The Apache/Perl integration project brings together the
       full power of the Perl programming language and the Apache
       HTTP server.  This is achieved by linking the Perl runtime
       library into the server and providing an object oriented
       Perl interface to the server's C language API.  These
       pieces are seamlessly glued together by the mod_perl
       server plugin, making it is possible to write Apache
       modules entirely in Perl.  In addition, the persistent
       interpreter embedded in the server avoids the overhead of
       starting an external interpreter and the penalty of Perl
       start-up (compile) time.

       Without question, the most popular Apache/Perl module is
       Apache::Registry module.  This module emulates the CGI
       environment, allowing programmers to write scripts that
       run under CGI or mod_perl without change.  Existing CGI
       scripts may require some changes, simply because a CGI
       script has a very short lifetime of one HTTP request,
       allowing you to get away with "quick and dirty" scripting.
       Using mod_perl and Apache::Registry requires you to be
       more careful, but it also gives new meaning to the work
       "quick"!

       Although it may be all you need, a speedy CGI replacement
       is only a small part of this project. Callback hooks are
       in place for each stage of a request.  Apache-Perl modules
       may step in during the handler, header parser, uri
       translate, authentication, authorization, access, type
       check, fixup and logger stages of a request.