Tutorial: Check for Internet Connection in Swift

There are many reasons you need to check if the user is connected to the internet within your app, most important is that your app needs to retrieve data from a feed or display a web view. As soon as your app is loaded and before you make any calls to get data from a feed you should check if the user is connected to the internet.

In the past in Objective-C the most common way to check for connectivity is using Reachability, but it hasn’t been converted to Swift as of yet. Below is a simple way to add this feature to your new Swift project.

1. Create a new Swift file within your project, name it “Reachability.swift”.
2. Cut & paste the following code into it to create your class.

   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(sizeofValue(zeroAddress))
           zeroAddress.sin_family = sa_family_t(AF_INET)
           
           let defaultRouteReachability = withUnsafePointer(&zeroAddress) {
               SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, UnsafePointer($0))
           }
           
           var flags: SCNetworkReachabilityFlags = SCNetworkReachabilityFlags(rawValue: 0)
           if SCNetworkReachabilityGetFlags(defaultRouteReachability!, &flags) == false {
               return false
           }
           
           let isReachable = flags == .Reachable
           let needsConnection = flags == .ConnectionRequired
           
           return isReachable && !needsConnection
           
       }
   }
   

3. You can check internet connection anywhere in your project using this code:

   if Reachability.isConnectedToNetwork() == true {
       println("Internet connection OK")
   } else {
       println("Internet connection FAILED")
   }
   

4. If the user is not connected to the internet, you may want to show them an alert dialog to notify them.

   if Reachability.isConnectedToNetwork() == true {
       println("Internet connection OK")
   } else {
       println("Internet connection FAILED")
       var alert = UIAlertView(title: "No Internet Connection", message: "Make sure your device is connected to the internet.", delegate: nil, cancelButtonTitle: "OK")
       alert.show()
   }
   

   You can grab the full source code for this tutorial. Note: Built for Xcode 7.1.