/// <summary>
/// The actual functionality to download with optional hash verification
/// subclasses that wish to return the contents of the downloaded file
/// or do something else with it can override this instead of RunWithReturn.
/// If you do, you must call RaiseOnStart()/RaiseOnEnd()
/// </summary>
/// <param name="success"></param>
/// <returns></returns>
protected virtual string RunDownload(bool success)
{
Exception exception = null;
var attempts = 0;
bool result = false;
do
{
if (Token.IsCancellationRequested)
{
break;
}
exception = null;
try
{
Logger.Trace($"Download of {Url} to {Destination} Attempt {attempts + 1} of {RetryCount + 1}");
using (var destinationStream = fileSystem.OpenWrite(Destination, FileMode.Append))
{
result = Utils.Download(Logger, Url, destinationStream,
(value, total) =>
{
UpdateProgress(value, total);
return(!Token.IsCancellationRequested);
});
}
if (result && ValidationHash != null)
{
var md5 = fileSystem.CalculateFileMD5(TargetDirectory);
result = md5.Equals(ValidationHash, StringComparison.CurrentCultureIgnoreCase);
if (!result)
{
Logger.Warning($"Downloaded MD5 {md5} does not match {ValidationHash}. Deleting {TargetDirectory}.");
fileSystem.FileDelete(TargetDirectory);
}
else
{
Logger.Trace($"Download confirmed {md5}");
break;
}
}
}
catch (Exception ex)
{
exception = ex;
}
} while (attempts++ < RetryCount);
if (!result)
{
Token.ThrowIfCancellationRequested();
throw new DownloadException("Error downloading file", exception);
}
return(Destination);
}
