/// <summary>
/// Downloads the latest version of this package. If a version is already in the local store, it will be deleted first.
/// </summary>
/// <param name="displayErrorMessage">Indicates whether to display error message boxes when an error occurs.</param>
/// <returns>A task that completes when the latest version has been downloaded.</returns>
/// <remarks>
/// This method will invoke, from a worker thread, <see cref="BeforeDownload"/> before doing anything, and <see cref="AfterDownload"/>
/// if the download successfully completed without exception. In every case, it will also invoke <see cref="UpdateVersionsFromStore"/>
/// before completing.
/// </remarks>
protected Task Download(bool displayErrorMessage)
{
BeforeDownload();
return(Task.Run(async() =>
{
IsProcessing = true;
// Uninstall previous version first, if it exists
if (LocalPackage != null)
{
try
{
CurrentProcessStatus = null;
using (var progressReport = new ProgressReport(Store, ServerPackage))
{
progressReport.ProgressChanged += (action, progress) => { Dispatcher.InvokeAsync(() => { UpdateProgress(action, progress); }).Forget(); };
progressReport.UpdateProgress(ProgressAction.Delete, -1);
await Store.UninstallPackage(LocalPackage, progressReport);
CurrentProcessStatus = null;
}
}
catch (Exception e)
{
if (displayErrorMessage)
{
var message = $"{UninstallErrorMessage}{e.FormatSummary(true)}";
await ServiceProvider.Get <IDialogService>().MessageBox(message, MessageBoxButton.OK, MessageBoxImage.Error);
await UpdateVersionsFromStore();
IsProcessing = false;
return;
}
IsProcessing = false;
throw;
}
}
// Then download and install the latest version.
bool downloadCompleted = false;
try
{
using (var progressReport = new ProgressReport(Store, ServerPackage))
{
progressReport.ProgressChanged += (action, progress) => { Dispatcher.InvokeAsync(() => { UpdateProgress(action, progress); }).Forget(); };
progressReport.UpdateProgress(ProgressAction.Install, -1);
MetricsHelper.NotifyDownloadStarting(ServerPackage.Id, ServerPackage.Version.ToString());
await Store.InstallPackage(ServerPackage.Id, ServerPackage.Version, progressReport);
downloadCompleted = true;
MetricsHelper.NotifyDownloadCompleted(ServerPackage.Id, ServerPackage.Version.ToString());
}
AfterDownload();
}
catch (Exception e)
{
if (!downloadCompleted)
{
MetricsHelper.NotifyDownloadFailed(ServerPackage.Id, ServerPackage.Version.ToString());
}
// Rollback: try to delete the broken package (i.e. if it is installed with NuGet but had a failure during Install scripts)
try
{
var localPackage = Store.FindLocalPackage(ServerPackage.Id, ServerPackage.Version);
if (localPackage != null)
{
await Store.UninstallPackage(localPackage, null);
}
}
catch
{
// Note: quite a bad state: rollback (uninstall) failed
// we don't display the message to not confuse the user even more with an intermediate uninstall error message before the install error message
}
if (displayErrorMessage)
{
var message = $"{InstallErrorMessage}{e.FormatSummary(true)}";
await ServiceProvider.Get <IDialogService>().MessageBox(message, MessageBoxButton.OK, MessageBoxImage.Error);
return;
}
throw;
}
finally
{
await UpdateVersionsFromStore();
IsProcessing = false;
}
}));
}