Caching

Recently I encountered a bug that only some users saw, and which did not reproduce locally on development environment. The setup was: An intranet page has an IFrame …that is dynamically changed to point to an attachment …which is served from MVC action returning FileContentResult This is a pretty common pattern to open files on browser without leaving the current page. And it worked like charm in all browsers, except on Internet Explorer 8 on testing environment, where IE just showed an error message that the address cannot be opened. IE 7 might be affected too, but I did not test on that. ...

I find myself searching for this information over and over again for each web site I develop, so I guess I must blog this topic to remember it from now on. IIS 7 has a very powerful caching framework, but some of the defaults are in my opinion not very well thought for modern web applications. For example: by default Javascript files are not compressed with GZIP, and cache location for static content is not public by default. So, if you use T4MVC, SquishtIt, or any other means to link to your static files with a timestamp then you might want to use settings along these lines: ...