The internal service cache should support the HTTP standard cache-control

[hean01]

For now the internal service cache doesn't support HTTP cache-control functionality to provide cache information of object fetched to the client of the service. This is needed for proper caching of resources client side.

The main reason for the service cache functionality is that a client should not need to have internet access to be fully functional. The other reason is that the service have control of resource lifetimes regardless of what the original location reports to the client.

Speed and cache size is also a factor, we could fully rely on the client side cache but this cache is probably limited in size especially on android devices and not shared among several devices.

• The service cache is only intentionally to be used for static item metadata such as images, even thou they might not be static it's not a main problem to show an outdate images from the cached resource life time.