/// <summary>
/// Post processes the image.
/// </summary>
/// <param name="context">The current context.</param>
/// <param name="stream">The source image stream.</param>
/// <param name="extension">The image extension.</param>
/// <returns>
/// The <see cref="MemoryStream" />.
/// </returns>
public static async Task <MemoryStream> PostProcessImageAsync(HttpContext context, MemoryStream stream, string extension)
{
if (!PostProcessorBootstrapper.Instance.IsInstalled)
{
return(stream);
}
string sourceFile = null, destinationFile = null;
var timeout = PostProcessorBootstrapper.Instance.Timout;
try
{
// Save source file length
var length = stream.Length;
// Create a temporary source file with the correct extension
var tempSourceFile = Path.GetTempFileName();
sourceFile = Path.ChangeExtension(tempSourceFile, extension);
File.Move(tempSourceFile, sourceFile);
// Give our destination file a unique name
destinationFile = sourceFile.Replace(extension, "-out" + extension);
// Get processes to start
var processStartInfos = GetProcessStartInfos(extension, length, sourceFile, destinationFile).ToList();
if (processStartInfos.Count > 0)
{
// Save the input stream to our source temp file for post processing
using (var fileStream = File.Create(sourceFile))
{
await stream.CopyToAsync(fileStream).ConfigureAwait(false);
}
// Create cancellation token with timeout
using (var cancellationTokenSource = new CancellationTokenSource(timeout))
{
foreach (var processStartInfo in processStartInfos)
{
// Use destination file as new source (if previous process created one).
if (File.Exists(destinationFile))
{
File.Copy(destinationFile, sourceFile, true);
}
// Set default properties
processStartInfo.FileName = Path.Combine(PostProcessorBootstrapper.Instance.WorkingPath, processStartInfo.FileName);
processStartInfo.CreateNoWindow = true;
processStartInfo.WindowStyle = ProcessWindowStyle.Hidden;
// Run process
using (var processResults = await ProcessEx.RunAsync(processStartInfo, cancellationTokenSource.Token).ConfigureAwait(false))
{
if (processResults.ExitCode == 1)
{
ImageProcessorBootstrapper.Instance.Logger.Log(typeof(PostProcessor), $"Unable to post process image for request {context.Request.Unvalidated.Url}, {processStartInfo.FileName} {processStartInfo.Arguments} exited with error code 1. Original image returned.");
break;
}
}
}
}
// Save result
if (!File.Exists(destinationFile))
{
File.Copy(sourceFile, destinationFile, true);
}
var result = new PostProcessingResultEventArgs(destinationFile, length);
if (result.ResultFileSize > 0 && result.Saving > 0)
{
using (var fileStream = File.OpenRead(destinationFile))
{
stream.SetLength(0);
await fileStream.CopyToAsync(stream).ConfigureAwait(false);
}
}
}
}
catch (OperationCanceledException)
{
ImageProcessorBootstrapper.Instance.Logger.Log(typeof(PostProcessor), $"Unable to post process image for request {context.Request.Unvalidated.Url} within {timeout}ms. Original image returned.");
}
catch (Exception ex)
{
// Some security policies don't allow execution of programs in this way
ImageProcessorBootstrapper.Instance.Logger.Log(typeof(PostProcessor), ex.Message);
}
finally
{
// Always cleanup files
try
{
// Ensure files exist, are not read only, and delete
if (sourceFile != null && File.Exists(sourceFile))
{
File.SetAttributes(sourceFile, FileAttributes.Normal);
File.Delete(sourceFile);
}
if (destinationFile != null && File.Exists(destinationFile))
{
File.SetAttributes(destinationFile, FileAttributes.Normal);
File.Delete(destinationFile);
}
}
catch
{
// Normally a no no, but logging would be excessive + temp files get cleaned up eventually.
}
}
// ALways return stream (even if it's not optimized)
stream.Position = 0;
return(stream);
}
