speed - ios check internet connection without reachability




How to check for an active Internet connection on iOS or macOS? (20)

  1. Download the Reachability file, https://gist.github.com/darkseed/1182373

  2. And add CFNetwork.framework and 'SystemConfiguration.framework' in framework

  3. Do #import "Reachability.h"


First: Add CFNetwork.framework in framework

Code: ViewController.m

- (void)viewWillAppear:(BOOL)animated
{
    Reachability *r = [Reachability reachabilityWithHostName:@"www.google.com"];
    NetworkStatus internetStatus = [r currentReachabilityStatus];

    if ((internetStatus != ReachableViaWiFi) && (internetStatus != ReachableViaWWAN))
    {
        /// Create an alert if connection doesn't work
        UIAlertView *myAlert = [[UIAlertView alloc]initWithTitle:@"No Internet Connection"   message:NSLocalizedString(@"InternetMessage", nil)delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
        [myAlert show];
        [myAlert release];
    }
    else
    {
         NSLog(@"INTERNET IS CONNECT");
    }
}

I would like to check to see if I have an Internet connection on iOS using the Cocoa Touch libraries or on macOS using the Cocoa libraries.

I came up with a way to do this using an NSURL. The way I did it seems a bit unreliable (because even Google could one day be down and relying on a third party seems bad), and while I could check to see for a response from some other websites if Google didn't respond, it does seem wasteful and an unnecessary overhead on my application.

- (BOOL) connectedToInternet
{
    NSString *URLString = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com"]];
    return ( URLString != NULL ) ? YES : NO;
}

Is what I have done bad, (not to mention stringWithContentsOfURL is deprecated in iOS 3.0 and macOS 10.4) and if so, what is a better way to accomplish this?


Very simple.... Try these steps:

Step 1: Add the SystemConfiguration framework into your project.


Step 2: Import the following code into your header file.

#import <SystemConfiguration/SystemConfiguration.h>

Step 3: Use the following method

  • Type 1:

    - (BOOL) currentNetworkStatus {
        [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
        BOOL connected;
        BOOL isConnected;
        const char *host = "www.apple.com";
        SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithName(NULL, host);
        SCNetworkReachabilityFlags flags;
        connected = SCNetworkReachabilityGetFlags(reachability, &flags);
        isConnected = NO;
        isConnected = connected && (flags & kSCNetworkFlagsReachable) && !(flags & kSCNetworkFlagsConnectionRequired);
        CFRelease(reachability);
        return isConnected;
    }
    

  • Type 2:

    Import header : #import "Reachability.h"

    - (BOOL)currentNetworkStatus
    {
        Reachability *reachability = [Reachability reachabilityForInternetConnection];
        NetworkStatus networkStatus = [reachability currentReachabilityStatus];
        return networkStatus != NotReachable;
    }
    

Step 4: How to use:

- (void)CheckInternet
{
    BOOL network = [self currentNetworkStatus];
    if (network)
    {
        NSLog(@"Network Available");
    }
    else
    {
        NSLog(@"No Network Available");
    }
}

First: Add CFNetwork.framework in framework

Code: ViewController.m

#import "Reachability.h"

- (void)viewWillAppear:(BOOL)animated
{
    Reachability *r = [Reachability reachabilityWithHostName:@"www.google.com"];
    NetworkStatus internetStatus = [r currentReachabilityStatus];

    if ((internetStatus != ReachableViaWiFi) && (internetStatus != ReachableViaWWAN))
    {
        /// Create an alert if connection doesn't work
        UIAlertView *myAlert = [[UIAlertView alloc]initWithTitle:@"No Internet Connection"   message:NSLocalizedString(@"InternetMessage", nil)delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
        [myAlert show];
        [myAlert release];
    }
    else
    {
         NSLog(@"INTERNET IS CONNECT");
    }
}

Important: This check should always be performed asynchronously. The majority of answers below are synchronous so be careful otherwise you'll freeze up your app.


