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Lets say I have something like this:

AFJSONRequestOperation *operation = ...

[operation start];

When operation start is called, where is that operation placed ? In which queue? Is there any global (for class) operation queue where this operation is placed and I can access this operation ?

Because I would need to call (in some cases) [operation stop] (maybe not called like that, but just to remove operation from queue, and to stop it) from another method, is there a way to do it ?

Or should I use instance variable AFJSONRequestOperation and then access it like that? Although I have many different operations and that would make me create many instance variables so if there is some other way.

Thank you.

zhuber
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1 Answers1

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I'm not particularly familiar with AFNetworking, but as far as I know AFJSONRequestOperation uses NSURLConnection internally.

If you simply call start on the operation yourself it will execute the request on a background thread supplied by NSURLConnection. It will not therefore be in any queue. You should keep a reference to the operation yourself to stop it being deallocated, and use some kind of callback or block to handle the results, perhaps something provided by AFJSONRequestOperation, or via Key Value Observing the isFinished property of the NSOperation.

Alternatively, because AFJSONRequestOperation is an NSOperation you can add this to an NSOperationQueue that you have created or perhaps one provided by some other framework feature. In that case the NSOperationQueue will call the start method for you, and manage the objects lifetime as it is being processed. Again you will have to determine the best way to handle the results when the operation finishes.

Rory O'Bryan
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  • Thanks. Did it with NSOperationQueue instance variable from which i controlled all operations. – zhuber May 26 '13 at 13:37
  • Calling -start will execute the request on the calling thread. AFNetworking uses its own dedicated networking thread, so most of the work is being done in the background. You may want to consider using `AFHTTPClient`, which manages its own operation queue, as well as providing other useful functionality for communicating with a web service. – mattt May 26 '13 at 17:39
  • I think it's safe to say that @mattt is familiar with AFNetworking!!! So it sounds like you'd be well served by looking into `AFHTTPClient` as well. As @mattt correctly points out, I was somewhat imprecise in my answer with regards to the threads involved when you call `start`. The aspect I was trying to highlight was that whereas you might use an `NSOperationQueue` to get background threading / queuing, NSURLConnection comes with it built in, so doesn't need an NSOperationQueue to run. I was extrapolating out from there into AFNetworking, which I'll stop doing now :-). – Rory O'Bryan May 26 '13 at 21:20