Is there a way to use NSURLProtocol in a NSURLSession with custom config?

Question

I have a NSURLSession that runs in a background queue. I'm adding my NSURLProtocol subclass to the NSURLsessionConfiguration.protocolClases but the override class func canInitWithRequest(request: NSURLRequest) -> Bool never gets called.

This is how I'm adding my NSURLProtocol

let configuration = NSURLSessionConfiguration.defaultSessionConfiguration()
configuration.protocolClasses!.append(MockNetwork)
urlSession = NSURLSession(configuration: configuration, delegate: self, delegateQueue: operationQueue)

Also I tried with the session not running on background doing but also didn't work:

let configuration = NSURLSessionConfiguration.defaultSessionConfiguration()
configuration.protocolClasses!.append(MockNetwork)
urlSession = NSURLSession(configuration: configuration)

As this was not working I just tried:

urlSession = NSURLSession.sharedSession()

And calling this in my AppDelegate

NSURLProtocol.registerClass(MockNetwork)

This does work, what am I doing wrong?!

Tape

This does work, what am I doing wrong? Answer: Nothing :) – Shrewmouse

but I can't make it work when using a custom config in a background queue... this is driving me CRAZY – Tape

Answer 1

After spending some more hours trying to find out why this wasn't working I found the way of doing it.

Instead of:

configuration.protocolClasses?.append(MockNetwork.self)

Do:

var protocolClasses = [AnyClass]()
protocolClasses.append(MockNetwork.self)

let configuration = URLSessionConfiguration.default
configuration.protocolClasses = protocolClasses

After that change everything worked and not necessary to URLProtocol.registerClass(MockNetwork.self)

Tape

You would still have to register your custom protocol through NSURLProtocol.registerClass(MockNetwork) in case you were trying to intercept web view requests. – Potsherd

protocolClasses uses AnyClass not AnyObject. Your array would need to be [AnyClass]() instead. – Guenzi