/// <summary> /// Generates the resized image to disk (if needed), then rewrites the request to that location. /// Perform 404 checking before calling this method. Assumes file exists. /// Called during PostAuthorizeRequest /// </summary> /// <param name="context"></param> /// <param name="ra"></param> /// <param name="vf"></param> protected virtual async Task HandleRequest(HttpContext context, HttpModuleRequestAssistant ra, IVirtualFileAsync vf) { if (!ra.CachingIndicated && !ra.ProcessingIndicated) { ra.ApplyRewrittenPath(); //This is needed for both physical and virtual files; only makes changes if needed. if (vf != null) { ra.AssignSFH(); //Virtual files are not served in .NET 4. } return; } //Communicate to the MVC plugin this request should not be affected by the UrlRoutingModule. context.Items[conf.StopRoutingKey] = true; context.Items[conf.ResponseArgsKey] = ""; //We are handling the request ra.EstimateResponseInfo(); //Build CacheEventArgs var e = new AsyncResponsePlan(); var modDate = (vf == null) ? System.IO.File.GetLastWriteTimeUtc(ra.RewrittenMappedPath) : (vf is IVirtualFileWithModifiedDateAsync ? await((IVirtualFileWithModifiedDateAsync)vf).GetModifiedDateUTCAsync() : DateTime.MinValue); e.RequestCachingKey = ra.GenerateRequestCachingKey(modDate); var settings = new ResizeSettings(ra.RewrittenInstructions); e.RewrittenQuerystring = settings; e.EstimatedContentType = ra.EstimatedContentType; e.EstimatedFileExtension = ra.EstimatedFileExtension; //A delegate for accessing the source file e.OpenSourceStreamAsync = async delegate() { return((vf != null) ? await vf.OpenAsync() : File.Open(ra.RewrittenMappedPath, FileMode.Open, FileAccess.Read, FileShare.Read)); }; //Add delegate for writing the data stream e.CreateAndWriteResultAsync = async delegate(System.IO.Stream stream, IAsyncResponsePlan plan) { //This runs on a cache miss or cache invalid. This delegate is preventing from running in more //than one thread at a time for the specified cache key try { if (!ra.ProcessingIndicated) { //Just duplicate the data using (Stream source = await e.OpenSourceStreamAsync()) await source.CopyToAsync(stream); //4KiB buffer } else { MemoryStream inBuffer = null; using (var sourceStream = vf != null ? await vf.OpenAsync() : File.Open(ra.RewrittenMappedPath, FileMode.Open, FileAccess.Read, FileShare.Read)) { inBuffer = new MemoryStream(sourceStream.CanSeek ? (int)sourceStream.Length : 128 * 1024); await sourceStream.CopyToAsync(inBuffer); } inBuffer.Seek(0, SeekOrigin.Begin); var outBuffer = new MemoryStream(32 * 1024); //Handle I/O portions of work asynchronously. var j = new ImageJob { Instructions = new Instructions(settings), SourcePathData = vf != null ? vf.VirtualPath : ra.RewrittenVirtualPath, Dest = outBuffer, Source = inBuffer }; await conf.GetImageBuilder().BuildAsync(j, int.MaxValue, CancellationToken.None); outBuffer.Seek(0, SeekOrigin.Begin); await outBuffer.CopyToAsync(stream); } ra.FireJobSuccess(); //Catch not found exceptions } catch (System.IO.FileNotFoundException notFound) { if (notFound.Message.Contains(" assembly ")) { throw; //If an assembly is missing, it should be a 500, not a 404 } //This will be called later, if at all. ra.FireMissing(); throw new ImageMissingException("The specified resource could not be located", "File not found", notFound); } catch (System.IO.DirectoryNotFoundException notFound) { ra.FireMissing(); throw new ImageMissingException("The specified resource could not be located", "File not found", notFound); } catch (Exception ex) { ra.FireJobException(ex); throw; } }; //All bad from here down.... context.Items[conf.ResponseArgsKey] = e; //store in context items //Fire events (for client-side caching plugins) conf.FirePreHandleImageAsync(this, context, e); //Pass the rest of the work off to the caching module. It will handle rewriting/redirecting and everything. //We handle request headers based on what is found in context.Items IAsyncTyrantCache cache = conf.GetAsyncCacheFor(context, e); //Verify we have a caching system if (cache == null) { throw new ImageProcessingException("Image Resizer: No async caching plugin was found for the request"); } await cache.ProcessAsync(context, e); }