protected override Task ProcessImageAsync(MediaHandlerContext context, CachedImage cachedImage, Stream inputStream)
{
var processQuery = new ProcessImageQuery(context.ImageQuery)
{
Source = inputStream,
Format = context.ImageQuery.Format ?? cachedImage.Extension,
FileName = cachedImage.FileName,
DisposeSource = false
};
using (var result = _imageProcessor.ProcessImage(processQuery, false))
{
Logger.DebugFormat($"Processed image '{cachedImage.FileName}' in {result.ProcessTimeMs} ms.", null);
if (!cachedImage.Extension.IsCaseInsensitiveEqual(result.FileExtension))
{
// jpg <> jpeg
cachedImage.Path = Path.ChangeExtension(cachedImage.Path, result.FileExtension);
cachedImage.Extension = result.FileExtension;
}
context.ResultStream = result.OutputStream;
}
return(Task.FromResult(0));
}
public async Task ExecuteAsync(MediaHandlerContext context)
{
if (!IsProcessable(context))
{
return;
}
var query = context.ImageQuery;
var pathData = context.PathData;
var cachedImage = ImageCache.Get(context.MediaFileId, pathData, query);
if (!pathData.Extension.IsCaseInsensitiveEqual(cachedImage.Extension))
{
// The query requests another format.
// Adjust extension and mime type fo proper ETag creation.
pathData.Extension = cachedImage.Extension;
pathData.MimeType = cachedImage.MimeType;
}
var exists = cachedImage.Exists;
if (exists && cachedImage.FileSize == 0)
{
// Empty file means: thumb extraction failed before and will most likely fail again.
// Don't bother proceeding.
context.Exception = ExceptionFactory.ExtractThumbnail(cachedImage.FileName);
context.Executed = true;
return;
}
if (!exists)
{
// Lock concurrent requests to same resource
using (await KeyedLock.LockAsync("ImageHandlerBase.Execute." + cachedImage.Path))
{
ImageCache.RefreshInfo(cachedImage);
// File could have been processed by another request in the meantime, check again.
if (!cachedImage.Exists)
{
// Call inner function
var sourceFile = context.SourceFile;
if (sourceFile == null || sourceFile.Size == 0)
{
context.Executed = true;
return;
}
var inputStream = sourceFile.OpenRead();
if (inputStream == null)
{
context.Exception = ExceptionFactory.ExtractThumbnail(sourceFile.Path, T("Admin.Media.Exception.NullInputStream"));
context.Executed = true;
return;
}
try
{
await ProcessImageAsync(context, cachedImage, inputStream);
}
catch (Exception ex)
{
Logger.Error(ex);
if (ex is ExtractThumbnailException)
{
// Thumbnail extraction failed and we must assume that it always will fail.
// Therefore we create an empty file to prevent repetitive processing.
using (var memStream = new MemoryStream())
{
await ImageCache.PutAsync(cachedImage, memStream);
}
}
context.Exception = ex;
context.Executed = true;
return;
}
finally
{
if (inputStream != null)
{
inputStream.Dispose();
}
}
if (context.ResultImage != null)
{
ImageCache.Put(cachedImage, context.ResultImage);
context.ResultFile = cachedImage.File;
}
context.Executed = true;
return;
}
}
}
// Cached image existed already
context.ResultFile = cachedImage.File;
context.Executed = true;
}
protected abstract Task ProcessImageAsync(MediaHandlerContext context, CachedImage cachedImage, Stream inputStream);
protected abstract bool IsProcessable(MediaHandlerContext context);
protected override bool IsProcessable(MediaHandlerContext context)
{
return(context.ImageQuery.NeedsProcessing(true) && _imageProcessor.IsSupportedImage(context.PathData.Extension));
}
