Im using NSURLSession which is preferred according to this thread. How to make an HTTP request in Swift?
let url = NSURL(string: "http://www.stackoverflow.com")
let task = NSURLSession.sharedSession().dataTaskWithURL(url!) {(data, response, error) in
println(NSString(data: data, encoding: NSUTF8StringEncoding))
}
task.resume()
My only problem is when user taps twice and I want to cancel the first request. I have tried task.cancel() but the print statement is still executed (namely right after .cancel() with NSDomainError). How do I safely cancel this request (NSURLSessionDataTask), without firing the print statement, or is it even possible?
EDIT: Just to be clear. The URL could be the same and I want to cancel the first request.
This is how I solved the problem. When task.cancel() is performed, the print statement wont be executed. Seems a little hacky to check against a string so if anyone has a better solution I will accept that one.
let url = NSURL(string: "http://www.stackoverflow.com")
let task = NSURLSession.sharedSession().dataTaskWithURL(url!) {(data, response, error) in
if (error?.userInfo?["NSLocalizedDescription"] as? String) == "cancelled"
{
return
}
println(NSString(data: data, encoding: NSUTF8StringEncoding))
}
task.resume()
I hope this is something you can use:
class ViewController: UIViewController , NSURLSessionDownloadDelegate {
var download : NSURLSessionDownloadTask?
var backgroundSession : NSURLSession?
override func viewDidLoad() {
super.viewDidLoad()
let sessionConfiguration : NSURLSessionConfiguration = NSURLSessionConfiguration.backgroundSessionConfigurationWithIdentifier("CustomBackgroundIdentifier")
backgroundSession = NSURLSession(configuration: sessionConfiguration, delegate: self, delegateQueue: NSOperationQueue.mainQueue())
var btn = UIButton(frame: CGRectMake(0, 0, 100, 100))
btn.backgroundColor = UIColor.redColor()
btn.addTarget(self, action: "startDownload", forControlEvents: UIControlEvents.TouchDown)
self.view.addSubview(btn)
var btn2 = UIButton(frame: CGRectMake(0, 120, 100, 100))
btn2.backgroundColor = UIColor.blueColor()
btn2.addTarget(self, action: "cancelDownload", forControlEvents: UIControlEvents.TouchDown)
self.view.addSubview(btn2)
}
func startDownload() {
if download == nil {
if let url = NSURL(string: "http://www.stackoverflow.com") {
download = backgroundSession?.downloadTaskWithURL(url)
download?.resume()
}
} else {
resumeDownload()
}
}
func pauseDownload() {
if download != nil {
download?.suspend()
}
}
func resumeDownload() {
if download != nil {
download?.resume()
}
}
func cancelDownload() {
if download != nil {
download?.cancel()
}
}
func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didFinishDownloadingToURL location: NSURL) {
println("Session %@ download task %@ finished downloading to URL %@\n",
session, downloadTask, location)
}
func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
println("downloaded: %i",totalBytesWritten)
}
}
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