AWSS3 Mobile SDK cancel file download in swift - ios

Question

I have a file download code in my application using AWS Mobile SDK.
That shows an alert with download progress and a cancel button. It is working but I need to cancel download when user hit on alert cancel button. I have tried to cancel the task using the object of AWSS3TransferUtilityDownloadTask and AWSS3TransferUtilityTask.But it seems not working it gives me progress and download completion.
here Is my working code of file download.
Please suggest me how can I Cancel my Download request.
let credentialProvider = AWSStaticCredentialsProvider(accessKey: "MyAccessKey", secretKey: "MySecretKey")
let configuration = AWSServiceConfiguration(region: AWSRegionType.USEast1, credentialsProvider: credentialProvider)
AWSServiceManager.default().defaultServiceConfiguration = configuration
let expression = AWSS3TransferUtilityDownloadExpression()
expression.progressBlock = {(task, progress) in DispatchQueue.main.async(execute: {
// Do something e.g. Update a progress bar.
print("File Progress:",Float(progress.fractionCompleted))
let progress = Float(progress.fractionCompleted)
DispatchQueue.main.async {
if progress == 1.0 {
self.globalAlert.dismiss(animated: true, completion: nil)
}else{
self.globalProgressView!.progress = progress
self.msgProgress = String(Int(progress*100))
}
}
})
}
var completionHandler: AWSS3TransferUtilityDownloadCompletionHandlerBlock?
completionHandler = { (task, URL, data, error) -> Void in
DispatchQueue.main.async(execute: {
// Do something e.g. Alert a user for transfer completion.
// On failed downloads, `error` contains the error object.
//My other code stuff execution
})
}
var refUploadTask: AWSS3TransferUtilityTask?
let transferUtility = AWSS3TransferUtility.default()
transferUtility.downloadData(
fromBucket: Bucket_Name,
key: fileKey,
expression: expression,
completionHandler: completionHandler
).continueWith {
(task) -> AnyObject? in if let error = task.error {
print("Error: \(error.localizedDescription)")
}
if let _ = task.result {
// Do something with downloadTask.
print("download started..")
DispatchQueue.main.async(execute: {
self.globalAlert = UIAlertController(title: "Downloading...", message: "\(String(describing: self.msgProgress))% Completed", preferredStyle: .alert)
let cancelAction = UIAlertAction(title: "Cancel", style: UIAlertAction.Style.default, handler: {
(action : UIAlertAction!) -> Void in
self.refUploadTask.cancel()
})
// Show it to your users
self.globalAlert.addAction(cancelAction)
self.present(self.globalAlert, animated: true, completion: {
// Add your progressbar after alert is shown (and measured)
let margin:CGFloat = 8.0
let rect = CGRect(x: margin, y: 72.0, width: self.globalAlert.view.frame.width - margin * 2.0 , height: 2.0)
self.globalProgressView = UIProgressView(frame: rect)
self.globalProgressView!.tintColor = .blue
self.globalAlert.view.addSubview(self.globalProgressView!)
})
})
}
return nil;
}

Answer 1

You can get the AWSS3TransferUtilityDownloadTask object and cancel the ongoing download.
let awsTask = transferUtility.getDownloadTasks()
if let taskArray = awsTask.result {
for idx in taskArray {
if let task = idx as? AWSS3TransferUtilityDownloadTask {
task.cancel()
}
}
}