Why is output caching not working for my ASP.NET MVC 4 app?

Question

I am having an issue where output caching doesn't appear to be working for my ASP.NET MVC 4 (EPiServer 7) website.

I have the following output cache profile in my web.config:

<caching>
  <outputCacheSettings>
    <outputCacheProfiles>
      <add name="PageOutput" enabled="true" duration="300" varyByParam="*" location="ServerAndClient" />
    </outputCacheProfiles>
  </outputCacheSettings>
</caching>

And here is my output caching configuration for static resources:

<caching>
  <profiles>
    <add extension=".gif" policy="DontCache" kernelCachePolicy="CacheUntilChange" duration="0.00:01:00" location="Any" />
    <add extension=".png" policy="DontCache" kernelCachePolicy="CacheUntilChange" duration="0.00:01:00" location="Any" />
    <add extension=".js" policy="DontCache" kernelCachePolicy="CacheUntilChange" duration="0.00:01:00" location="Any" />
    <add extension=".css" policy="DontCache" kernelCachePolicy="CacheUntilChange" duration="00:01:00" location="Any" />
    <add extension=".jpg" policy="DontCache" kernelCachePolicy="CacheUntilChange" duration="0.00:01:00" location="Any" />
    <add extension=".jpeg" policy="DontCache" kernelCachePolicy="CacheUntilChange" duration="00:01:00" location="Any" />
  </profiles>
</caching>

And my controller is decorated with an output cache attribute like so:

[OutputCache(CacheProfile = "PageOutput")]
public class HomePageController : BasePageController<HomePage>
{ ...}

I'm watching the following counters in perfmon but not seeing them increment as expected when I visit the home page:

• \ASP.NET Apps v4.0.30319(__Total__)\Output Cache Entries
• \ASP.NET Apps v4.0.30319(__Total__)\Output Cache Hits

I've also been testing using tinyget like so:

tinyget -srv:mywebsite -uri:/ -threads:1 -loop:20

Any advice would be greatly appreciated!

Answer 1

So, it turns out that OutputCaching was working, it was just that my method of testing it was flawed. The result of an action will only be cached if the response doesn't include a cookie. Of course the first response always includes a cookie if you have ASP.NET Session enabled which we do. Therefore the first response headers look like this:

HTTP/1.1 200 OK
Cache-Control: private, max-age=600
Content-Type: text/html; charset=utf-8
Content-Encoding: gzip
Expires: Tue, 26 Nov 2013 03:48:44 GMT
Last-Modified: Tue, 26 Nov 2013 03:38:44 GMT
Vary: *
Set-Cookie: ASP.NET_SessionId=kbnhk4lphdlcpozcumpxilcd; path=/; HttpOnly
X-UA-Compatible: IE=Edge
Date: Tue, 26 Nov 2013 03:38:44 GMT
Content-Length: 9558

Assuming your browser or test tool can accept cookies and include those in the subsequent requests, the next request to the same page would result in HTTP response headers like so:

HTTP/1.1 200 OK
Cache-Control: private, max-age=598
Content-Type: text/html; charset=utf-8
Content-Encoding: gzip
Expires: Tue, 26 Nov 2013 03:48:45 GMT
Last-Modified: Tue, 26 Nov 2013 03:38:45 GMT
Vary: *
X-UA-Compatible: IE=Edge
Date: Tue, 26 Nov 2013 03:38:45 GMT
Content-Length: 9558

As there is no client specific information in the response the output can now be cached as expected.

So, lesson is when testing output caching use a testing tool that can accept and return cookies in subsequent requests.

We ended up using Jmeter rather than tinyget and everything now works as expected.