title: URL query string convention for multiple sort
body: <p>I have a RESTful web application that supports multiple sort fields on a collection of items. Is there a common convention for encoding these sort fields into the query string of a URL? I'm considering a pattern like the following: </p>
  
  <pre><code>http://myapp.com/books?sort=author:asc,datepublished:desc&amp;count=12 
  </code></pre>
  
  <p>This would sort the collection of books by author and then by date published.</p>
  
  <p>Basically, I need a convenient way for the name-value pairs in my query string to have name-value pairs of their own. I'll need to do something similar to the above example for filter parameters, too.</p>
  
  <p>Does Rails or ASP.NET MVC have a pattern for this? Are there other frameworks that have established ways for dealing with this issue? I'd rather use a familiar format than roll my own.</p>
  
  <p>I'd also prefer a format that uses as little URL percent-encoding as possible. </p>