swift, alamofire cancel previous request

Question

I have an NetworkRequest class, where all my alamofire requests made:

    class NetworkRequest {
        static let request = NetworkRequest()

        var currentRequest: Alamofire.Request?

        let dataManager = DataManager()
        let networkManager = NetworkReachabilityManager()
        let priority = DISPATCH_QUEUE_PRIORITY_DEFAULT

        func downloadData<T: Film>(slug: String, provider: String, section: String, dynamic: String, anyClass: T, completion: ([T]?) -> Void ) {
            var token: String = ""

            if LOGGED_IN == true {
                token = "\(NSUserDefaults.standardUserDefaults().valueForKey(TOKEN)!)"
            }

            let headers = [
                "Access": "application/json",
                "Authorization": "Bearer \(token)"
            ]

            let dataUrl = "\(BASE_URL)\(slug)\(provider)\(section)\(dynamic)"
            print(headers)
            print(dataUrl)

            if networkManager!.isReachable {

                currentRequest?.cancel()

                dispatch_async(dispatch_get_global_queue(priority, 0)) {

                    if let url = NSURL(string: dataUrl) {
                        let request = Alamofire.request(.GET, url, headers: headers)

                        request.validate().responseJSON { response in
                            switch response.result {
                            case .Success:
                                if let data = response.result.value as! [String: AnyObject]! {
                                    let receivedData = self.dataManager.parseDataToFilms(data, someClass: anyClass)
                                    completion(receivedData)
                                }

                            case .Failure(let error):
                                print("Alamofire error: \(error)")

                                if error.code == 1001 {
                                    self.goToNoConnectionVC()
                                }

                                print("canceled")
                            }

                        }
                    }
                }
            } else {
                goToNoConnectionVC()
            }
        }
}

And I need to cancel previous downloadData request, when the new one starts, tried to cancel using currentRequest?.cancel(), but it doesn't help.

Already tried to cancelOperations using NSOperationsBlock, but it doesn't cancels current operation.

I block UI now, so that user can't send another request. But this is not correct, causes some errors later...

Pls, help

Answer 1

Found needed solution:

func stopAllSessions() {
    Alamofire.Manager.sharedInstance.session.getAllTasksWithCompletionHandler { tasks in
        tasks.forEach { $0.cancel() }
    }
}

Update for Alamofire 5

func stopAllSessions() {
    AF.session.getTasksWithCompletionHandler { (sessionDataTask, uploadData, downloadData) in
        sessionDataTask.forEach { $0.cancel() }
        uploadData.forEach { $0.cancel() }
        downloadData.forEach { $0.cancel() }
    }
}