I have an slightly one-off scenario for a site I'm working on.
I am routing certain request paths to a custom HTTP module that dynamically outputs "static" content. By that, I mean javascript and css content. However, that content is generated dynamically by the module, but once generated, does not change very often.
So, I would like to cache the output of my custom module, but for some reason, neither cached content, nor 304's are being returned to the client like I would expect.
If I browse to a URL using Firefox, the local browser caching seems to work. The browser uses what it has cached locally and doesn't make a request to the server.
However, if I press F5 on a page, the browser attempts to re-fetch the file from the server, and the server subsequently redirects to the module, regenerates the content, and essentially serves it fresh. I would expect IIS to instead return 304 to the client, or serve the content from the cache and avoid calling the module entirely.
The module seems to be returning correct cache headers:
http://www.mydomain.com/SpecialPath/File_17aa85bf3bf430066a0524787be6af7b9363c8ae.js
Cache-Control public, max-age=1800
Content-Encoding gzip
Content-Length 60568
Content-Type application/x-javascript; charset=utf-8
Date Tue, 27 Mar 2012 20:25:42 GMT
Etag 17aa85bf3bf430066a0524787be6af7b9363c8ae
Last-Modified Tue, 27 Mar 2012 20:25:43 GMT
Server Microsoft-IIS/7.5
Vary Accept-Encoding
X-AspNet-Version 4.0.30319
When I use F5 the browser request headers also seem to be OK:
Cache-Control max-age=0
If-Modified-Since Tue, 27 Mar 2012 20:25:21 GMT
If-None-Match 17aa85bf3bf430066a0524787be6af7b9363c8ae
However, if I set a break point, I see the request being passed through to the module.
304 is never returned, and neither is the content ever served from the output cache.
Do I need to do anything extra or special to get output caching to cache content returned from a custom module?
Is there something possibly wrong with my headers?
