I've just finished a project that was developed using JavaServer Pages,
Servlets, and Struts.  I wanted to do this project in Ruby, but I was
overruled.  Now I'm about to start another Web application project for
which I've been given the go ahead to use Ruby to try to prove its worth
to others in my organization.

One of the reasons that I wasn't able to use Ruby on the previous project
is that I could not find a Web application framework that provided nearly
as much as the JSP/Servlets/Struts combination that we used for the Java
project.  I'm wondering if this state of affairs has improved at all.  I
searched on the RubyGarden wiki for some information, and although I found
some good discussions for improvement of the CGI library as well as some
talk of frameworks built on top of it, I didn't see anything that led me
to believe that any action has been taken towards these things.

Specifically, what I'm looking for is a Ruby Webapp framework that:

    * Provides separation of content and presentation, preferrably
following the MVC model

    * Works on all or most popular Web servers

    * Allows request URLs to be mapped to arbitrary Ruby code via some
configuration file or naming convention

    * Has good support for sessions

    * Supports a template-based approach, through which I could combine
several files together to render a view

Other features that would be nice to have are good error handling support,
support for unit testing, and some equivalent of JSP custom tags.

In short, I'm looking for the Ruby equivalent of JSP/Servlet/Struts.

I understand that there may not be a single package that provides all of
these features, but I'm hoping someone here can recommend a combination of
solutions that works well for the type of Web development implied by the
above.

I'm also willing to contribute to the development of any packages that are
working towards providing something like I've described.

Thanks for your help.

-- 
Jason Voegele
"We believe that we invent symbols. The truth is that they invent us."
    -- Gene Wolfe, The Book of the New Sun