/// <summary>
/// Prepares a BITS job adding the files and creating the required folders.
/// </summary>
/// <param name="backgroundCopyJob">The BITS job information.</param>
/// <param name="task">The DownloadTask instace.</param>
private static void PrepareJob(IBackgroundCopyJob backgroundCopyJob, DownloadTask task)
{
Guid jobID;
backgroundCopyJob.GetId(out jobID);
task.JobId = jobID;
DownloadFile sourceFile = task.DownloadItem.File;
string src = sourceFile.Source;
// to defend against config errors, check to see if the path given is UNC;
// if so, throw immediately there's a misconfiguration. Paths to BITS must be HTTP or HTTPS
if (FileHelper.IsUncPath(src))
{
Exception ex = new DownloaderException("Download location must be HTTP or HTTPS URL");
Logger.Error(ex);
throw ex;
}
//TODO: how about duplicate filenames?
string dest = Path.Combine(task.DownloadFilesBase, sourceFile.LocalName);
if (!Directory.Exists(Path.GetDirectoryName(dest)))
{
Directory.CreateDirectory(Path.GetDirectoryName(dest));
}
// add this file to the job
backgroundCopyJob.AddFile(src, dest);
}
/// <summary>
/// Waits for the download to complete, for the synchronous usage of the downloader.
/// </summary>
/// <param name="backgroundCopyJob">The job instance reference.</param>
/// <param name="maxWaitTime">The maximum wait time.</param>
/// <param name="task">The updater task instance.</param>
private void WaitForDownload(DownloadTask task, IBackgroundCopyJob backgroundCopyJob, TimeSpan maxWaitTime)
{
bool isCompleted = false;
bool isSuccessful = false;
try
{
Guid jobID;
backgroundCopyJob.GetId(out jobID);
// set endtime to current tickcount + allowable # milliseconds to wait for job
double endTime = Environment.TickCount + maxWaitTime.TotalMilliseconds;
while (!isCompleted)
{
BG_JOB_STATE state;
backgroundCopyJob.GetState(out state);
switch (state)
{
case BG_JOB_STATE.BG_JOB_STATE_SUSPENDED:
{
OnDownloadStarted(new TaskEventArgs(task));
backgroundCopyJob.Resume();
break;
}
case BG_JOB_STATE.BG_JOB_STATE_ERROR:
{
// use utility to:
// a) get error info
// b) report it
// c) cancel and remove copy job
OnJobError(task, backgroundCopyJob, null, null);
// complete loop, but DON'T say it's successful
isCompleted = true;
break;
}
case BG_JOB_STATE.BG_JOB_STATE_TRANSIENT_ERROR:
{
// NOTE: during debugging + test, transient errors resulted in complete job failure about 90%
// of the time. Therefore we treat transients just like full errors, and CANCEL the job
// use utility to manage error etc.
OnJobError(task, backgroundCopyJob, null, null);
// stop the loop, set completed to true but not successful
isCompleted = true;
break;
}
case BG_JOB_STATE.BG_JOB_STATE_TRANSFERRING:
{
OnJobModification(task, backgroundCopyJob);
break;
}
case BG_JOB_STATE.BG_JOB_STATE_TRANSFERRED:
{
OnJobTransferred(task, backgroundCopyJob);
isCompleted = true;
isSuccessful = true;
break;
}
default:
break;
}
if (isCompleted)
{
break;
}
if (endTime < Environment.TickCount)
{
var ex = new DownloaderException("Download attempt timed out");
OnJobError(task, backgroundCopyJob, null, ex);
break;
}
// Avoid 100% CPU utilisation with too tight a loop, let download happen.
Thread.Sleep(TimeToWaitDuringSynchronousDownload);
}
if (!isSuccessful)
{
// create message + error, package it, publish
var ex =
new DownloaderException(String.Format("Download attempt for {0} failed",
task.DownloadItem.ItemId));
OnJobError(task, backgroundCopyJob, null, ex);
}
}
catch (ThreadInterruptedException tie)
{
// if interrupted, clean up job
OnJobError(task, backgroundCopyJob, null, tie);
}
}
protected override void When()
{
Exception = new DownloaderException("TESTMESSAGE", InnerException);
}