motion jpeg

import UIKit

class ViewController: UIViewController, URLSessionDataDelegate {
    var cameraImageView: UIImageView!
    
    var session: URLSession!
    var request: URLRequest!
    var imageData = Data()
    let source = "http://cctvn01.freeway.gov.tw/vStream.php?pm=164,A44,19"
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        cameraImageView = UIImageView()
        cameraImageView.contentMode = .scaleAspectFit
        cameraImageView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(cameraImageView)
        
        setupConstraints()
        
        session = URLSession(configuration: URLSessionConfiguration.default,
                             delegate: self,
                             delegateQueue: nil)
        
        request = URLRequest(url: URL(string: source)!)
        
        start(with: request)
    }
    
    func setupConstraints() {
        cameraImageView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
        cameraImageView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
        cameraImageView.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.5).isActive = true
        view.trailingAnchor.constraint(equalTo: cameraImageView.trailingAnchor).isActive = true
    }
    
    func start(with request: URLRequest) {
        let dataTask = session.dataTask(with: request)
        
        dataTask.resume()
    }
    
    func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
        let startMarker = Data(bytes: [0xff, 0xd8])
        let startMarkerRange = data.range(of: startMarker, options: .anchored, in: data.startIndex..<data.endIndex)
        
        if imageData.isEmpty && startMarkerRange == nil {
            dataTask.cancel()
            return
        }
        
        guard let range = startMarkerRange, !imageData.isEmpty else {
            imageData.append(data)
            return
        }
        
        let rest = data.subdata(in: data.startIndex..<range.lowerBound)
        
        imageData.append(rest)
        
        let image = UIImage(data: imageData)
        
        imageData = data.subdata(in: range.lowerBound..<data.endIndex)
        
        DispatchQueue.main.async {
            self.cameraImageView.image = image
        }
    }
    
    func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
        if error == nil {
            start(with: request)
        }
    }
}