Ios – Add operation in queue while requesting ASIHTTPRequest or AFNetworking

afnetworkingasihttprequestiosobjective c

I want to add operation into executing request. I read about ASINetworkQueue, but it adds all operation and run it all. but i want to add operation into running queue.

Is this possible? using ASIHTTPRequest or AFNetworking i don't mind, as long as i get what i intend to do.

EDIT

It shows below error while i try to add another request.

[ASINetworkQueue addOperation:]: operation is executing and cannot be enqueued'

Best Answer

From the apple documentation for addOperation: it is clear that you cannot add an operation which is executing into a NSOperationQueue.

This is what mentioned there,

An operation object can be in at most one operation queue at a time and this method throws an NSInvalidArgumentException exception if the operation is already in another queue. Similarly, this method throws an NSInvalidArgumentException exception if the operation is currently executing or has already finished executing.

That is the default behavior of NSOperationQueue. You need to make sure that the NSOperation is not executing before adding to queue. There are various properties such as isExecuting, isFinished etc.. to check this.

Related Solutions

Ios – What major ASIHTTPRequest features is AFNetworking missing

I loved ASIHTTPRequest and I was sad to see it go. However, the developer of ASI was right, ASIHTTPRequest has become so large and bloated that even he couldn't devote time to bring it to par with newest features of iOS and other frameworks. I moved on and now use AFNetworking.

That said, I must say that AFNetworking is much more unstable than ASIHTTP, and for the things I use it for, it needs refinement.

I often need to make HTTP requests to 100 HTTP sources before I display my results on screen, and I have put AFHTTPNetworkOperation into an operation queue. Before all results are downloaded, I want to be able to cancel all operations inside the operation queue and then dismiss the view controller that holds the results.

That doesn't always work.

I get crashes at random times with AFNetworking, while with ASIHTTPRequest, this operations were working flawlessly. I wish I could say which specific part of AFNetworking is crashing, as it keeps crashing at different points (however, most of these times the debugger points to the NSRunLoop that creates an NSURLConnection object). So, AFNetworking needs to mature in order to be considered as complete as ASIHTTPRequest was.

Also, ASIHTTPRequests supports client authentication, which AFNetworking lacks at the moment. The only way to implement it is to subclass AFHTTPRequestOperation and to override NSURLConnection's authentication methods. However, if you start getting involved with NSURLConnection, you will notice that putting NSURLConnection inside an NSOperation wrapper and writing completion blocks isn't so hard as it sounds and you will start thinking what keeps you from dumping 3rd party libraries.

ASI uses a whole different approach, since it uses CFNetworking (lower-level foundation frameworks based on C) to make downloading and file uploading possible, skipping NSURLConnection completely, and touching concepts most of us OS X and iOS developers are too afraid to. Because of this, you get better file uploading and downloading, even web page caches.

Which do i prefer? It's hard to say. If AFNetworking matures enough, I will like it more than ASI. Until then, I can't help but admire ASI, and the way it became one of the most used frameworks of all time for OS X and iOS.

EDIT: I think it's time to update this answer, as things have changed a bit after this post.

This post was written some time ago, and AFNetworking has matured enough. 1-2 months ago AF posted a small update for POST operations that was my last complaint about the framework (a small line ending fault was the reason that echonest uploads failed with AF but were completed fine with ASI). Authentication is not an issue with AFnetworking, as for complex authentication methods you can subclass the operation and make your own calls and AFHTTPClient makes basic authentication a piece of cake. By subclassing AFHTTPClient you can make an entire service consumer in little time.

Not to mention the absolutely necessary UIImage additions that AFNetworking offers. With blocks and custom completion blocks and some clever algorithm, you can make table views with asynchronous image downloading and cell filling pretty easily, whereas in ASI you had to make operation queues for bandwidth throttling and mind yourself to cancel and resume the operation queue according to table view visibility, and stuff like that. Development time of such operations has been halved.

I also love the success and failure blocks. ASI has only a completion block (which is actually the completion block of NSOperation). You had to check whether you had an error on completion and act accordingly. For complex web services, you could get lost in all the "ifs" and "elses"; In AFNetworking, things are much more simple and intuitive.

ASI was great for its time, but with AF you can change the way you handle web services completely in a good way, and make scalable applications more easily. I really believe that there is no reason whatsoever to stick with ASI anymore, unless you want to target iOS 3 and below.

Ios – ASIHTTPRequest vs AFNetworking framework

Update (September 2013)

It's been nearly two years since I originally wrote this answer, and quite a lot has changed. AFNetworking is about to go into version 2.0 and has a thriving developer community, whereas ASIHTTPRequest is pretty much dead. Additionally, AFNetworking has dozens of great helper libraries and classes available for handling things like OAuth, Amazon S3, and the like. It's so popular that there's several books available on it.

Given this, there's no reason at all to keep using ASIHTTPRequest. My original answer is below, so if you're still interested do read on - just bear in mind I would now recommend without a doubt not using ASIHTTPRequest and going with something more modern (namely, AFNetworking, but other options are available).

Original Answer (December 2011)

How much time have you got? Here's my thoughts, although as a subjective question I don't think there's a right or wrong answer.

I lead a development team that works on commercial apps for sizeable clients, and some of my colleagues are always on the look-out for new libraries that can make things easier. Currently I guess the vast majority of our networking uses ASIHTTP. We took a look at AFNetworking about six months ago, and decided at the time we'd stick with what we know. ASI has been around for a while, and there is far more documentation and helpful advice available online for it. It is a solid codebase, and been around long enough to have gained a lot of traction and respect.

That said (and hopefully people who disagree with everything I've said above will read on!), I think if you're starting afresh now is the time to move on to something else. Even the developer of ASI thinks so. Given all of the changes that have come with iOS 5, I think a modern actively maintained framework like AFNetworking (and there are other options, like RestKit) is a good choice.

Now, you're right to say some people have trouble using AFNetworking in their application. But equally, a quick google reveals many people who had problems with ASI (valid or not)! I think whatever framework you go with, someone somewhere will have had trouble with it, either through something genuine wrong with the framework or their own limitations.

So with all this in mind I think I'd dive in to AFNetworking, and see how you get on! One of my new year resolutions will be to migrate over to a new networking library, and I think it will probably be AFNetworking.

From Author's Comment:

A little update: I've actually really enjoyed using AFNetworking, and in many ways it's considerably better (probably not the right word: 'refined', maybe) than ASI. That said, you shouldn't go into it expecting a 'like for like' replacement, and there are certain things you may want to consider other options for (Amazon S3, which ASI supported out of the box for example). But I'm generally really pleased, and find it a clear, well documented library. So if you're looking to move from ASI to something else, you really can't go wrong with AFNetworking...