Swift

1) Install via CocoaPods or Carthage: https://github.com/ashleymills/Reachability.swift

2) Test reachability via closures

let reachability = Reachability()!

reachability.whenReachable = { reachability in
    if reachability.connection == .wifi {
        print("Reachable via WiFi")
    } else {
        print("Reachable via Cellular")
    }
}

reachability.whenUnreachable = { _ in
    print("Not reachable")
}

do {
    try reachability.startNotifier()
} catch {
    print("Unable to start notifier")
}

Objective-C

1) Add SystemConfiguration framework to the project but don't worry about including it anywhere

2) Add Tony Million's version of Reachability.h and Reachability.m to the project (found here: https://github.com/tonymillion/Reachability)

3) Update the interface section

#import "Reachability.h"

// Add this to the interface in the .m file of your view controller
@interface MyViewController ()
{
    Reachability *internetReachableFoo;
}
@end

4) Then implement this method in the .m file of your view controller which you can call

// Checks if we have an internet connection or not
- (void)testInternetConnection
{   
    internetReachableFoo = [Reachability reachabilityWithHostname:@"www.google.com"];

    // Internet is reachable
    internetReachableFoo.reachableBlock = ^(Reachability*reach)
    {
        // Update the UI on the main thread
        dispatch_async(dispatch_get_main_queue(), ^{
            NSLog(@"Yayyy, we have the interwebs!");
        });
    };

    // Internet is not reachable
    internetReachableFoo.unreachableBlock = ^(Reachability*reach)
    {
        // Update the UI on the main thread
        dispatch_async(dispatch_get_main_queue(), ^{
            NSLog(@"Someone broke the internet :(");
        });
    };

    [internetReachableFoo startNotifier];
}

Important Note: The Reachability class is one of the most used classes in projects so you might run into naming conflicts with other projects. If this happens, you'll have to rename one of the pairs of Reachability.h and Reachability.m files to something else to resolve the issue.

Note: The domain you use doesn't matter. It's just testing for a gateway to any domain.



Apple provides a sample app which does exactly this:

Reachability


First download the reachability class and put reachability.h and reachabilty.m file in your Xcode.

The best way is to make a common Functions class (NSObject) so that you can use it any class. These are two methods for a network connection reachability check:

+(BOOL) reachabiltyCheck
{
    NSLog(@"reachabiltyCheck");
    BOOL status =YES;
    [[NSNotificationCenter defaultCenter] addObserver:self
                                          selector:@selector(reachabilityChanged:)
                                          name:kReachabilityChangedNotification
                                          object:nil];
    Reachability * reach = [Reachability reachabilityForInternetConnection];
    NSLog(@"status : %d",[reach currentReachabilityStatus]);
    if([reach currentReachabilityStatus]==0)
    {
        status = NO;
        NSLog(@"network not connected");
    }
    reach.reachableBlock = ^(Reachability * reachability)
    {
        dispatch_async(dispatch_get_main_queue(), ^{
        });
    };
    reach.unreachableBlock = ^(Reachability * reachability)
    {
        dispatch_async(dispatch_get_main_queue(), ^{
        });
    };
    [reach startNotifier];
    return status;
}

+(BOOL)reachabilityChanged:(NSNotification*)note
{
    BOOL status =YES;
    NSLog(@"reachabilityChanged");
    Reachability * reach = [note object];
    NetworkStatus netStatus = [reach currentReachabilityStatus];
    switch (netStatus)
    {
        case NotReachable:
            {
                status = NO;
                NSLog(@"Not Reachable");
            }
            break;

        default:
            {
                if (!isSyncingReportPulseFlag)
                {
                    status = YES;
                    isSyncingReportPulseFlag = TRUE;
                    [DatabaseHandler checkForFailedReportStatusAndReSync];
                }
            }
            break;
    }
    return status;
}

