image loading and disk saving using alamofire

ImageViewExtension.swift

//
//  ImageExt.swift
//  Dabbagul
//
//  Created by Hemant Singh on 06/05/17.

import Foundation
import Alamofire
extension UIImageView {
    var documentsUrl: URL {
        return FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
    }
    func setImage(from url: URL, withPlaceholder placeholder: UIImage? = nil) {
        if let filename = url.absoluteString.components(separatedBy: "/").last {
            if let img = load(fileName: filename) {
                DispatchQueue.main.async {
                    self.image = img
                    return
                }
            }
            else{
                 self.image = placeholder
                Alamofire.request(url.absoluteString).responseData { (res) in
                    if let data = res.data {
                        let image = UIImage(data: data)
                        if image != nil {
                            // Save image.
                            self.save(image: image!, filename: filename)
                            DispatchQueue.main.async {
                                self.image = image
                            }
                        }
                    }
                }
            }
            }
    }
    private func save(image: UIImage, filename : String) {
        let fileURL = documentsUrl.appendingPathComponent(filename)
        if let imageData = UIImageJPEGRepresentation(image, 1.0) {
            try? imageData.write(to: fileURL, options: .atomic)
        }
        print("Error saving image")
    }
    private func load(fileName: String) -> UIImage? {
        let fileURL = documentsUrl.appendingPathComponent(fileName)
        do {
            let imageData = try Data(contentsOf: fileURL)
            return UIImage(data: imageData)
        } catch {
            print("Error loading image : \(error)")
        }
        return nil
    }
}