Read MJPEG int CGImage using Swift4, URLSession, OSX

main.swift

//
//  main.swift
//  MJPEGreader
//
//  Created by michal on 17/11/2017.
//  Copyright © 2018 michal. All rights reserved.
//

import Foundation

let configuration = URLSessionConfiguration.ephemeral

var urlComponents = URLComponents(string: "http://192.168.0.27:8080")!
urlComponents.query = "action=stream"
let url = urlComponents.url!

enum MjpegReadError: Error {
    case badResponse, parseImage
}

class MjpegRead: NSObject, URLSessionDelegate, URLSessionDataDelegate {
    
    let startMarker: Data = Data(bytes: [0xFF, 0xD8])
    let endMarker: Data = Data(bytes: [0xFF, 0xD9])
    
    var buffer: Data = Data()
    
    let configuration = URLSessionConfiguration.ephemeral
    var session: URLSession?
    var task: URLSessionDataTask?
    var handler: ((CGImage?, MjpegReadError?)->())?
    
    func readStream(_ url: URL, handler: @escaping (CGImage?, MjpegReadError?)->()) {
        self.handler = handler
        session = URLSession.init(configuration: configuration, delegate: self, delegateQueue: nil)
        task = session?.dataTask(with: url)
        task?.resume()
    }
    
    func stopStream() {
        task?.cancel()
        task = nil
    }
    
    // MARK: Session Delegates
    
    func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
  
        guard let response = dataTask.response as? HTTPURLResponse, response.statusCode == 200 else {
            handler?(nil, .badResponse)
            return
        }
        if data.range(of: startMarker) != nil {
            print("started new frame")
            buffer = Data() // clean up buffer
        }
        buffer.append(data)
        
        // frame has ended if not nil
        if data.range(of: endMarker) != nil {
            print ("finished frame")
            let frame = parseFrame(buffer)
            handler?(frame, nil)
        }
    }
    
    private func parseFrame(_ data: Data) -> CGImage? {
        guard let imgProvider = CGDataProvider.init(data: data as CFData) else {
            handler?(nil, .parseImage)
            return nil
        }
        guard let image = CGImage.init(jpegDataProviderSource: imgProvider, decode: nil, shouldInterpolate: true, intent: CGColorRenderingIntent.defaultIntent) else {
            handler?(nil, .parseImage)
            return nil
        }
        return image
    }
}

let mjpegRead = MjpegRead()
mjpegRead.readStream(url) { image, error in
    if let error = error {
        print(error.localizedDescription)
    }
    if let image = image {
        print("image:", image.width, image.height)
    }
}

dispatchMain()

Thanks for this, you saved my life. Worked perfectly.