Reachability in Swift 4

Reachability.swift

//
//  Reachability.swift
//  
//
//  Created by NETBIZ on 12/10/18.
//  Copyright © 2018 Netbiz.in. All rights reserved.
//


import Foundation
import SystemConfiguration

public class Reachability {
    
    class func isConnectedToNetwork() -> Bool {
        
        var zeroAddress = sockaddr_in(sin_len: 0, sin_family: 0, sin_port: 0, sin_addr: in_addr(s_addr: 0), sin_zero: (0, 0, 0, 0, 0, 0, 0, 0))
        zeroAddress.sin_len = UInt8(MemoryLayout.size(ofValue: zeroAddress))
        zeroAddress.sin_family = sa_family_t(AF_INET)
        
        let defaultRouteReachability = withUnsafePointer(to: &zeroAddress) {
            $0.withMemoryRebound(to: sockaddr.self, capacity: 1) {zeroSockAddress in
                SCNetworkReachabilityCreateWithAddress(nil, zeroSockAddress)
            }
        }
        
        var flags: SCNetworkReachabilityFlags = SCNetworkReachabilityFlags(rawValue: 0)
        if SCNetworkReachabilityGetFlags(defaultRouteReachability!, &flags) == false {
            return false
        }
        
        
        // Working for Cellular and WIFI
        let isReachable = (flags.rawValue & UInt32(kSCNetworkFlagsReachable)) != 0
        let needsConnection = (flags.rawValue & UInt32(kSCNetworkFlagsConnectionRequired)) != 0
        let ret = (isReachable && !needsConnection)
        
        return ret
        
    }
}

ViewController.swift

//
//  ViewController.swift
//  
//
//  Created by NETBIZ on 17/09/18.
//  Copyright © 2018 Netbiz.in. All rights reserved.
//
import UIKit

class ViewController: UIViewController {
  
  override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        //Check for connectivity
        if Reachability.isConnectedToNetwork() == true {
          // code to execute if internet is available
        } else {
            let alert = UIAlertController(title: "Connection Issue", message: "Please check your internet connection, you seem to be offline. Offline weather data of a previous location will be shown until you are online again. ", preferredStyle: .alert)
            let ok = UIAlertAction(title: "Ok", style: .default, handler: nil)
            alert.addAction(ok)
            present(alert, animated: true, completion: nil)
        }
     
    }
  
      override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}