Greetings, restletfarians, I am building a collection of web services that can be viewed as working together to create a hierarchy of abstractions (err, resources) over a large set of "atomic" raw data. Thus, the lowest level service provides a bunch of resources (atomic data) to a higher level service, which builds resources (abstractions of that raw data) for the next higher service, which builds its own resources (higher level abstractions) and so forth.
Since the "raw" data is quite fine-grained, it is quite important that the higher level abstraction services be able to cache the data obtained from lower level services. (Each of the raw data instances is a "resource" with its own URI, and a single intermediate abstraction will often require processing several thousand lower level resource instances.) Making life interesting is the fact that new raw data is arriving all the time which must percolate up the hierarchy. I think I pretty much understand how to deal with the "server" side of the cache problem. I can implement, for example, conditional GET in my server to avoid regenerating and resending the resource to the client, or (even better in my case) cache-control so that the server can indicate to the client that the provided resource representation will not change for a given period of time and to just reuse this one without making an HTTP request to the server. What I don't understand is how a Restlet client is supposed to physically cache the responses returned from a server. It would appear to me that shrinkwrapped support for this could be provided within the Restlet Framework. For example, if the cache-control indicates that the response from a GET request won't expire for an hour, one would think that that the Restlet Client class, after flipping a few switches and specifying a directory, could handle caching in a manner completely transparent to the application. My sense is that this is on the ToDo list for Restlet. So, my questions are: (1) Does my analysis above make sense? (2) What is the likelihood that shrinkwrapped support for client-side caching will be available in Restlet in the near future? (3) Since I need this pretty soon, what advice do people have about the best way to hand-roll my own client-side caching? Are there open source packages that can simplify the implementation? Any issues I should be aware of? Thanks very much for your help! Cheers, Philip