+ (BOOL) connectedToNetwork
{
    // Create zero addy
    struct sockaddr_in zeroAddress;
    bzero(&zeroAddress, sizeof(zeroAddress));
    zeroAddress.sin_len = sizeof(zeroAddress);
    zeroAddress.sin_family = AF_INET;

    // Recover reachability flags
    SCNetworkReachabilityRef defaultRouteReachability = SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr *)&zeroAddress);
    SCNetworkReachabilityFlags flags;
    BOOL didRetrieveFlags = SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags);
    CFRelease(defaultRouteReachability);
    if (!didRetrieveFlags)
    {
        NSLog(@"Error. Could not recover network reachability flags");
        return NO;
    }
    BOOL isReachable = flags & kSCNetworkFlagsReachable;
    BOOL needsConnection = flags & kSCNetworkFlagsConnectionRequired;
    BOOL nonWiFi = flags & kSCNetworkReachabilityFlagsTransientConnection;
    NSURL *testURL = [NSURL URLWithString:@"http://www.apple.com/"];
    NSURLRequest *testRequest = [NSURLRequest requestWithURL:testURL  cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:20.0];
    NSURLConnection *testConnection = [[NSURLConnection alloc] initWithRequest:testRequest delegate:self];
    return ((isReachable && !needsConnection) || nonWiFi) ? (testConnection ? YES : NO) : NO;
}

Now you can check network connection in any class by calling this class method.


Here is how I do it in my apps: While a 200 status response code doesn't guarantee anything, it is stable enough for me. This doesn't require as much loading as the NSData answers posted here, as mine just checks the HEAD response.

Swift Code

func checkInternet(flag:Bool, completionHandler:(internet:Bool) -> Void)
{
    UIApplication.sharedApplication().networkActivityIndicatorVisible = true

    let url = NSURL(string: "http://www.appleiphonecell.com/")
    let request = NSMutableURLRequest(URL: url!)

    request.HTTPMethod = "HEAD"
    request.cachePolicy = NSURLRequestCachePolicy.ReloadIgnoringLocalAndRemoteCacheData
    request.timeoutInterval = 10.0

    NSURLConnection.sendAsynchronousRequest(request, queue:NSOperationQueue.mainQueue(), completionHandler:
    {(response: NSURLResponse!, data: NSData!, error: NSError!) -> Void in

        UIApplication.sharedApplication().networkActivityIndicatorVisible = false

        let rsp = response as! NSHTTPURLResponse?

        completionHandler(internet:rsp?.statusCode == 200)
    })
}

func yourMethod()
{
    self.checkInternet(false, completionHandler:
    {(internet:Bool) -> Void in

        if (internet)
        {
            // "Internet" aka Apple's region universal URL reachable
        }
        else
        {
            // No "Internet" aka Apple's region universal URL un-reachable
        }
    })
}

Objective-C Code

typedef void(^connection)(BOOL);

- (void)checkInternet:(connection)block
{
    NSURL *url = [NSURL URLWithString:@"http://www.appleiphonecell.com/"];
    NSMutableURLRequest *headRequest = [NSMutableURLRequest requestWithURL:url];
    headRequest.HTTPMethod = @"HEAD";

    NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration ephemeralSessionConfiguration];
    defaultConfigObject.timeoutIntervalForResource = 10.0;
    defaultConfigObject.requestCachePolicy = NSURLRequestReloadIgnoringLocalAndRemoteCacheData;

    NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration:defaultConfigObject delegate:self delegateQueue: [NSOperationQueue mainQueue]];

    NSURLSessionDataTask *dataTask = [defaultSession dataTaskWithRequest:headRequest
        completionHandler:^(NSData *data, NSURLResponse *response, NSError *error)
    {
        if (!error && response)
        {
            block([(NSHTTPURLResponse *)response statusCode] == 200);
        }
    }];
    [dataTask resume];
}

