Caching in Wicket

[Peter Ertl <pe...@gmx.org>]

Hello Wicket Team,

I recently did quite a few changes on the way wicket handles caching (as you commit-readers probably already realized :-)

There were a few issues like:

- Public caches will not cache resource which they better should (like .CSS and .JS referred to from wicket:link), mostly because [Cache-Control: public] was missing
- Therefore utilization of CDN (content delivery networks) should be very hard (however I must admit I still have to gain more understanding on how CDN's work in general)
- Resource are not invalidated in the cache when they change in the application
- Responses should always send a [Date] header, especially when using [Last-Modified] or [Expires]
- Firefox does not cache resources on SSL even if they should (like CSS and JS)
- Caches like nginx cached http status = 302 server-side redirects (which is just sick :-)
- Redundant cache directives could eventually harm caching
- ....

I tried not to alter to much from wicket 1.4's behavior and soon will come up with a summary of the changes, not to mention the migration guide.

Please let me know if you discover something you don't like or think should be done differently.

Thanks
Peter