Trac Installation on tools.ietf.org
===================================

Background
----------

The Track installation used on the tools.ietf.org site is different from the
installation examples provided with Trac and on http://trac.edgewall.com.  The
reason is mainly that the multi-project examples all assume that Trac
constitutes the whole of the deployed environment, rather than being part of a
greater set.  This means that the examples assume that accessing the
individual projects through URLs of the form "/$some_path/trac/$projname"
makes sense, while in our case, we would like the URLs to look like
"/$some_path/$projname/trac".  In the multi-project configuration, this would
make Trac always believe that the project name is 'trac' - the last path
component.

Explored Alternatives
---------------------

Make Apache set ``TRAC_ENV`` dynamically
........................................

Tell Apache to dynamically set Trac's environment variable ``TRAC_ENV`` to the
particular value for the accessed project:

``/etc/apache2/sites-available/tools.ietf.org``:

::

    ScriptAliasMatch "^/wg/[^/]+/trac(/.*)?" /usr/share/trac/cgi-bin/trac.cgi$1
    <LocationMatch "^/wg/([^/]+)/trac">
       SetEnv TRAC_ENV "/www/tools.ietf.org/tools/trac/wg/$1"
    </LocationMatch>

This doesn't work because Apache doesn't support $n replacements based on
earlier LocationMatch matches.

Use .htaccess with default ScriptAlias
......................................

Maybe we could use individual .htaccess files in each WG directory to set the
``TRAC_ENV`` variable to the required value?

``/etc/apache2/sites-available/tools.ietf.org``:

::

    ScriptAliasMatch "^/wg/[^/]+/trac(/.*)?" /usr/share/trac/cgi-bin/trac.cgi$1


``/www/tools.ietf.org/wg/examplewg/.htaccess``:

::

    SetEnv TRAC_ENV "/www/tools.ietf.org/wg/examplewg/trac"

This doesn't work because this .htaccess isn't read when ScriptAlias points to
another directory.


Use .htaccess with a local CGI script
.....................................

Suppose we let ScriptAlias point to a script which is placed so that the
.htaccess file actually gets read?

``/etc/apache2/sites-available/tools.ietf.org``:

::

    ScriptAliasMatch "^/wg/([^/]+)/trac(/.*)?" /www/tools.ietf.org/wg/$1/trac/index.cgi$2


``/www/tools.ietf.org/wg/examplewg/.htaccess``:

::

    SetEnv TRAC_ENV "/www/tools.ietf.org/wg/examplewg/trac"

This *does* work, but it is not easily adapted to a Fast-CGI solution.  It is
the set-up which is currently in use, but an alternative which will permit
fast-cgi usage would be preferred - the current solution is anything but
snappy...