NSURLSession has NSoperationqueue internally?

Question

A)If NSURLSession runs task in background in iOS7,Has Apple integrated internally Queue in NSURLSession?How it works in secondary thread and also in App suspended Mode?

B)What is the difference between NSURLSession and NSoperationqueue?

C)If NSURLSession is the replacement of NSURLCOnnection, Can we integrate NSURLSession into NSOPerationqueue?

D)Are both same?

E)Can we do the same thing in NSURLSession as in NSoperationQueue?

f)is there any time limit to do task in background after closing application? because iOS7 does 2 min while ios6 does 10 min?

G) Tutorial says under section Configuration and Limitation,NSURLSessionDataTasks are not supported in background sessions at all, and you should only use these tasks for short-lived, small requests, not for downloads or uploads.some tutorials are telling there is no time limit, we can download or upload data,the size may be whatever..Please explain more on this? If NSURLSession is the relplacement of NSUrlconnection ,Which one is the best in all situations?What is the future of NSUrlconnection?

Answer 1

A) Yes, NSURLSession has its operation queue which maintains all the session tasks delegates in queue.

B) No, NSURLSession and NSOperationQueue has nothing for comparison. In fact, NSURLSession itself has a property of NSOperationQueue. NSURLSession is a replacement-API for NSURLConnection not NSOperationQueue.

C) There is no need of explicitly integrating it to NSOperationQueue. Every NSURLSession object has its own NSOperationQueue to perform its tasks concurrently.

D) Refer A,B,C

E) Again, this is a wrong comparison, NSURLSession is not replacement or equivalent for NSOperationQueue, it is replacement for NSURLConnection.

F) NSURLSession enables to use iOS7 background fetch mode with a background session configuration

[NSURLSessionConfiguration backgroundSessionConfiguration:@"identifier"];

If your question is about general background task execution, in iOS7 you can perform a task in background for 180.0 seconds. But for the background fetch request, you can fetch only for 30.0 seconds

G) Yes, Background fetch is basically designed for downloading/uploading stream of data at regular intervals managed by OS. OS provides the timeframe for your app periodically based on the available system resources. If your app cannot complete the download in 30.0 seconds, with NSURLSession the same task can be resumed next time.

NSURLSession is evolving and it has new priority request model also in iOS8, so I would suggest you to go with NSURLSession. It is asynchronous, it supports authentication handling, it supports separate cache storage, it supports periodic downloads and lot more.