Btukfyl

I'm using URLSession to get the response from the API's in my iPhone app. In my case, I'm hitting around 10 requests of a same api at a time using Asynchronous API calling and I'm getting the response for all the requests. Now from those responses how can I find which response belongs to which request? Any help appreciated.

You have many ways to achieve this.

1 - Basically, if you call your client function with an identifier, you will be able to retrieve it in your completion block:

func call(with identifier: String, at url: URL) {

    URLSession.shared.dataTask(url: url) { (_, _, _) in

        print(identifier)

    }.resume()

}

2 - You can also use the taskIdentifier of an URLSessionDataTask. But to do this, you will need to use the delegate of your custom URLSession:

self.session = URLSession(configuration: URLSessionConfiguration.default,

                          delegate: self,

                          delegateQueue: nil)

then you will not use a completion block but the delegate function instead:

func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive response: URLResponse, completionHandler: @escaping (URLSession.ResponseDisposition) -> Void) {

    print(dataTask.taskIdentifier)

}

(of course you need to know which task identifier has been set for which URLSessionDataTask)

3 - If you need to access your identifier from your completion block, you can write a function which will happened it in the list of the parameter of the default completion block:

func dataTask(session: URLSession,

              url: URL,

              identifier: String,

              completionBlock: @escaping (String, Data?, URLResponse?, Error?) -> Void) -> URLSessionDataTask {

    return session.dataTask(with: url) { (data, response, error) in

        completionBlock(identifier, data, response, error)

    }

}

4 - If you need to have a custom identifier in a URLSessionDataTask object, you can add it using extension and associated object:

extension URLSessionDataTask {

    var identifier: String? {

        get {

            let identifier = objc_getAssociatedObject(self, &kIdentiferId)

            if let id = identifier as? String {

                return id

            } else {

                return nil

            }

        }

        set {

            objc_setAssociatedObject(self, &kIdentiferId, newValue, .OBJC_ASSOCIATION_RETAIN)

        }

    }

}



private var kIdentiferId: Int8 = 100

Then you can use it like this:

let task = session.dataTask(url: url)

task.identifier = "hello"