WebApi 2.2 IIS 7.5 something is setting max-age - asp.net-web-api

Question

I have a .Net 4.5.2 WebApi 2.2 REST service. Windows 7 machine running IIS 7.5. It doesn't do much but return the current date/time. When hosted in IIS, I get response headers that look like this:
HTTP/1.1 200 OK
Cache-Control: max-age=60
Content-Length: 58
Content-Type: application/json; charset=utf-8
ETag: "c664145c-6923-44b6-b3fb-ff7e50259b44"
Server: Microsoft-IIS/7.5
ApplicationDate: Test with date 4/3/2015 3:18:08 PM
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Fri, 03 Apr 2015 19:18:10 GMT
{"messages":[],"result":"All is well 4/3/2015 3:18:07 PM"}
If I call it a second time, I see this:
HTTP/1.1 200 OK
Cache-Control: max-age=60
Content-Length: 58
Content-Type: application/json
ETag: "c664145c-6923-44b6-b3fb-ff7e50259b44"
Server: Microsoft-IIS/7.5
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Fri, 03 Apr 2015 19:27:25 GMT
{"messages":[],"result":"All is well 4/3/2015 3:18:07 PM"}
My custom header (ApplicationDate) is gone, and the time hasn't changed. The key is probably the Cache-Control: max-age=60 in there. I don't know where it's coming from!
If I run it "Self Hosted", same code...I see this:
HTTP/1.1 200 OK
Content-Length: 58
Content-Type: application/json; charset=utf-8
Server: Microsoft-HTTPAPI/2.0
ApplicationDate: Test with date 4/3/2015 3:35:31 PM
Date: Fri, 03 Apr 2015 19:35:31 GMT
{"messages":[],"result":"All is well 4/3/2015 3:35:30 PM"}
Something in the IIS pipeline is setting max-age. (BTW, testing with SoapUI and Fiddler, no browser issues to complicate things)
I have tried disabling the IIS OutputCache module. I verified using FailedReqLogFiles:
OUTPUT_CACHE_LOOKUP_END
Result 4
Result CACHING_DISABLED
When I change the cache-control headers in code, I see the changes in the Self-Hosted version, but something overwrites the headers in the IIS version back to max-age=60.
HTTP/1.1 200 OK
Cache-Control: max-age=60
Pragma: no-cache
Content-Length: 58
Content-Type: application/json; charset=utf-8
ETag: "3ce2e8b6-4891-496e-8bb7-087590239d6b"
Server: Microsoft-IIS/7.5
ApplicationDate: Test with date 4/3/2015 3:49:19 PM
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Fri, 03 Apr 2015 19:49:19 GMT
{"messages":[],"result":"All is well 4/3/2015 3:49:19 PM"}
Here's the controller:
/// <summary>
/// Get "REST" status
/// </summary>
/// <returns></returns>
[ActionName("GetStatusDate")]
[Route("GetStatusDate")]
public HttpResponseMessage GetStatusDate()
{
CommonResponse<string> response = new CommonResponse<string>();
response.Result = "All is well " + DateTime.Now;
HttpResponseMessage responseMessage = Request.CreateResponse(HttpStatusCode.OK, response);
responseMessage.Headers.Add("ApplicationDate", "Test with date " + DateTime.Now);
responseMessage.Headers.Remove("Cache-Control");
responseMessage.Headers.CacheControl = new CacheControlHeaderValue()
{
MaxAge = TimeSpan.FromSeconds(11),
NoCache = true,
Private = true
};
responseMessage.Headers.Add("Pragma","no-cache");
return responseMessage;
}
What is setting max-age?
Thanks,
Sean

Answer 1

So, I should have waited another hour before posting the question....turns out the problem was that the CacheOutputAttribute (OutputCache.V2) was not only set on specific resources, but had been added to the global filter collection. Since it inherits from FilterAttribute, IActionFilter, it worked fine as a global filter. That is why all calls were getting cached. It took ripping the project down to nothing to find the issue.
Sean