Outputcache 1 action, 2 views

Question

So I have the following action which I am trying to add output caching to:

[OutputCache(CacheProfile = OutputCacheProfileNames.Hours24)]
public ActionResult ContactUs()
{
  ContactUsModel model = _modelBuilder.BuildContactUsModel();

  if (Request.IsAjaxRequest())
  {
    return Json(StringFromPartial(partialTemplate, model), JsonRequestBehavior.AllowGet);
  }
  else
  {
    return View(model);
  }
}

But this seem to cache the first view that is requested - ie either the json OR the normal view.

Is there a way to get the output caching to work for both views, without having to split them out of the same action?

check out varyby http://blog.danielcorreia.net/asp-net-mvc-vary-by-current-user/ — REDEVI_, Mar 30 '16 at 11:44
@REDEVI_ unfortunately I can't use `VaryByParam` as no parameters are passed into the action, I'll have a read of that custom thing, but looks like it may be the way to go — Pete, Mar 30 '16 at 12:06

score 1 · Answer 1 · answered Mar 30 '16 at 12:58

Thanks to the comments by REDEVI_ for pointing me in the right direction, I have been able to solve this.

I changed my output caching to:

[OutputCache(CacheProfile = OutputCacheProfileNames.Hours24, VaryByCustom = "IsAjax")]

And then in my global.asax file, I added the following override:

    public override string GetVaryByCustomString(HttpContext context, string custom)
    {
        if (context != null)
        {
            switch (custom)
            {
                case "IsAjax":
                    return new HttpRequestWrapper(context.Request).IsAjaxRequest() ? "IsAjax" : "IsNotAjax";
            }
        }

        return base.GetVaryByCustomString(context, custom);
    }

Chris Pratt · Accepted Answer · 2016-03-30T13:27:19.373

You beat me to the punch in answering your own question, but I thought this code may still be helpful. Since varying by user is such a common scenario, you should probably account for being able to do that and your AJAX vary. This code will allow you vary on any number of custom parameters, by appending to a single string to vary on.

public override string GetVaryByCustomString(System.Web.HttpContext context, string custom)
{
    var args = custom.ToLower().Split(';');
    var sb = new StringBuilder();

    foreach (var arg in args)
    {
        switch (arg)
        {
            case "user":
                sb.Append(User.Identity.Name);
                break;
            case "ajax":
                if (context.Request.Headers["X-Requested-With"] != null)
                {
                    // "XMLHttpRequest" will be appended if it's an AJAX request
                    sb.Append(context.Request.Headers["X-Requested-With"]);
                }
                break;
            default:
                continue;
        }
    }

    return sb.ToString();
}

Then, you would just do something like the following if you need to vary by multiple custom params.

[OutputCache(CacheProfile = OutputCacheProfileNames.Hours24, VaryByCustom = "User;Ajax")]

Then, if you ever need additional custom vary params, you just keep adding case statements to cover those scenarios.

nice, didn't think about the multiple scenario case – Pete Mar 30 '16 at 13:59 — Pete, Mar 30 '16 at 13:59

Outputcache 1 action, 2 views

2 Answers2