Question

I have a method I am calling via AJAX form my MVC3 application. The method creates an image using the WebImage helper. After the image is created, I then return a Json result from the controller. What is actually returned looks like image data. The content type I am sendingin the headers for the request is json, so I am not sure why the server is return the image data rather than my actual json result. If I remove the WebImage code, I get the actual json result I am looking for.

Method example:

[HttpPost]
public ActionResult CreateTempImage(AvatarUploadModel avatar){

try{

var imageId = Guid.NewGuid();
            var newFileName = imageId + "_" + Path.GetFileName(avatar.FileName);
            var imageTempPath = Server.MapPath("~/Areas/Admin/TemporaryUploads/" + newFileName);
            var image = new WebImage(avatar.FileName).Resize(400, 400, true).Write();
            image.Save(imageTempPath);
return Json(new { success = true }, JsonRequestBehavior.AllowGet);
}
catch(Exception ex){
              return Json(new { success = false}, JsonRequestBehavior.AllowGet);
                   }
}

Answer 1

This code is your problem

var image = new WebImage(avatar.FileName).Resize(400, 400, true).Write();

It’s documented as…

/// <summary>
/// Renders an image to the browser.
/// </summary>
/// 
/// <returns>
/// The image.
/// </returns>
/// <param name="requestedFormat">(Optional) The file format to use when the image is written.    </param>

Decompiling it gives the following code:

  requestedFormat = requestedFormat ?? this._initialFormat.ToString();
  byte[] bytes = this.GetBytes(requestedFormat);
  string str = !requestedFormat.StartsWith("image/", StringComparison.OrdinalIgnoreCase) ? "image/" + requestedFormat : requestedFormat;
  HttpResponse response = HttpContext.Current.Response;
  response.ContentType = str;
  response.BinaryWrite(bytes);
  return this;

i.e. it’s writing the image directly to HttpContext.Current.Response and setting the ContentType to the image’s format.

If you just want to save the image to the file system on the server then you can remove the call to Write and replace it with the call to Save:

var image = new WebImage(avatar.FileName).Resize(400, 400, true).Save(imageTempPath);

Cheers,
Dean