URLCache

URLCache is a sample iPhone application that demonstrates how to download a resource off the web, store it in the application's data directory, and use the local copy of the resource. URLCache also demonstrates how to implement a couple of caching policies:

- The local copy of a web resource should remain valid for a period of time (for example, one day) during which the web is not re-checked.

- The HTTP header's Last-Modified date should be used to determine the last time a web resource changed before re-downloading it.

The audience for this sample is iPhone developers using resources such as images that are retrieved or updated from the web.