.aspx page Response.BinaryWrite image on IE7

Question

I maintain an application that has a .aspx page that loads on image from the database and uses Response.BinaryWrite() to write it back to the client. This worked perfectly not long ago. Two things have changed, we upgraded the application to .NET 3.5 and they upgraded all the computers at work to IE7.

Everything works fine on Firefox, but all I get in IE7 is a red X. So I assume this issue is related to IE7? Is there a security setting somewhere that would stop it from loading images from a .aspx form? It's already set to display based on the content type and not the extension.

Here is some of the code. Like I said, I just maintain this app and didn't write it. I know using Session is not a great way of doing it, but it's what I have and the switch statement is just a "wtf?".

<asp:image id="imgContent" runat="server" Visible="true" ImageUrl="ProductContentFormImage.aspx"></asp:image>

    protected void Page_Load(object sender, System.EventArgs e)
    {
        Hashtable hshContentBinary = (Hashtable)Session["hshContentBinary"];
        byte[] content = (byte[]) hshContentBinary["content"];
        string extension = (string) hshContentBinary["extension"];


        string contentTypePrefix = "application";
        switch(extension.ToLower())
        {
            case "gif":
            case "jpg":
            case "bmp":
                contentTypePrefix = "image";
                break;
            case "tif":
                contentTypePrefix = "image";
                break;
            case "tiff":
                contentTypePrefix = "image";
                break;
            case "eps":
                contentTypePrefix = "image";
                break;
            default:
                Response.AppendHeader( 
                    "Content-disposition",
                    "attachment; filename=content." + extension );
                break;
        }
        Response.ContentType = contentTypePrefix + "/" + extension;
        Response.BinaryWrite(content);
    }

EDIT:

OK, I followed your suggestions and through a little more research I have changed the method to the following, but it still doesn't work.

protected void Page_Load(object sender, System.EventArgs e)
{
    Hashtable hshContentBinary = (Hashtable)Session["hshContentBinary"];
    byte[] content = (byte[]) hshContentBinary["content"];
    string extension = (string) hshContentBinary["extension"];
    string contentType;
    string contentDisposition = "inline; filename=content." + extension;

    Response.ClearContent();
    Response.ClearHeaders();
    Response.Clear();

    switch(extension.ToLower())
    {
        case "gif":
            contentType = "image/gif";
            break;
        case "jpg":
        case "jpe":
        case "jpeg":
            contentType = "image/jpeg";
            break;
        case "bmp":
            contentType = "image/bmp";
            break;
        case "tif":
        case "tiff":
            contentType = "image/tiff";
            break;
        case "eps":
            contentType = "application/postscript";
            break;
        default:
            contentDisposition = "attachment; filename=content." + extension;
            contentType = "application/" + extension.ToLower();
            break;
    }

    Response.Buffer = true;
    Response.Expires = 0;
    Response.ContentType = contentType;
    Response.AddHeader("Content-Length", content.Length.ToString());
    Response.AddHeader("Content-disposition", contentDisposition);
    Response.Cache.SetCacheability(HttpCacheability.NoCache);
    Response.BinaryWrite(content);
    Response.End();
}

Solution 1

The image was corrupted in a way that IE7 could not display it, but Firefox could. The image was large it wouldn't fit on the screen and I didn't see where it was cut off.

Thanks for all your suggestions.

Solution 2

Your mime types are not correct. This works better, at least for the images:

string contentType = "application/" + extension.ToLower();
switch(extension.ToLower()) {
   case "gif": contentType = "image/gif"; break;
   case "jpg":
   case "jpeg":
   case "jpe": contentType = "image/jpeg"; break;
   case "bmp": contentType = "image/bmp"; break;
   case "tif":
   case "tiff": contentType = "image/tiff"; break;
   case "eps": contentType = "application/postscript"; break;
   default:
      Response.AppendHeader( 
         "Content-disposition",
         "attachment; filename=content." + extension );
      break;
}
Response.ContentType = contentType;

Hera are mime types and file extensions, if you need to add more: http://www.w3schools.com/media/media_mimeref.asp

Solution 3

I can tell you that this way of image loading works fine in IE7 (just had written same sorta code some time back). So, there could be following issues: 1) Try doing a Response.Clear() before setting the ContentyType and do a response.end in the end. 2) Make sure that your extension in the session is without the period (.) i.e. it should be just gif for .gifs, jpg for .jpg etc.

S

Solution 4

Consider setting up your page with some caching including client side cache control headers. When you do this make sure that you set a different filename for each individual image

contentDisposition = String.Format("attachment; filename=content{0).{1}",fileName, fileExtension);

and the client side cache headers

context.Response.Cache.SetMaxAge(TimeSpan.FromSeconds(YourDatabaseImageOrConfigFile.CacheSeconds));
context.Response.Cache.SetOmitVaryStar(true);
context.Response.Cache.SetLastModified(YourDatabaseImage.ModifiedDate);

I would make this page into an ASHX http handler as well to get rid of the overhead of the page lifecycle.

I have this whole thing written a few times over and can provide the code if needed. This image endpoint is on a site doing around 80 requests a second.

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