public override async Task Download(IPhilomenaImage downloadItem, CancellationToken cancellationToken = default, IProgress <PhilomenaImageDownloadProgressInfo>?progress = null)
{
bool shouldDownloadImage = _shouldDownloadImage(downloadItem);
_logger.LogDebug("Condition for downloading image {ImageId}: {ConditionResult}", downloadItem.Id, shouldDownloadImage);
if (shouldDownloadImage)
{
await _downloader.Download(downloadItem, cancellationToken, progress);
}
}
public async Task BeginDownload(
CancellationToken cancellationToken = default,
IProgress <PhilomenaImageSearchProgressInfo>?searchProgress = null,
IProgress <PhilomenaImageSearchDownloadProgressInfo>?searchDownloadProgress = null,
IReadOnlyCollection <IProgress <PhilomenaImageDownloadProgressInfo> >?individualDownloadProgresses = null)
{
ConcurrentBag <IProgress <PhilomenaImageDownloadProgressInfo> >?availableProgress = null;
if (individualDownloadProgresses is not null)
{
// Ensure enough progress entries are provided
if (individualDownloadProgresses.Count != _maxDownloadThreads)
{
throw new ArgumentException($"Expected {_maxDownloadThreads} progress entries, but {individualDownloadProgresses.Count} were provided.", nameof(individualDownloadProgresses));
}
// Copy progress entries to a thread safe structure
availableProgress = new ConcurrentBag <IProgress <PhilomenaImageDownloadProgressInfo> >(individualDownloadProgresses);
}
// Track images downloaded
int imagesDownloaded = 0;
// The total images to download is unknown until the image search reports it
int totalImages = -1;
// An object to lock on for reporting the search download progress
object searchDownloadProgressLock = new object();
// Wrap the image search progress to track the total number of images to download
IProgress <PhilomenaImageSearchProgressInfo> wrappedSearchProgress = new SyncProgress <PhilomenaImageSearchProgressInfo>(progress =>
{
totalImages = progress.TotalImages;
searchProgress?.Report(progress);
});
// Download the images using as many threads as configured
IAsyncEnumerable <IPhilomenaImage> imagesToDownload = _imageSearch.BeginSearch(cancellationToken, wrappedSearchProgress);
await imagesToDownload.ParallelForEachAsync
(
async (image) =>
{
_logger.LogDebug("Downloading image {ImageId}", image.Id);
// Take a progress slot for this image
IProgress <PhilomenaImageDownloadProgressInfo>?imageProgress = null;
availableProgress?.TryTake(out imageProgress);
// Download the image
await _imageDownloader.Download(image, cancellationToken, imageProgress);
// Report search download progress
lock (searchDownloadProgressLock)
{
imagesDownloaded++;
searchDownloadProgress?.Report(new()
{
ImagesDownloaded = imagesDownloaded,
ImagesTotal = totalImages
});
}
// Make individual download progress available if one was taken
if (imageProgress is not null)
{
availableProgress !.Add(imageProgress);
}
},
maxDegreeOfParallelism : _maxDownloadThreads,
cancellationToken : cancellationToken
);
}