy thanks for your answer and your solution with a loop. It does work. My solution is: `user.firstname = usersDictionary["firstname"]` I've read this https://developer.apple.com/documentation/objectivec/nsobject/1417515-setvaluesforkeys and i thought that i could take the dictonary-keys and match them with my class properties. — andre_hold, Aug 17 '17 at 11:40

score 0 · Accepted Answer · edited Feb 21 '18 at 16:14

Working solution: I had to extend my user class. Now, the whole user class looks like:

Here is the code :

 import Foundation

    class UserData: NSObject {
        var id: String?
        var email: String?
        var password: String?
        var salutation: String?
        var degree: String?
        var firstname: String?
        var lastname: String?
        var street: String?
        var streetno: String?
        var zipcode: String?
        var city: String?
        var phone: String?
        var profileImage: String?

    init(dictionary: [String: Any]) {
        self.city = dictionary["city"] as? String
        self.id = dictionary["id"] as? String
        self.email = dictionary["email"] as? String
        self.salutation = dictionary["salutation"] as? String
        self.degree = dictionary["degree"] as? String
        self.firstname = dictionary["firstname"] as? String
        self.lastname = dictionary["lastname"] as? String
        self.password = dictionary["password"] as? String
        self.phone = dictionary["phone"] as? String
        self.street = dictionary["street"] as? String
        self.streetno = dictionary["streetno"] as? String
        self.zipcode = dictionary["zipcode"] as? String
        self.profileImage = dictionary["profileImage"] as? String

    }
}

want to fetch userdata from firebase into a dictionary

1 Answers1