John Foderaro <jkf <at> franz.com> writes:

> >> Ok, that's Araneida in a nutshell.  Next up?  Someone want to
> >> tackle paserve or cl-modlisp?

I'm in the middle of building a new scheme based webserver called HIPY
(Hipy Isn't Patchy Yet). It comes out of experience of building a Java
based servlet container for the GNU project and from my wish list
from building webapps over the last 10 years.

HIPY maps a heirarchially defined, regular expression based namespace
to scheme handler procs. The namespace is defined in an XML file and
converted to an s-expression at startup.

The unusual part is that the handler procs are passed the regexp
match data when they are called. This is a lot more expressive and
powerful than the ordinary CGI path-match + path-info data passed to
handlers.

HIPY relies on scheme environments. The XML configuration file must
include an INIT element which specifies a scheme file to load or the
text of a scheme program. This scheme must create the bindings which
will be availble to map.

Thus a config file looks like this:

<?xml version="1.0"?>
<hipy-config>
  <init>
    (define with-connection 
      (make-db-con-pool "db" "user" "pass"))

    (define (blog-xml . entry)
      (with-connection ...))

    (define (blog-list path-match method headers in out)
      (if (not (eq? method 'GET))
          (throw 'http-method-not-supported))
      (let ((rss (blog-xml)))
          (http-respond out 200 "application/xml+rss")
          (send out (xslt-exec rss "some.xslt"))))

    (define (blog-entry path-match method headers in out)
      (let ((rss (blog-xml (match:substring path-match 1))))
          (http-respond out 200 "text/html")
          (send out (xst-exec rss "rss-to-html.xslt"))))
  </init>

  <host name="www.tapsellferrier.co.uk">

    <mapping location="/blog" handler="blog-list" >
      <mapping location="/\([0-9]+\)" handler="blog-entry"/>
    </mapping>

  </host>

</hipy-config>

Create a two level namespace where you can ask the server for URLs
like this:

   /blog       invokes blog-list handler
   /blog/1     invokes blog-entry handler
   /blog/2     invokes blog-entry handler

HIPY is threaded as per the Stevens recommendations for servers: the
accept is in the thread and thread blocking is used to select the
next acceptor.

It's all done using Guile right now, quite a bit might end up
implemented in C.

It's a bit of fun really but I though you all might be interested.

-- 
Nic Ferrier http://www.tapsellferrier.co.uk