Using Apple's Reachability to check remote server reachability in Swift

Question

I\'m developing an iOS application written in Swift that communicates with a HTTP server on the local network, and I\'m using Apple\'s Reachability class to determine wether

Answer 1

In swift,

About what I understood of reachability utility propose by Apple (https://developer.apple.com/library/ios/samplecode/Reachability/Introduction/Intro.html) or tonymillion (https://github.com/tonymillion/Reachability) which are basically the same is :

you have 3 possible test :

• local (can access local network but not internet)
• extern (can access internet by ip address)
• dns (can access internet and reach an hostname)

You can test them respectively by starting a notifier with this :

let wifiReachability = Reachability. reachabilityForLocalWiFi()
wifiReachability.startNotifier()

let internetReachability = Reachability.reachabilityForInternetConnection()
hostReachability.startNotifier()

let hostReachability = Reachability(hostName:"www.apple.com")
hostReachability.startNotifier()

Which will trigger a notification that you can catch with this method : NSNotificationCenter.defaultCenter().addObserver()

So to use them you can do something like that :

create a function in your appDelegate which will instantiate the notifier :

func startReachabilityTest()
{
    // Allocate a reachability object to test internet access by hostname
    let reach = Reachability(hostName: "www.apple.com")

    // Tell the reachability that we DON'T want to be reachable on 3G/EDGE/CDMA
    //reach.reachableOnWWAN = false

    reach.startNotifier()
}

Then you can call it in the didFinishLaunchingWithOptions of your appDelegate :

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    self.startReachabilityTest();
}

if want to catch the event in any viewController just add this line to viewDidLoad :

override func viewDidLoad()
{
    // Here we set up a NSNotification observer. The Reachability that caused the notification
    // is passed in the object parameter
    NSNotificationCenter.defaultCenter().addObserver(
            self,
            selector: "reachabilityChanged:",
            name: kReachabilityChangedNotification,
            object: nil)
}

and add this method method to react to the event :

func reachabilityChanged(notice: NSNotification)
{
    println("reachability changed")
    let reach = notice.object as? Reachability
    if let remoteHostStatus = reach?.currentReachabilityStatus()
    {
        if remoteHostStatus == NetworkStatus.NotReachable
        {
            println("not reachable")
        }
        else
        {
            println("reachable")
        }
    }
}

You can also catch the event inside your appDelegate by adding NSNotificationCenter.defaultCenter().addObserver() inside didFinishLaunchingWithOptions and then add reachabilityChanged(notice: NSNotification) in it.

Ah, also note that you can easily add reachability class to your project with cocoapods by adding this line :

pod 'Reachability', '~> 3.2'

To your pod file and them after a pod install in command line just add this line to xxx-Bridging-Header.h header file (where xxx is the name of your app) :

#import 

If you don't have bridging header in your project you can follow this tutorial : http://www.learnswiftonline.com/getting-started/adding-swift-bridging-header/

No need to add systemConfiguration.framework which is already added by pod dependencies.

Note : Reachability does not work fine in the simulator

hope this help!