- (void)yourMethod
{
    [self checkInternet:^(BOOL internet)
    {
         if (internet)
         {
             // "Internet" aka Apple's region universal URL reachable
         }
         else
         {
             // No "Internet" aka Apple's region universal URL un-reachable
         }
    }];
}


I like to keep things simple. The way I do this is:

//Class.h
#import "Reachability.h"
#import <SystemConfiguration/SystemConfiguration.h>

- (BOOL)connected;

//Class.m
- (BOOL)connected
{
    Reachability *reachability = [Reachability reachabilityForInternetConnection];
    NetworkStatus networkStatus = [reachability currentReachabilityStatus];
    return networkStatus != NotReachable;
}

Then, I use this whenever I want to see if I have a connection:

if (![self connected]) {
    // Not connected
} else {
    // Connected. Do some Internet stuff
}

This method doesn't wait for changed network statuses in order to do stuff. It just tests the status when you ask it to.


I've used the code in this discussion, and it seems to work fine (read the whole thread!).

I haven't tested it exhaustively with every conceivable kind of connection (like ad hoc Wi-Fi).


If you're using AFNetworking you can use its own implementation for internet reachability status.

The best way to use AFNetworking is to subclass the AFHTTPClient class and use this class to do your network connections.

One of the advantages of using this approach is that you can use blocks to set the desired behavior when the reachability status changes. Supposing that I've created a singleton subclass of AFHTTPClient (as said on the "Subclassing notes" on AFNetworking docs) named BKHTTPClient, I'd do something like:

BKHTTPClient *httpClient = [BKHTTPClient sharedClient];
[httpClient setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status)
{
    if (status == AFNetworkReachabilityStatusNotReachable) 
    {
    // Not reachable
    }
    else
    {
        // Reachable
    }
}];

You could also check for Wi-Fi or WLAN connections specifically using the AFNetworkReachabilityStatusReachableViaWWAN and AFNetworkReachabilityStatusReachableViaWiFi enums (more here).


Only the Reachability class has been updated. You can now use:

Reachability* reachability = [Reachability reachabilityWithHostName:@"www.apple.com"];
NetworkStatus remoteHostStatus = [reachability currentReachabilityStatus];

if (remoteHostStatus == NotReachable) { NSLog(@"not reachable");}
else if (remoteHostStatus == ReachableViaWWAN) { NSLog(@"reachable via wwan");}
else if (remoteHostStatus == ReachableViaWiFi) { NSLog(@"reachable via wifi");}

The Reachability class is OK to find out if the Internet connection is available to a device or not...

But in case of accessing an intranet resource:

Pinging the intranet server with the reachability class always returns true.

So a quick solution in this scenario would be to create a web method called pingme along with other webmethods on the service. The pingme should return something.

So I wrote the following method on common functions

-(BOOL)PingServiceServer
{
    NSURL *url=[NSURL URLWithString:@"http://www.serveraddress/service.asmx/Ping"];

    NSMutableURLRequest *urlReq=[NSMutableURLRequest requestWithURL:url];

    [urlReq setTimeoutInterval:10];

    NSURLResponse *response;

    NSError *error = nil;

    NSData *receivedData = [NSURLConnection sendSynchronousRequest:urlReq
                                                 returningResponse:&response
                                                             error:&error];
    NSLog(@"receivedData:%@",receivedData);

    if (receivedData !=nil)
    {
        return YES;
    }
    else
    {
        NSLog(@"Data is null");
        return NO;
    }
}

The above method was so useful for me, so whenever I try to send some data to the server I always check the reachability of my intranet resource using this low timeout URLRequest.


