Caching http handler .ashx output

Question

Im creating an image which has some text in it, for every customer, the image contains their name and I use the Graphics.DrawString function to create this on the fly, however I

Answer 1

The simplest solution I can think of would be to just cache the Bitmap object in the HttpContext.Cache after you've created it in the image handler.

private Bitmap GetContactImage(int contactId, HttpContext context)
{
    string cacheKey = "ContactImage#" + contactId;
    Bitmap bmp = context.Cache[cacheKey];

    if (bmp == null)
    {
         // generate your bmp
         context.Cache[cacheKey] = bmp;
    }

    return bmp;
}

Answer 2

David,

you can use output caching on handler. not declaratively but in code behind. see if you can use following snippet.

TimeSpan refresh = new TimeSpan(0, 0, 15);
HttpContext.Current.Response.Cache.SetExpires(DateTime.Now.Add(refresh));
HttpContext.Current.Response.Cache.SetMaxAge(refresh);
HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.Server);
HttpContext.Current.Response.Cache.SetValidUntilExpires(true);

//try out with – a simple handler which returns the current time

HttpContext.Current.Response.ContentType = "text/plain";
HttpContext.Current.Response.Write("Hello World " + DateTime.Now.ToString("HH:mm:ss"));