> On Dec 8, 2015, at 01:11 , Quinn The Eskimo! <eski...@apple.com> wrote: > > > On 8 Dec 2015, at 01:58, Rick Mann <rm...@latencyzero.com> wrote: > >> Also, I presume this only works if the queue is a serial queue, but the docs >> say it doesn't have to be such. > > You really want your NSURLSession delegate queue to be a serial queue. It's > going to be very hard to maintain coherent state otherwise. Moreover, your > delegate queue work should be fast, so serialisation isn't a problem. If you > need to do real work in this context, that work itself should be farmed off > to a separate thread/queue/NSOperation.
Yes, it has always been a serial queue. Rather, it's the default queue created by NSURLSession (which the docs say is serial). I pass nil in this parameter. Also, I use callback blocks, not delegates. > > On 8 Dec 2015, at 03:52, Rick Mann <rm...@latencyzero.com> wrote: > >> And, the answer is no. My completion block gets called MANY more times after >> I invalidate and cancel the session. > > I'm confused by this. Are you looking to invalidate the session or not? If > you don't mind invalidating the session (-invalidateAndCancel), you should be > able to kick off the new work your -URLSession:didBecomeInvalidWithError: > delegate callback, which is the last callback you'll get for this session and > which will arrive after all your task cancellation callbacks have run. Here's what I do: 0) Request a list of signed S3 URLs from our endpoint 1) loop through the list of URLs I have to download (300 or so), and create download tasks on a single shared session, with a callback function. 2) Set a breakpoint after a few of these have completed 3) Wait 5 minutes for the signatures to expire 4) Resume running 5) Next callback is 403, call invalidateAndCancel 6) Additional callbacks get called, with more 403 results. I can't re-start downloads in (5) without some additional state information. If I set a flag that says I've restarted downloads, so that the remaining 403 callbacks don't also restart downloads, then eventually I need to clear that flag, but there's no way to know that the last error has come through. The only way I can see to do this is to create additional state *per session* to keep track of what's going on, so I can invalidate the session for myself to short-circuit all the additional callbacks, and then create a new session with my additional state to restart the downloads. All because NSURLSession has no mechanism to determine if it's finished with everything. I can't even query NSURLSession to see if it's invalid (which is all the state I really need to short-circuit remaining callbacks). > Share and Enjoy > -- > Quinn "The Eskimo!" <http://www.apple.com/developer/> > Apple Developer Relations, Developer Technical Support, Core OS/Hardware > > > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Macnetworkprog mailing list (Macnetworkprog@lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/macnetworkprog/rmann%40latencyzero.com > > This email sent to rm...@latencyzero.com -- Rick Mann rm...@latencyzero.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Macnetworkprog mailing list (Macnetworkprog@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/macnetworkprog/archive%40mail-archive.com This email sent to arch...@mail-archive.com
