How can I add the result of an ASP.NET MVC controller action to a Bundle?

Question

I have a controller action that returns Javascript file. I can reference this file from my view and it works fine. I\'d like to put it in a System.Web.Optimization.Bundle with t

Answer 1

Here is what I did for this scenario. I defined a "Bundle Result" and then in my Controller method, just returned a Bundle by name. I am using ETags (If-None-Match Header) as an optimization for client caching.

eg:

public ActionResult ReturnFooBundle()
{
    return new BundleResult("foo", TimeSpan.FromDays(7));
}

Here is the BundleResult implementation:

public class BundleResult
    : ActionResult
{
    private class BundleInfo
    {
        public string BundleETag;
        public DateTime LastModified;
        public Bundle TheBundle;
        public BundleResponse Response;
    }

    private static Dictionary _bundleCache = new Dictionary();

    public string BundleName { get; private set; }
    public TimeSpan CacheExpiry { get; private set; }

    public BundleResult(string bundleName, TimeSpan cacheExpiry)
    {
        BundleName = bundleName;
        CacheExpiry = cacheExpiry;
    }
    public override void ExecuteResult(ControllerContext context)
    {
        context.HttpContext.Response.Clear();
        BundleInfo bundleInfo = GetBundle(context.HttpContext);

        string requestETag = context.HttpContext.Request.Headers["If-None-Match"];
        if (!string.IsNullOrEmpty(requestETag) && (requestETag == bundleInfo.BundleETag))
        {
            context.HttpContext.Response.StatusCode = (int)HttpStatusCode.NotModified;
            context.HttpContext.Response.StatusDescription = "Not Modified";
            return;
        }
        else
        {
            BundleResponse bundleResponse = bundleInfo.Response;
            HttpResponseBase response = context.HttpContext.Response;
            response.Write(bundleResponse.Content);
            response.ContentType = bundleResponse.ContentType;

            HttpCachePolicyBase cache = response.Cache;
            cache.SetCacheability(HttpCacheability.ServerAndPrivate);
            cache.SetLastModified(bundleInfo.LastModified);
            cache.SetETag(bundleInfo.BundleETag);
        }
    }

    private BundleInfo GetBundle(HttpContextBase context)
    {
        // lookup the BundleResponse
        BundleInfo retVal;
        lock (_bundleCache)
        {
            _bundleCache.TryGetValue(BundleName, out retVal);
        }
        if(retVal != null)
        {
#if DEBUG
            // see if the contents have been modified.
            BundleContext bundleContext = new BundleContext(context, BundleTable.Bundles, BundleName);
            DateTime lastModified = retVal.TheBundle.EnumerateFiles(bundleContext).Select(fi => fi.LastWriteTimeUtc).Max();
            if (lastModified > retVal.LastModified)
            {
                // regenerate the bundleInfo
                retVal = null;
            }
#endif
        }
        if (retVal == null)
        {
            string rawBundleName = BundleTable.Bundles.ResolveBundleUrl(BundleName);
            string hash = rawBundleName.Substring(rawBundleName.IndexOf("?v=") + 3);
            Bundle bundle = BundleTable.Bundles.GetBundleFor(BundleName);
            BundleContext bundleContext = new BundleContext(context, BundleTable.Bundles, BundleName);
            BundleResponse bundleResponse = bundle.GenerateBundleResponse(bundleContext);
            DateTime lastModified = bundle.EnumerateFiles(bundleContext).Select(fi => fi.LastWriteTimeUtc).Max();
            retVal = new BundleInfo
            {
                BundleETag = hash,
                Response = bundleResponse,
                TheBundle = bundle,
                LastModified = lastModified,
            };
            lock (_bundleCache)
            {
                _bundleCache[BundleName] = retVal;
            }
        }
        return retVal;
    }
}