Example of fetching Mapped Object using Realm and Alamofire

ExampleModel.swift

import UIKit
import ObjectMapper
import RealmSwift

class Example: Object, Mappable, Meta {
    
    dynamic var id: Int = 0
    dynamic var title: String = ""
    dynamic var author: String = ""
    dynamic var genre: String = ""
    
    //Realm
    override static func primaryKey() -> String? {
        return "id"
    }
    
    //Object Mapper
    required convenience init?(_ map: Map) {
        self.init()
    }
    
    func mapping(map: Map) {
        id <- map["id"]
        title <- map["title"]
        author <- map["author"]
        genre <- map["genre"]
    }
    
    //Meta
    static func url() -> String {
        return "https://demo7589466.mockable.io/books"
    }
}

FetchData.swift

import Foundation
import Alamofire
import AlamofireObjectMapper
import RealmSwift
import ObjectMapper

class FetchData {

    typealias SuccessCallback = () -> Void
    typealias FailCallback = (NSError) -> Void
  
    static func fetchSomeData <T:Object where T:Mappable,T:Meta> (type:T.Type, success: SuccessCallback, fail: FailCallback) {
        Alamofire.request(Method.GET, type.url())
            .responseArray { (response: Response<[T], NSError>) in
                switch response.result {
                case .Success(let items):
                    autoreleasepool{
                        do {
                            let realm = try Realm()
                            try realm.write {
                                for item in items {
                                    realm.add(item, update: true)
                                }
                            }
                        } catch let error as NSError {
                            fail(error)
                        }
                    }
                    success()
                case .Failure(let error):
                    fail(error)
                    break
                }
        }
    }
}

MetaProtocol.swift

protocol Meta {
    static func url() -> String
}

UsageExample.swift

FetchData.doSomeWork(Books.self, success: {
            print("success")
            }, fail: { (error) in
                print(error)
        })