Check for internet connection with Swift

Question

When I try to check for an internet connection on my iPhone I get a bunch of errors. Can anyone help me to fix this?

The code:

import Foundation
impo         


        

Answer 1

struct Connectivity {
        static let sharedInstance = NetworkReachabilityManager()!
        static var isConnectedToInternet:Bool {
            return self.sharedInstance.isReachable
        }
    }

Now call it

if Connectivity.isConnectedToInternet{
            call_your_methods_here()
        }else{
            show_alert_for_noInternet()
        }

Answer 2

While it may not directly determine whether the phone is connected to a network, the simplest(, cleanest?) solution would be to 'ping' Google, or some other server, (which isn't possible unless the phone is connected to a network):

private var urlSession:URLSession = {
    var newConfiguration:URLSessionConfiguration = .default
    newConfiguration.waitsForConnectivity = false
    newConfiguration.allowsCellularAccess = true
    return URLSession(configuration: newConfiguration)
}()

public func canReachGoogle() -> Bool
{
    let url = URL(string: "https://8.8.8.8")
    let semaphore = DispatchSemaphore(value: 0)
    var success = false
    let task = urlSession.dataTask(with: url!)
    { data, response, error in
        if error != nil
        {
            success = false
        }
        else
        {
            success = true
        }
        semaphore.signal()
    }

    task.resume()
    semaphore.wait()

    return success
}

If you're concerned that the server may be down or may block your IP, you can always ping multiple servers in a similar fashion and return whether any of them are reachable. Or have someone set up a dedicated server just for this purpose.

Answer 3

Although it does not directly answers your question, I would like to mention Apple recentely had this talk:

https://developer.apple.com/videos/play/wwdc2018/714/

At around 09:55 he talks about doing this stuff you are asking about:

1. Check connection
2. If connection -> Do something
3. If no connection -> Do something else (wait? retry?)

However, this has a few pitfalls:

• What if in step 2 it says it has a connection, but 0.5 seconds later he hasn't?
• What if the user is behind a proxy
• Last but not least, what if some answers here can not determine the connectivity right? (I am sure that if you rapidly switch your connection, go to wi-fi and turn it off (just make it complicated), it almost never can correctly determine whetever I got a connection or not).
• Quote from the video: "There is no way to guarentee whether a future operation will succeed or not"

The following points are some best practices according to Apple:

• set waitsForConnectivity to true (https://developer.apple.com/documentation/foundation/urlsessionconfiguration/2908812-waitsforconnectivity)
• respond to the delegate method taskIsWaitingForConnectivity (https://developer.apple.com/documentation/foundation/urlsessiontaskdelegate/2908819-urlsession). This is Apple's recommended way to check for connectivity, as mentioned in the video at 33:25.

According to the talk, there shouldn't be any reason to pre-check whetever you got internet connection or not, since it may not be accurate at the time you send your request to the server.