Hi Rick, I thought I'd pass along a message from Quinn in Apple's DTS group on this topic. Also, fyi, <http://www.lists.apple.com/macnetworkprog> is better for networking questions
-Ken Doing your NSConnection stuff synchronously is a mistake, even if > NSBlockOperation makes it easier. There are three major issues: > o resource usage -- Threads are expensive, so having a bunch of threads > sitting around literally doing nothing is not a great idea. This is major > concern on iOS, much less so on Mac OS X. > o cancellation -- It's hard to implement cancellation in this sort of > setup. > o no delegate -- +[NSURLConnection sendSynchronousRequest:...] does not > provide you with a delegate, which means you can't handle authentication > challenges. This is a problem because, even if the HTTP resource itself is > not protected, you might be behind an authenticating proxy. On iOS there's > no avoiding this; you have to handle authentication challenges. On Mac OS X > this is only a problem if the existing proxy credentials (in the keychain) > are wrong. > You can resolve all of these issues, and stay within the NSOperation > universe, by using a concurrent operation that manages an async > NSURLConnection. The QHTTPOperation class is a good example of this. > <http://developer.apple.com/library/mac/#samplecode/LinkedImageFetcher/> <http://developer.apple.com/library/ios/#samplecode/MVCNetworking/> On Thu, Jan 20, 2011 at 2:51 PM, Rick Mann <rm...@latencyzero.com> wrote: > With the advent of code blocks and NSBlockOperation, it's a lot tidier, and > easier, to write code using NSURLConnection, particularly in the presence of > multiple operations. The approach is to use an NSBlockOperation and > +[NSURLConnection > sendSynchronousRequest:returningResponse:error:] to synchronously request a > resource (which occurs on a separate thread). > > The alternative is to use the asynchronous methods, and then manage all the > state necessary to keep track of multiple instances of the same request. I > prefer the former approach, but does Apple still recommend the async > approach? Or is there no real difference between the two? > > I'm running on iOS 4.x, on a single-core device, but I don't think these > devices will remain single-core for long, and the same question applies to > multicore Macs. > > Thanks, > Rick > > _______________________________________________ > > 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/kenferry%40gmail.com > > This email sent to kenfe...@gmail.com > _______________________________________________ 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
