Prerequisites

• Ruby[ruby-lang.org] 1.6.7 or later. Earlier versions may work, but I haven't tested them.
• Apache[httpd.apache.org] 1.3 or later with mod_includes. You may be able to use other HTTP servers, but you'll need Apache if you want to use mod_ruby (see below).
• Berkeley DB[www.sleepycat.com] version 2 or later (for caching metadata), and bdb[moulon.inra.fr/ruby/bdb.html], the Ruby interface to Berkeley DB. (Optional, but strongly recommended).
• mod_ruby[modruby.net] 1.0.1 or later. Includes ERuby. (Optional).

Installation

1. Customize nav.rb:
   • Set DB_DIR to point to a directory where Nav can cache metadata. This directory must be writable by the user as which the web server runs.

     Alternately, you can set DB_DIR to nil at the expense of a performance penalty: no database cache will be kept.

   • If the root of your document hierarchy is not the same directory as the web server's "document root", set SITE_ROOT_URL to an absolute URL (without the "host" part) pointing to this directory. For example, if your document root is in /data/htdocs and your document hierarchy is in /data/htdocs/subsite/mysite, you would set SITE_ROOT_URL to "/subsite/mysite".

     This variable can be overridden on a page-by-page basis by setting an environment variable of the same name. See the Usage section of the README document.

   • Populate the BOGONODE hash.

     BOGONODE contains names for nodes with URLs that don't map onto a filesystem path: e.g., URLs mangled by the web server, URLs that point to CGI scripts or pages on other sites, etc. Instead of searching out metadata for these nodes, Nav simply returns a childless dummy node with the specified name.

2. Move nav.rb to a directory where ERuby documents (or ruby CGI scripts) can require it. Make sure the file is readable by the user as which the web server runs.
3. If you want to use CGI instead of (or in addition to) eRuby, put nav.cgi in a directory where the web server can run it. Modify the first two lines of the file: they should specify the location of your Ruby interpreter and the directory where nav.rb lives.