First, you'll need a few prerequisites.
- the latest libopkele from http://kin.klever.net/libopkele (C++ implementation of important OpenID functions)
- libsqlite from http://www.sqlite.org (SQLite C libs)
to see additional options that can be specified.
make su root make install
Make sure that the file /tmp/mod_auth_openid.db is owned by the user running Apache. You can do this by (assuming www-data is the user running apache):
su root touch /tmp/mod_auth_openid.db chown www-data /tmp/mod_auth_openid.db
Or you can specify an alternate location that the user running apache has write privieges on (see the docs for the AuthOpenIDDBLocation directive on the homepage).
In either a Directory, Location, or File directive in httpd.conf, place the following directive:
AuthType OpenID Require valid-user
There are also additional, optional directives. See the homepage for a list and docs.
The user's identity URL will be available in the REMOTE_USER cgi environment variable after authentication.
See the project page for more information.