Get NSData after completion of NSURLSession - ios

Question

I am fetching data using NSURLSession but I don't know how to get the data back once the download is complete my code :
class ViewController: UIViewController,NSURLSessionDelegate,NSURLSessionDataDelegate{
#IBOutlet var imageView: UIImageView!
#IBOutlet weak var progress: UIProgressView!
var buffer:NSMutableData = NSMutableData()
var session:NSURLSession?
var dataTask:NSURLSessionDataTask?
let url = NSURL(string:"https://initiate.alphacoders.com/download/wallpaper/566046/images7/jpg/37100/1353" )!
var expectedContentLength = 0
var downloadedImage = UIImage()
var downloadedData = NSData()
override func viewDidLoad() {
super.viewDidLoad()
progress.progress = 0.0
let configuration = NSURLSessionConfiguration.defaultSessionConfiguration()
let manqueue = NSOperationQueue.mainQueue()
session = NSURLSession(configuration: configuration, delegate:self, delegateQueue: manqueue)
dataTask = session?.dataTaskWithRequest(NSURLRequest(URL: url))
dataTask?.resume()
// Do any additional setup after loading the view, typically from a nib.
}
func URLSession(session: NSURLSession, dataTask: NSURLSessionDataTask, didReceiveResponse response: NSURLResponse, completionHandler: (NSURLSessionResponseDisposition) -> Void) {
//here you can get full lenth of your content
expectedContentLength = Int(response.expectedContentLength)
print(expectedContentLength)
completionHandler(NSURLSessionResponseDisposition.Allow)
}
func URLSession(session: NSURLSession, dataTask: NSURLSessionDataTask, didReceiveData data: NSData) {
if progress.progress > 0.99 {
downloadedImage = UIImage(data: data , scale: 1)!
}
buffer.appendData(data)
print("checking")
let percentageDownloaded = Float(buffer.length) / Float(expectedContentLength)
progress.progress = percentageDownloaded
}
func URLSession(session: NSURLSession, task: NSURLSessionTask, didCompleteWithError error: NSError?) {
//use buffer here.Download is done
progress.progress = 1.0// download 100% complete
imageView.image = downloadedImage
}
}
I tried to get the data from func URLSession(session: NSURLSession, dataTask: NSURLSessionDataTask, didReceiveData but at didReceiveData my file is not yet fully downloaded and i don't know how to get the data from didCompleteWithError function , am new in swift and still figuring out things here ,
If anybody knows here what I am missing or what should I do then please tell me, any guidance will be so appreciated and helpful.

Answer 1

- URLSession:downloadTask:didFinishDownloadingToURL:
Is something you are missing.
Called to inform the delegate that a download task has finished downloading.
This method gives you a file URL for the temporary file (The third parameter). Because the file is temporary, you must either open the file for reading or move it to a permanent location in your app’s sandbox container directory before returning from this delegate method.
Find more here.
EDIT 1: To check the progress override following method:
- URLSession:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite:
EDIT 2: Okay I see now. Make following changes and see if it works?:
Let your class conform NSURLSessionDownloadDelegate
Change dataTask = session?.dataTaskWithRequest(NSURLRequest(URL: url)) to dataTask = session?.downloadTaskWithURL(NSURLRequest(URL: url))
That should make you download the file.