A simple Swift protocol for Firebase objects with default save() and delete() implementations.

FirebaseType.swift

//
//  FirebaseType.swift
//

import Foundation
import Firebase

protocol FirebaseType {
    
    // properties
    var identifier: String? { get set }
    var endpoint: String { get }
    var secondaryEndpoints: [String]? { get }
    var jsonValue: [String: AnyObject] { get }
    
    // initializers
    init?(json: [String: AnyObject], identifier: String)
    
    // functions
    mutating func save()
    func delete()
}

extension FirebaseType {
    
    mutating func save() {
        
        // save to primary endpoint
        
        var endpointBase: Firebase
        
        if let childID = self.identifier {
            endpointBase = FirebaseController.base.childByAppendingPath(endpoint).childByAppendingPath(childID)
        } else {
            endpointBase = FirebaseController.base.childByAppendingPath(endpoint).childByAutoId()
            self.identifier = endpointBase.key
        }
        
        endpointBase.updateChildValues(self.jsonValue)
        
        // save to any secondary endpoints
        if let secondaryEndpoints = secondaryEndpoints {
            
            for endpoint in secondaryEndpoints {
                let secondaryEndpointBase = FirebaseController.base.childByAppendingPath(endpoint).childByAppendingPath(self.identifier)
                secondaryEndpointBase.setValue(self.identifier)
            }
        }
    }
    
    func delete() {
        
        let endpointBase: Firebase = FirebaseController.base.childByAppendingPath(endpoint).childByAppendingPath(self.identifier)
        
        endpointBase.removeValue()
    }
}