There's a nice-looking, ARC- and GCD-using modernization of Reachability here:

Reachability


This used to be the correct answer, but it is now outdated as you should subscribe to notifications for reachability instead. This method checks synchronously:


You can use Apple's Reachability class. It will also allow you to check if Wi-Fi is enabled:

Reachability* reachability = [Reachability sharedReachability];
[reachability setHostName:@"www.example.com"];    // Set your host name here
NetworkStatus remoteHostStatus = [reachability remoteHostStatus];

if (remoteHostStatus == NotReachable) { }
else if (remoteHostStatus == ReachableViaWiFiNetwork) { }
else if (remoteHostStatus == ReachableViaCarrierDataNetwork) { }

The Reachability class is not shipped with the SDK, but rather a part of this Apple sample application. Just download it, and copy Reachability.h/m to your project. Also, you have to add the SystemConfiguration framework to your project.



Using Apple's Reachability code, I created a function that'll check this correctly without you having to include any classes.

Include the SystemConfiguration.framework in your project.

Make some imports:

#import <sys/socket.h>
#import <netinet/in.h>
#import <SystemConfiguration/SystemConfiguration.h>

Now just call this function:

/*
Connectivity testing code pulled from Apple's Reachability Example: https://developer.apple.com/library/content/samplecode/Reachability
 */
+(BOOL)hasConnectivity {
    struct sockaddr_in zeroAddress;
    bzero(&zeroAddress, sizeof(zeroAddress));
    zeroAddress.sin_len = sizeof(zeroAddress);
    zeroAddress.sin_family = AF_INET;

    SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr*)&zeroAddress);
    if (reachability != NULL) {
        //NetworkStatus retVal = NotReachable;
        SCNetworkReachabilityFlags flags;
        if (SCNetworkReachabilityGetFlags(reachability, &flags)) {
            if ((flags & kSCNetworkReachabilityFlagsReachable) == 0)
            {
                // If target host is not reachable
                return NO;
            }

            if ((flags & kSCNetworkReachabilityFlagsConnectionRequired) == 0)
            {
                // If target host is reachable and no connection is required
                //  then we'll assume (for now) that your on Wi-Fi
                return YES;
            }


            if ((((flags & kSCNetworkReachabilityFlagsConnectionOnDemand ) != 0) ||
                 (flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) != 0))
            {
                // ... and the connection is on-demand (or on-traffic) if the
                //     calling application is using the CFSocketStream or higher APIs.

                if ((flags & kSCNetworkReachabilityFlagsInterventionRequired) == 0)
                {
                    // ... and no [user] intervention is needed
                    return YES;
                }
            }

            if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)
            {
                // ... but WWAN connections are OK if the calling application
                //     is using the CFNetwork (CFSocketStream?) APIs.
                return YES;
            }
        }
    }

    return NO;
}

And it's iOS 5 tested for you.


- (void)viewWillAppear:(BOOL)animated
{
    NSString *URL = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com"]];

    return (URL != NULL ) ? YES : NO;
}

Or use the Reachability class.

There are two ways to check Internet availability using the iPhone SDK:

1. Check the Google page is opened or not.

2. Reachability Class

For more information, please refer to Reachability (Apple Developer).


-(void)newtworkType {

 NSArray *subviews = [[[[UIApplication sharedApplication] valueForKey:@"statusBar"] valueForKey:@"foregroundView"]subviews];
NSNumber *dataNetworkItemView = nil;

for (id subview in subviews) {
    if([subview isKindOfClass:[NSClassFromString(@"UIStatusBarDataNetworkItemView") class]]) {
        dataNetworkItemView = subview;
        break;
    }
}


switch ([[dataNetworkItemView valueForKey:@"dataNetworkType"]integerValue]) {
    case 0:
        NSLog(@"No wifi or cellular");
        break;

    case 1:
        NSLog(@"2G");
        break;

    case 2:
        NSLog(@"3G");
        break;

    case 3:
        NSLog(@"4G");
        break;

    case 4:
        NSLog(@"LTE");
        break;

    case 5:
        NSLog(@"Wifi");
        break;


    default:
        break;
}
}




reachability