On Sun, Oct 16, 2011 at 2:45 PM, John Love <jote...@charter.net> wrote: > I really have been just about everywhere, e.g., stack overflow.com and > iphonedevsdk.com and have really learned a lot … unfortunately, what I have > learned is that there are opposing opinions on how to best check for an > active internet connection with respect to effectiveness and speed. Such > comments such as "You're not testing for what you think you are!".
The only way to test if you can connect to a host is to actually try to connect to the host. Reachability can only tell you if the device is aware that it has no route to that host. It's a good way to fail quickly (for example, if the device knows all of its interfaces are down), but the only authoritative answer can be gained by actually attempting to connect. > > Considering my lack of success with Apple's Reachability Code, I have found > that the asynchronous call to: > > NSString *urlString = @"myURL"; > NSURL *theURL = [NSURL URLWithString:urlString]; > NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:theURL]; > NSURLConnection *theConnection = [NSURLConnection > connectionWithRequest:theRequest delegate:self]; > > which does hook up with the delegate method: > - (void )connection:(NSURLConnection *)connection didFailWithError:(NSError > *)error > > This magic does indeed work, but I could fry a couple of eggs while I'm > waiting and I know that the iApp folks will bounce me for that delay. If you want a shorter timeout, call -setTimeoutInterval: on your NSMutableURLRequest. > > Maybe my method of "taking my connection" down may be in error -- I am simply > pushing off the "standby" button on my cable modem -- I have also just > unplugged the modem. No, that's a good test. It simulates an upstream problem. You could also run in the Simulator and turn on the new Network Link Conditioner in Lion (/Applications/Utilities/Network Link Conditioner) if you want to simulate a poor 3G or EDGE connection. > Isn't the function of -startNotifier to enable the callback method to be > continuously called within the main RunLoop? As the name of the notification indicates, the system only sends that notification when the reachability has changed. It doesn't periodically send out notifications. If you have previously refused to attempt a connection because reachability said you had no route to the host, you should try again when you receive the "reachability changed" notification. You might early out again (host still not reachable), or you might attempt to connect and either succeed or fail. > > Yet the only time I can get this callback method to be called is if I call > NSNotificationCenter's -postNotificationName elsewhere in the code?? > > -[notificationCenter postNotificationName:kReachabilityChangedNotification > object:internetReachability_]; The system posts this notification. You should never post it yourself. Hope that helps, --Kyle Sluder _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
