Gists supporting the "Encapsulating the User" blog post.

encapsulating user code_1.swift

//
//  ViewController.swift
//
//  Created by Daniel Tartaglia on 1/27/17.
//  Copyright © 2017 Daniel Tartaglia. MIT License.
//

import UIKit

class ViewController: UIViewController
{
    @IBOutlet weak var avatarView: UIImageView!

    var api: API!

    @IBAction func changeAvatar(_ sender: UITapGestureRecognizer) {
        let controller = UIImagePickerController()
        controller.delegate = self
        let cameraAction: UIAlertAction? = !UIImagePickerController.isSourceTypeAvailable(.camera) ? nil : UIAlertAction(title: "Camera", style: .default) { _ in
            controller.sourceType = .camera
            self.present(controller, animated: true, completion: nil)
        }
        let photobinAction: UIAlertAction? = !UIImagePickerController.isSourceTypeAvailable(.photoLibrary) ? nil : UIAlertAction(title: "Photos", style: .default) { _ in
            controller.sourceType = .photoLibrary
            self.present(controller, animated: true, completion: nil)
        }
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)

        let alert = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
        if let cameraAction = cameraAction {
            alert.addAction(cameraAction)
        }
        if let photobinAction = photobinAction {
            alert.addAction(photobinAction)
        }
        alert.addAction(cancelAction)
        if let popoverPresentationController = alert.popoverPresentationController,
            let view = sender.view {
            popoverPresentationController.sourceView = view
            popoverPresentationController.sourceRect = view.bounds
        }
        present(alert, animated: true, completion: nil)
    }

}

extension ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        let image = (info[UIImagePickerControllerEditedImage] as? UIImage) ?? (info[UIImagePickerControllerOriginalImage] as? UIImage)
        if let data = image.flatMap({ UIImageJPEGRepresentation($0, 0.8)} ) {
            api.upload(avatar: data) { [weak self] result in
                switch result {
                case .success:
                    self?.avatarView.image = image
                    self?.dismiss(animated: true, completion: nil)
                case .failure(let error):
                    self?.dismiss(animated: true) {
                        let alert = UIAlertController(title: "Error", message: error.localizedDescription, preferredStyle: .alert)
                        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
                        self?.present(alert, animated: true, completion: nil)
                    }
                }
            }
        }
    }

    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        dismiss(animated: true, completion: nil)
    }
}