Does AFNetworking have backgrounding support?

Question

I'm in the process of investigating AFNetworking as a replacement for ASIHTTPRequest, and notice a complete lack of information on whether it supports background downloads/uploads.

With an ASIHTTPReqeust object, all you have to do is call [request setShouldContinueWhenAppEntersBackground:YES] and the request will continue in the background. Is there any support for this in AFNetworking?

If there isn't (I'm not sure whether there *is* support for background execution in `AFNetworking`), you could always port across whatever extra features you want from `AFNetworking` into `ASIHTTPRequest`, or add background execution support (relatively simple) to `AFNetworking`. — , Oct 17 '11 at 23:09

score 48 · Accepted Answer · edited Jan 25 '13 at 11:42

48

EDIT: As of AFNetworking 1.0RC1, this is an explicit feature. AFURLConnectionOperation now has the method setShouldExecuteAsBackgroundTaskWithExpirationHandler:, which transparently manages all of this for you.

It's an implicit feature, so I didn't really think about advertising it. All you'd need to do is:


- (void)applicationWillResignActive:(UIApplication *)application {
    __block UIBackgroundTaskIdentifier backgroundTaskIdentifier = [application beginBackgroundTaskWithExpirationHandler:^(void) {
        [application endBackgroundTask:backgroundTaskIdentifier];
        [[YourRestClient sharedClient] cancelAllHTTPOperations];
    }];
}

Or, if you manage your operations in your own NSOperationQueue, just -cancelAllOperations here instead.

edited Jan 25 '13 at 11:42

Luke Mcneice

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answered Oct 24 '11 at 20:53

mattt

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Mattt - sounds like you're giving a solution for canceling networking when moving into the background though the question was about spawning/continuing AFNetworking ops when moving into the background. Thoughts on that? Given that most AF methods are block based / return immediately, I've found that the system believes they are complete before they really run their course... Maybe just using waitUntilFinished when running in a background mode? – Hunter Nov 07 '11 at 01:13
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@Hunter I think, you understand it wrong. Calling beginBackgroundTaskWithExpirationHandler ensures that requests continue in the background. The requests will not be canceled until the app is inactive for a longer time (like 10 min). – Felix Nov 18 '11 at 13:45
Yeah, you're completely right. I don't know what I was thinking when I wrote the above. – Hunter Nov 19 '11 at 16:55
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WARNING: do not use mattt's beginBackgroundTaskWithExpirationHandler code on applicationWillResignActive WITHOUT ADDING a matching call to endBackgroundTask - otherwise IOS will kill your app after 600 seconds, and foregrounding will relaunch your app. – mr_marc Jan 25 '12 at 00:04
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`- (void)applicationWillResignActive:(UIApplication *)application { UIBackgroundTaskIdentifier backgroundIdentifier = [application beginBackgroundTaskWithExpirationHandler:^(void) { [[AFHTTPClient sharedClient] cancelAllHTTPOperations]; }]; [application endBackgroundTask:backgroundIdentifier]; }` – mr_marc Jan 25 '12 at 00:06
@mattt, I'm only now looking into AFNetworking, but it seems from your example that you can only do backgrounding on a global level, in contrast to ASIHTTPRequest's ability to specify which requests to background. Is this correct? – poetmountain Mar 09 '12 at 22:12
@BourbonJockey This will [likely be added to the next release](https://github.com/AFNetworking/AFNetworking/pull/259) (1.0) – mattt Mar 20 '12 at 18:44
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@mattt you might want to update your answer to mention the `setShouldExecuteAsBackgroundTaskWithExpirationHandler:` you've added. I didn't realize it was there in the version I downloaded a couple of weeks ago. – brainjam May 18 '12 at 20:54
You should add `__block` modifier to `UIBackgroundTaskIdentifier backgroundTaskIdentifier`, or the block will capture its initialized value. – Vadim Yelagin May 21 '12 at 05:21
@mattt I simply love AFNetworking but in a "legacy" project I'm using a `NSOperationQueue` object. I have a question for you and if you can reply I would be grateful. Within the `main` method of a `NSOperation` subclass, I download a from a service through `+sendSynchronousRequest:returningResponse:error`. Once dowloaded, the file is imported within core data. A cancel request can happen at any time. So, does the cancellation could be handled in the right way or do I need to use aync pattern to deal with cancellation request? Thanks for your support. – Lorenzo B Nov 14 '12 at 22:19
What is the `[[YourRestClient sharedClient] cancelAllHTTPOperations];` line referring to? – HighFlyingFantasy Mar 13 '13 at 01:11
cancelAllHTTPOperations seems not to be included any longer in the AFHTTPClient class. Instead use [[[YourHTTPClient sharedClient] operationQueue] cancelAllOperations]; – Diego Jun 10 '13 at 13:49

Does AFNetworking have backgrounding support?

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