/// <summary>
/// Enables processing of HTTP Web requests by a custom HttpHandler that implements the <see cref="T:System.Web.IHttpHandler"/> interface.
/// </summary>
/// <param name="context">An <see cref="T:System.Web.HttpContext"/> object that provides references to the intrinsic server objects (for example, Request, Response, Session, and Server) used to service HTTP requests.</param>
public void ProcessRequest(HttpContext context)
{
context.Response.Clear();
context.Response.Cache.SetCacheability(HttpCacheability.Public);
context.Response.Cache.SetAllowResponseInBrowserHistory(true);
context.Response.Cache.SetValidUntilExpires(true);
context.Response.BufferOutput = false;
try {
HttpRequest request = context.Request;
HttpResponse response = context.Response;
bool leechProtect = request.GetQueryStringValue <bool>("lp", false);
//validate the request
if (!request.IsValid(true, leechProtect))
{
throw new HttpException((int)HttpStatusCode.BadRequest, "The request did not pass validation.");
}
//retrieve the filepath of the image we would like to retrieve
string imageSrc = GetImageSourceQueryStringValue(context);
//create an image retriever and get the file extension
ImageRetriever imageRetriever = ImageRetrieverFactory.CreateImageRetriever(imageSrc);
string filename = imageRetriever.GetFileNameWithoutExtension();
string extension = imageRetriever.GetExtension().ToUpperInvariant();
//set the content type of the response
response.ContentType = GetContentType(extension);
//set the content-disposition header to the given SaveName or the filename
string saveName = request.GetQueryStringValue <string>("sn", filename);
response.AppendHeader("Content-Disposition", string.Concat("inline; filename=\"", saveName, "\""));
using (MemoryStream memoryStream = new MemoryStream()) {
string hash = request.GetQueryStringValue <string>("ha", null);
bool cacheOutput = request.GetQueryStringValue <bool>("co", false);
bool fromCache = false;
if (cacheOutput)
{
object cache = context.Cache[hash];
if (cache != null)
{
fromCache = true;
byte[] buffer = (byte[])cache;
memoryStream.Write(buffer, 0, buffer.Length);
}
}
if (!fromCache)
{
int width = request.GetQueryStringValue <int>("w", 0);
int height = request.GetQueryStringValue <int>("h", 0);
GraphicsQuality graphicsQuality = (GraphicsQuality)request.GetQueryStringValue <int>("rq", 2);
bool maintainPalette = request.GetQueryStringValue <bool>("mp", false);
bool clip = request.GetQueryStringValue <bool>("cl", false);
using (Image originalImage = imageRetriever.GetImage())
using (Image resizedBitmap = (clip) ? originalImage.Clip(width, height, graphicsQuality, maintainPalette)
: originalImage.Resize(width, height, graphicsQuality, maintainPalette)) {
if (!resizedBitmap.HasIndexedPixelFormat())
{
string copyrightText = request.GetQueryStringValue <string>("ct", null);
if (!string.IsNullOrEmpty(copyrightText))
{
int copyrightFontSize = request.GetQueryStringValue <int>("cts", 0);
resizedBitmap.AddCopyrightText(copyrightText, copyrightFontSize);
}
if (request.GetQueryStringValue("g", false))
{
resizedBitmap.ApplyGrayscaleColorMatrix();
}
if (request.GetQueryStringValue("n", false))
{
resizedBitmap.ApplyNegativeColorMatrix();
}
if (request.GetQueryStringValue("s", false))
{
resizedBitmap.ApplySepiaColorMatrix();
}
float brightness = request.GetQueryStringValue <float>("b", 0F);
if (brightness != 0)
{
resizedBitmap.SetBrightness(brightness);
}
float contrast = request.GetQueryStringValue <float>("c", 0F);
if (contrast != 0)
{
resizedBitmap.SetContrast(contrast);
}
}
ImageFormat imageFormat = GetImageFormatByExtension(extension);
long outputQuality = request.GetQueryStringValue <long>("oq", 75L);
if (QuantizeableExtension(extension) && request.GetQueryStringValue <bool>("q", false))
{
using (Image quantizedBitmap = resizedBitmap.OctreeQuantize()) {
quantizedBitmap.SaveToMemoryStream(memoryStream, imageFormat, outputQuality);
}
}
else
{
resizedBitmap.SaveToMemoryStream(memoryStream, imageFormat, outputQuality);
}
}
}
memoryStream.Capacity = (int)memoryStream.Position;
if (memoryStream.Capacity > 0)
{
response.Cache.SetExpires(DateTime.Now.AddMinutes(browserCacheExpirationMinutes));
response.Cache.SetLastModified(imageRetriever.GetLastModifiedDate());
memoryStream.WriteTo(context.Response.OutputStream);
if (cacheOutput && !fromCache)
{
context.Cache[hash] = memoryStream.ToArray();
}
}
}
}
catch (FileNotFoundException) {
context.Response.StatusCode = (int)HttpStatusCode.NotFound;
}
catch (HttpException httpException) {
context.Response.StatusCode = httpException.GetHttpCode();
}
finally {
context.Response.Flush();
context.Response.End();
}
}
