ios - Ideal value for the URLSession - delegateQueue in Swift

Question

We have a common Requesthandler.swift file which handles get, post http methods. We are using this file accross the App to have http request. What should be the value for the delegateQueue, when we initialising the URLSession.

let session = URLSession(configuration: config, delegate: self, delegateQueue:OperationQueue.main)

question from:https://stackoverflow.com/questions/65558062/ideal-value-for-the-urlsession-delegatequeue-in-swift

Answer 1

If you use it across the app for all http that is the correct way to do it. However, I would suggest not to create your own session. There is already something exactly for that, which is URLSession.shared, albeit with (just a few) limitations as discussed in the docs.

If you can live with the limitations great - use the shared session; otherwise use nil as Rob suggested or if you DIY the queue then you do NOT want to use main as your delegate queue. You definitely want a background queue here. If you DIY then you'd probably create a singleton queue and use that for all requests and configure it according to taste (and make it serial - see Rob's answer).

Finally, since the delegate will call the completion on the delegate queue, which is NOT main, you should switch to main in the completion whenever you need to update UI, so there will probably be a lot of switching to main there. That is not wrong nor telling you to use main as queue.