Caching not working right in my ASP.NET MVC website?

Question

Hi folks,

i'm trying to use OutputCaching in my ASP.NET MVC website. Problem is, when i try and change the value of one my querystring params, it's returning the data for the first item that was requested!

Here's my code (with the param names changed) ...

[ApiAuthorize]
[HandleErrorAsJson]
public class SearchController : Controller
{
    [AcceptVerbs(HttpVerbs.Get)]
    [OutputCache(Duration = 60, VaryByParam = "*")]
    public ActionResult ScoreCard(string foo, byte? bar, byte? pewpew)
    {
    ..
    }
}

• NOTE 1: ApiAuthorize - custom attribute that checks for a querystring param called 'Key' and checks an in memory dictionary, to see if it exists.
• NOTE 2: HandleErrorAsJson - custom attribute that returns the error message as json if an exception was/is thrown.

and here's two sample calls i'm making to this action :-

• /GET http://api.MySite.com/search/scorecard?foo=hello+world,+PewPew&key=abcd1234&bar=2
• /GET http://api.MySite.com/search/scorecard?foo=invalid+search+stuff&key=abcd1234&bar=2

so the data from the first call (foo = hello world, Pew Pew) is returned as a 200 OK. Then the second api call returns a 200 OK but with the data from the previous call.

Also, i'm not using any proxy server. If i comment out the OutputCache attribute, all is good.

I've also tried the following (manually listing each time i need to cache) .....

[OutputCache(Duration = 60, VaryByParam = "foo,key,bar,pewpew")]

No luck :(

Notice how i need to make sure that i include the API 'Key' parameter as part of the cache unique key. I don't want to people to search for the same thing, but if the second person doesn't have the right key, they shouldn't get a cached result, but an error message (techinically, it's a 401 Not Authorised, but anyways)...

Thoughts?

Answer 1

I use a filter for output caching which will give programmatic control for debugging and also will set when it needs to be. Feel free to use this and see if setting it here would make the difference which I think it might (also make sure any previous caching is cleared)

public class CacheFilterAttribute : ActionFilterAttribute
    {
        private const int Second = 1;
        private const int Minute = 60 * Second;
        private const int Hour = 60 * Minute;
        public const int SecondsInDay = Hour * 24;


        /// <summary>
        /// Gets or sets the cache duration in seconds. The default is 10 seconds.
        /// </summary>
        /// <value>The cache duration in seconds.</value>
        public int Duration
        {
            get;
            set;
        }

        public int DurationInDays
        {
            get { return Duration / SecondsInDay; }
            set { Duration = value * SecondsInDay; }
        }

        public CacheFilterAttribute()
        {
            Duration = 10;
        }

        public override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            if (Duration <= 0) return;

            HttpCachePolicyBase cache = filterContext.HttpContext.Response.Cache;
            TimeSpan cacheDuration = TimeSpan.FromSeconds(Duration);

            cache.SetCacheability(HttpCacheability.Public);
            cache.SetExpires(DateTime.Now.Add(cacheDuration));
            cache.SetMaxAge(cacheDuration);
            cache.AppendCacheExtension("must-revalidate, proxy-revalidate");
        }
    }

I'm just using this so far for a very static part of a site, so have a call like this

[CacheFilter(DurationInDays = 1)]

Obviously you'd just like to extend this to have VaryByParams exposed as a property, can provide but sounds like you'd know what to do.

Answer 2

The list of parameters in VaryByParam is supposed to be semicolon delimited, not comma delimited. Give that a try. That said, the * should have worked.