IE6-8 unable to download file from HTTPS site

Question

I have an MVC .Net application that has actions that return report files, usually .xslx:

byte[] data = GetReport();
return File(data, 
    \"applica         


        

Answer 1

I was having a similar approach in that I had a BaseController class

[OutputCache(Duration=0)]
public class BaseController : Controller
{
    //snip snip: some utility stuff and shared endpoints among all my controllers
}

That caused the above mentioned problems in IE8. Applying the [IENoCacheAttribute] as shown above didn't work however. The problem is that the instruction filterContext.HttpContext.Response.ClearHeaders() removes all of my headers including eventual Content-Disposition headers etc... causing the file download to not happen correctly.

My approach was therefore to overwrite the default OutputCacheAttribute.cs in such a way that in case of IE it didn't apply any kind of caching headers, especially the problematic no-cache ones.

public class EnhancedOutputCacheAttribute : OutputCacheAttribute
{

    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {

        if (!IsFileResultAndOldIE(filterContext))
            base.OnActionExecuted(filterContext);
        else
        {
            //try the best to avoid any kind of caching
            filterContext.HttpContext.Response.Cache.SetCacheability(HttpCacheability.Private);
            filterContext.HttpContext.Response.Cache.SetMaxAge(new TimeSpan(0));
            filterContext.HttpContext.Response.Cache.SetExpires(DateTime.Now.AddMinutes(-5D));
        }
    }

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        if (!IsFileResultAndOldIE(filterContext))
            base.OnActionExecuting(filterContext);
    }

    public override void OnResultExecuted(ResultExecutedContext filterContext)
    {
        if (!IsFileResultAndOldIE(filterContext))
            base.OnResultExecuted(filterContext);
    }

    public override void OnResultExecuting(ResultExecutingContext filterContext)
    {
        if (!IsFileResultAndOldIE(filterContext))
            base.OnResultExecuting(filterContext);
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="filterContext"></param>
    /// <returns><c>true</c> for FileResults and if the browser is < IE9</returns>
    private bool IsFileResultAndOldIE(dynamic filterContext)
    {
        return filterContext.Result is FileResult &&
               filterContext.HttpContext.Request.IsSecureConnection &&
               string.Equals(filterContext.HttpContext.Request.Browser.Browser, "IE", StringComparison.OrdinalIgnoreCase) &&
               filterContext.HttpContext.Request.Browser.MajorVersion < 9;
    }

}

Here's the corresponding gist: https://gist.github.com/4633225

Answer 2

I've come up with a workaround, but it's a definite hack - this is a new cache attribute to replace the built-in [OutputCache] one:

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = false)]
public sealed class IENoCacheAttribute : ActionFilterAttribute
{
    public override void OnResultExecuting(ResultExecutingContext filterContext)
    {
        if (filterContext.HttpContext.Request.IsSecureConnection &&
            string.Equals(filterContext.HttpContext.Request.Browser.Browser, "IE", StringComparison.OrdinalIgnoreCase) &&
            filterContext.HttpContext.Request.Browser.MajorVersion < 9)
        {
            filterContext.HttpContext.Response.ClearHeaders();
            filterContext.HttpContext.Response.AddHeader("cache-control", "no-store, no-cache, must-revalidate");
        }
        else
        {
            filterContext.HttpContext.Response.Cache.SetNoStore();
            filterContext.HttpContext.Response.Cache.SetCacheability(HttpCacheability.NoCache);
            filterContext.HttpContext.Response.Cache.SetRevalidation(HttpCacheRevalidation.AllCaches);
        }

        base.OnResultExecuting(filterContext);
    }
}

It's a workaround at best though - what I really want is to extend the existing [OutputCache] and Response.Cache structures so that they have the desired output suitable for legacy IEs.