check internet connection in cocoa application

Question

How do I check internet connection in an OS X cocoa application? Can Apple\'s iOS Reachability example code be reused for this purpose?

Thanks,

Nava

Answer 1

The current version of Reachability code (2.2) listed on Apple's site and referenced above does NOT compile as-is for a Mac OS X Cocoa application. The constant kSCNetworkReachabilityFlagsIsWWAN is only available when compiling for TARGET_OS_IPHONE and Reachability.m references that constant. You will need to #ifdef the two locations in Reachability.m that reference it like below:

#if TARGET_OS_IPHONE
      (flags & kSCNetworkReachabilityFlagsIsWWAN)               ? 'W' : '-',
#else
      0,
#endif

and

#if TARGET_OS_IPHONE
if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)
{
    // ... but WWAN connections are OK if the calling application
    //     is using the CFNetwork (CFSocketStream?) APIs.
    retVal = ReachableViaWWAN;
}
#endif

Answer 2

This code will help you to find if internet is reachable or not:

-(BOOL)isInternetAvail
{
    BOOL bRet = FALSE;
    const char *hostName = [@"google.com" cStringUsingEncoding:NSASCIIStringEncoding];
    SCNetworkConnectionFlags flags = 0;

    if (SCNetworkCheckReachabilityByName(hostName, &flags) && flags > 0) 
    {
        if (flags == kSCNetworkFlagsReachable)
        {
            bRet = TRUE;
        }
        else
        {
        }
    }
    else 
    {
    }
    return bRet;
}

For more information you can look at the iphone-reachability

Answer 3

Unicorn's solution is deprecated, but you can get equivalent results using the following code:

SCNetworkReachabilityRef target;

SCNetworkConnectionFlags flags = 0;

Boolean ok;

target = SCNetworkReachabilityCreateWithName(NULL, hostName);

ok = SCNetworkReachabilityGetFlags(target, &flags);

CFRelease(target);

Answer 4

Apple has a nice code which does it for you. You can check if your connection is WiFi for instnace or just cell/WiFi. link text

Answer 5

I know this is an old thread but for anyone running into this in 2018, there's an simpler and quicker solution using a Process and the ping command.

Swift 4 example:

func ping(_ host: String) -> Int32 {
    let process = Process.launchedProcess(launchPath: "/sbin/ping", arguments: ["-c1", host])
    process.waitUntilExit()
    return process.terminationStatus
}

let internetAvailable = ping("google.com") == 0
print("internetAvailable \(internetAvailable)")