Can an ASP.NET MVC controller return an Image?

Question

Can I create a Controller that simply returns an image asset?

I would like to route this logic through a controller, whenever a URL such as the following is requeste

Answer 1

UPDATE: There are better options than my original answer. This works outside of MVC quite well but it's better to stick with the built-in methods of returning image content. See up-voted answers.

You certainly can. Try out these steps:

1. Load the image from disk in to a byte array
2. cache the image in the case you expect more requests for the image and don't want the disk I/O (my sample doesn't cache it below)
3. Change the mime type via the Response.ContentType
4. Response.BinaryWrite out the image byte array

Here's some sample code:

string pathToFile = @"C:\Documents and Settings\some_path.jpg";
byte[] imageData = File.ReadAllBytes(pathToFile);
Response.ContentType = "image/jpg";
Response.BinaryWrite(imageData);

Hope that helps!

Answer 2

Why not go simple and use the tilde ~ operator?

public FileResult TopBanner() {
  return File("~/Content/images/topbanner.png", "image/png");
}

Answer 3

if (!System.IO.File.Exists(filePath))
    return SomeHelper.EmptyImageResult(); // preventing JSON GET/POST exception
else
    return new FilePathResult(filePath, contentType);

SomeHelper.EmptyImageResult() should return FileResult with existing image (1x1 transparent, for example).

This is easiest way if you have files stored on local drive. If files are byte[] or stream - then use FileContentResult or FileStreamResult as Dylan suggested.

Answer 4

I also encountered similar requirement,

So in my case I make a request to Controller with the image folder path, which in return sends back a ImageResult object.

Following code snippet illustrate the work:

var src = string.Format("/GenericGrid.mvc/DocumentPreviewImageLink?fullpath={0}&routingId={1}&siteCode={2}", fullFilePath, metaInfo.RoutingId, da.SiteCode);

                if (enlarged)
                    result = "<a class='thumbnail' href='#thumb'>" +
                        "<img src='" + src + "' height='66px' border='0' />" +
                        "<span><img src='" + src + "' /></span>" +
                        "</a>";
                else
                    result = "<span><img src='" + src + "' height='150px' border='0' /></span>";

And in the Controller from the the image path I produce the image and return it back to the caller

try
{
  var file = new FileInfo(fullpath);
  if (!file.Exists)
     return string.Empty;


  var image = new WebImage(fullpath);
  return new ImageResult(new MemoryStream(image.GetBytes()), "image/jpg");


}
catch(Exception ex)
{
  return "File Error : "+ex.ToString();
}

Answer 5

you can use File to return a file like View, Content etc

 public ActionResult PrintDocInfo(string Attachment)
            {
                string test = Attachment;
                if (test != string.Empty || test != "" || test != null)
                {
                    string filename = Attachment.Split('\\').Last();
                    string filepath = Attachment;
                    byte[] filedata = System.IO.File.ReadAllBytes(Attachment);
                    string contentType = MimeMapping.GetMimeMapping(Attachment);

                    System.Net.Mime.ContentDisposition cd = new System.Net.Mime.ContentDisposition
                    {
                        FileName = filename,
                        Inline = true,
                    };

                    Response.AppendHeader("Content-Disposition", cd.ToString());

                    return File(filedata, contentType);          
                }
                else { return Content("<h3> Patient Clinical Document Not Uploaded</h3>"); }

            }

Answer 6

To expland on Dyland's response slightly:

Three classes implement the FileResult class:

System.Web.Mvc.FileResult
      System.Web.Mvc.FileContentResult
      System.Web.Mvc.FilePathResult
      System.Web.Mvc.FileStreamResult

They're all fairly self explanatory:

• For file path downloads where the file exists on disk, use FilePathResult - this is the easiest way and avoids you having to use Streams.
• For byte[] arrays (akin to Response.BinaryWrite), use FileContentResult.
• For byte[] arrays where you want the file to download (content-disposition: attachment), use FileStreamResult in a similar way to below, but with a MemoryStream and using GetBuffer().
• For Streams use FileStreamResult. It's called a FileStreamResult but it takes a Stream so I'd guess it works with a MemoryStream.

Below is an example of using the content-disposition technique (not tested):

    [AcceptVerbs(HttpVerbs.Post)]
    public ActionResult GetFile()
    {
        // No need to dispose the stream, MVC does it for you
        string path = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "App_Data", "myimage.png");
        FileStream stream = new FileStream(path, FileMode.Open);
        FileStreamResult result = new FileStreamResult(stream, "image/png");
        result.FileDownloadName = "image.png";
        return result;
    }