Swift iOS- What to do when there is a wifi connection but no internet connection?

Question

I'm using Alamofire in my iOS app. I use bool values in viewWillAppear and in AppDelegate with NSNotifications to check if there is an internet connection. If there is no wifi connection a pop up appears to inform the user. If there is a wifi connection the pop up disappears and everything works fine again. I've had no problems as long as wifi is clearly not working.

I was at a meetup and someone explained to me that the way it works is it it looks for a wifi connection and not an internet connection. For e.g.. if I have a wifi router and it's plugged in but the router isn't connected to the internet Alamofire will view this as a successful connection because it actually is connecting to wifi although it doesn't know the wifi can't connect to the internet.

I was just in a situation where I connected to an open network, my app initially responded as if I were actually connected to the internet (no pop up) but I couldn't get connect to anything. The wifi signal was on full. In terminal I ran a ping and it turns out the connection was dead. My app couldn't tell the difference.

How do I make a pop up appear in a sitaution like this?

Also what is .case unknown for?

Alamofire.Swift:

import Foundation
import Alamofire

open class NetworkManager {

    open static var sharedManager: NetworkReachabilityManager = {

        let reachabilityManager = NetworkReachabilityManager()

        reachabilityManager?.listener = { (status) in

            switch status {

            case .notReachable:
                print("The network is not reachable")
                NotificationCenter.default.post(name: NSNotification.Name(rawValue: "unsuccessful"), object: nil)

            case .unknown : //???????
                print("It is unknown wether the network is reachable")
                //I'm not sure whether to put a Notification for successful or unsuccessful???

            case .reachable(.ethernetOrWiFi):
                print("The network is reachable over the WiFi connection")
                NotificationCenter.default.post(name: NSNotification.Name(rawValue: "successful"), object: nil)

            case .reachable(.wwan):
                print("The network is reachable over the WWAN connection")
                NotificationCenter.default.post(name: NSNotification.Name(rawValue: "successful"), object: nil)
            }
        }

        reachabilityManager?.startListening()
        return reachabilityManager!
    }()
}

AppDelegate:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

        NetworkManager.sharedManager.startListening()

SomeVC:

override func viewWillAppear() {
        super.viewWillAppear()

        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(successful), name: "successful", object: nil)

        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(unsuccessful), name: "unsuccessful", object: nil)

       if NetworkManager.sharedManager.isReachable == true{
            self.successful()
       }else{
            self.unsuccessful()
       }

       if NetworkManager.sharedManager.isReachableOnWWAN == true{ 
            self.successful()
       }else{
            self.unsuccessful()
       }

       if NetworkManager.sharedManager.isReachableOnEthernetOrWiFi == true{ 
            self.successful()
       }else{
            self.unsuccessful()
       }
}

func successful(){
    //dismiss pop up
}

func unsuccessful(){
    //show pop up
}

deinit{
    NSNotificationCenter.defaultCenter().removeObserver(self, name: "successful", object: nil)
    NSNotificationCenter.defaultCenter().removeObserver(self, name: "unsuccessful", object: nil)
}
}

Answer 1

You can init NetworkReachabilityManagerwith host, for example, google host, because default is 0.0.0.0

let reachabilityManager = Alamofire.NetworkReachabilityManager(host: "www.google.com")

When you start listening reachability manager doing ping to host. If network is available you can cache SSID and ping again when SSID changed.

For case .unknown better put a Notification for unsuccessful.

Example get SSID (it doesn't work in Simulator):

func fetchSSIDInfo() ->  String? {  
        if let interfaces = CNCopySupportedInterfaces() {  
            for i in 0..<CFArrayGetCount(interfaces){  
                let interfaceName: UnsafeRawPointer = CFArrayGetValueAtIndex(interfaces, i)  
                let rec = unsafeBitCast(interfaceName, to: AnyObject.self)  
                let unsafeInterfaceData = CNCopyCurrentNetworkInfo("\(rec)" as CFString)  

                if let unsafeInterfaceData = unsafeInterfaceData as? Dictionary<AnyHashable, Any> {  
                    return unsafeInterfaceData["SSID"] as? String  
                }  
            }  
        }  
        return nil  
    }