The Download is not Working in the background mode even if i entitled all the necessary permission for the application it only works when the app is connected to xcode due to xcode keep the session alive but if try after removing the connection from the xcode the app not able to keep the download after 45 sec what may be the reason
my code
var request = URLRequest(url: url)
request.httpMethod = "GET"
let bearerToken = SyncManager.accessToken
request.setValue("Bearer \(bearerToken)", forHTTPHeaderField: "Authorization")
let uniqueIdentifier = "\(self.vdmsId)_\(UUID().uuidString)"
backgroundTaskID = UIApplication.shared.beginBackgroundTask { [weak self] in
if let taskID = self?.backgroundTaskID {
UIApplication.shared.endBackgroundTask(taskID)
self?.backgroundTaskID = .invalid
}
}
let CursessionConfig = URLSessionConfiguration.background(withIdentifier: uniqueIdentifier)
CursessionConfig.isDiscretionary = false
CursessionConfig.sessionSendsLaunchEvents = true
CursessionConfig.shouldUseExtendedBackgroundIdleMode = true
// Set timeout intervals
CursessionConfig.timeoutIntervalForResource = 24 * 60 * 60 // 24 hours
CursessionConfig.timeoutIntervalForRequest = 60 * 60 // 1 hour
let Cursession = URLSession(configuration: CursessionConfig, delegate: self, delegateQueue: nil)
self.CurInstanceSession = Cursession
self.session = Cursession
if SyncManager.activeSessions == nil {
SyncManager.activeSessions = [URLSession]()
}
SyncManager.activeSessions?.append(Cursession)
self.downloadCompletionHandler = completion
let CurdownloadTask = Cursession.downloadTask(with: request)
CurdownloadTask.resume()
is there any solutions and i have entitled all the neccessary permisssions like background fetch, process and i also tries with the UIApplication.shared.beginBackgroundTask but after 45 sec it gets terminated all of the suden what may be the issue
Let me start by explaining what's going on here:
it only works when the app is connected to xcode due to xcode keep the session alive
To allow the debugger to function Xcode disable app suspension, allowing your app to run in the background indefinitely. As you're experiencing, this will heavily distort the behavior of many of our background APIs, so background app testing needs to be done without Xcode being involved.
That leads to here:
but if try after removing the connection from the xcode the app not able to keep the download after 45 sec what may be the reason
Yes, this is basically what I'd expect to happen. What the background URL session actually does is transfer your connection configuration information to nsurlsessiond so that nsurlsesiond can perform the actual transfer, NOT your app. As part of that process, the system also tries to perform that work when it unlikely to disrupt the user. That's what happened above- the transfer stayed active while your app was awake but stopped it shortly after your app suspended to minimize any user disruption. It will that resume the transfer "later" when the risk of user disruption is minimal.
Lastly, keep in mind that force quitting the app will also stop background transfer, as the force quit indicates that the user doesn't want your app to run. When I'm specifically trying to test how one of our background APIs behave, the flow I use is this:
-
Install and run the app through Xcode.
-
Stop the app through Xcode.
-
Swipe up force quit/remove the app from the app switcher.
-
Launch the app again and perform any configuration or setup work.
-
Background the app.
Every step of that flow isn't necessarily required, but it's the safest flow that ensure you're closely replicating what a user run would look like and that Xcode isn't going to disrupt anything.
__
Kevin Elliott
DTS Engineer, CoreOS/Hardware
