PHP does not see environmental variables pertaining to Shib but Perl does

[Peter Schober]

* Hough, Kenneth P <kenneth.phough at WPI.EDU> [2012-06-01 14:58]:
> >There's no information here to help you diagnose this.
> >Is the PHP file in a directory which either requires a shib session
> >or sees one once it's available? You know this how?
> 
> The PHP script sends a AuthnRequest to the IDP and after
> authentication, the IDP sends a response to the ACS and redirects to
> the profile page of the user.  There is no .htaccess explicitly
> requiring shib authentication because our app requires different
> login methods since not all of the institutions using our app has
> shib or similar authentication service.  After I do this
> authentication, I can run a CGI script to confirm REMOTE_USER and
> similar variables, and also I can confirm that a session has been
> made through Shibboleth.sso/Session.  I need a way for the PHP
> script to know that the user has authenticated successfully because
> I will be doing session management with PHP.

The specific resource you're trying to access (whatever it may be)
needs to be known by httpd to require authn. See "Passive Protection"
at https://wiki.shibboleth.net/confluence/display/SHIB2/NativeSPProtectContent
Usually this means setting something like
<Location /whatever>
AuthType shibboleth
Require shibboleth
</Location>
in your httpd config.
But I've asked plenty of questions designed to help you diagnose your
problem (e.g. specific log files), none of which you even mention.
-peter