title: How to describe part of a sub-resource using RESTful Web Services?
body: <p>We are designing an application based on RESTful Web Services and Resource Oriented Architecture, as described in the o'Reilly book RESTful Web Services.</p>
  
  <p>We are also implementing client side caching.</p>
  
  <p>My question is - let's say you have a common subresource but you are modifying part of it.
  How do you represent that new modified resource so that you can cache it separately from the original resource and refer to the modification as such on the server.</p>
  
  <p>For example, our application is a financial modeling application.</p>
  
  <p>I might ask for financial data about IBM as:  </p>
  
  <pre><code>GET http://{servername}:{port}/[HOLTWS]/resources/factsheet/IBM/variables/{Variable-List-Id}
  </code></pre>
  
  <p>Ok, that returns the fundamental "factsheet" for IBM for the current fiscal year.</p>
  
  <p>But now, I want to change the model fiscal year to the prior year. I could make each year its own sub-resource but that seems too granular and would promote too much variation.</p>
  
  <p>Is there a good ROA way to do ask for a piece of a subresource and handle the client side caching with conditional GET without making each subset of the subresource a new subresource?</p>