Simple http redirect is failing with Perl 5.8.9 and IIS6

[jbach]

We recently started a move of our web sites to Server 2003 from 2000 while upgrading Perl from 5.6 to 5.8. Most of our web sites use a simple perl script that redirects a web client to a login page. Under 5.6.1 we used:

use strict;
print "Location: ./cgi-bin/PromptEID.pl\n\n";
exit(0);

Using Perl 5.8 this fails, produces no output and never does the redirect.

we had to change the code to:

use strict;
use CGI;

my $q = CGI->new;
print $q->redirect ("./cgi-bin/promptEID.pl");
exit(0);

This works fine. We've been trying to find out what changed in Perlis.dll between 5.6.1 and 5.8.9 and I can't find a thing. Any help is appreciated.

[RonB]

You can find the change logs here: http://perldoc.perl.org/index-history.html

[RonB]

You should reread this portion of the CGI doc.

http://search.cpan.org/~lds/CGI.pm-3.49/lib/CGI.pm#GENERATING_A_REDIRECTION_HEADER

The key part is this:

You should always use full URLs (including the http: or ftp: part) in redirection requests. Relative URLs will not work correctly.

It might be better to say "Relative URLs will have unpredictable and unreliable results".

[jbach]

You can find the change logs here: http://perldoc.perl.org/index-history.html

We still don't have a definative answer why our redirect command ( print "Location: ./cgi-bin/nli.pl\n\n";) ran under 5.6 and failed under 5.8. A couple of our programmers didn't like loading the CGI module so came up with:

 print "Status: 302 Moved\n";
    print "Location: ./cgi-bin/nli.pl\n\n";

and it seems to have fixed the problem with redirection on the new web servers.
Actually, you only need a 3xx code after status - no text afterward is even required.

Simpler and less code.

[RonB]

Yes that will work, but it's recommended to use the full URL instead of the relative path when doing redirects. One reason being that if you're using a proxy server, that proxy server is allowed to alter the relative url path (adding its hostname). It also may forward the request to another proxy server and that server may/can alter relative urls.

What reasons do your programmers have for not wanting to load/use the CGI module? Is their objection the added overhead when the script is only doing a redirect and nothing more, or is their objection more broad?

[jbach]

Yes that will work, but it's recommended to use the full URL instead of the relative path when doing redirects. One reason being that if you're using a proxy server, that proxy server is allowed to alter the relative url path (adding its hostname). It also may forward the request to another proxy server and that server may/can alter relative urls.

What reasons do your programmers have for not wanting to load/use the CGI module? Is their objection the added overhead when the script is only doing a redirect and nothing more, or is their objection more broad?

Since CGI is a pretty big module and this redirect is on the home page of multiple web sites they were concerned about the overhead and performance penalties. BTW thanks your your replies.

[RonB]

For simple redirects and nothing more, then I'd agree that using the CGI module would be overkill.

But if you're doing more involved things, then IMO it's a must, especially for form processing.