Is there a reason why you are not using CGI and CGI::Cookie for this? If you are prone to CPAN modules, then please read this.

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

As I mentioned, I've been working on this one problem for days. I've tried to use CGI::Cookie, copying the example directly from the CPAN page. I didn't care what data I wrote to the cookie file file, as long as I wrote something. Here's the script I used:

#!/usr/bin/perl
####################################

use CGI qw/:standard/;
use CGI::Cookie;



sub write_cookie
    {

    my $c = new CGI::Cookie(-name => 'foo',
                    -value => ['bar','baz'],
                    -expires => '+3M'
                    );

    print header(-cookie=>[$c]);

    %cookies = fetch CGI::Cookie;
    $id = $cookies{'ID'}->value;

    %cookies = parse CGI::Cookie($ENV{COOKIE});

    }

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This is what displays on the screen:

Set-Cookie: foo=bar&baz; path=/; expires=Wed, 29-Sep-2004 19:22:16 GMT Date: Thu, 01 Jul 2004 19:22:16 GMT Content-Type: text/html; charset=ISO-8859-1

The rest of the page is blank. Since this was even worse that what I was getting before, I returned to work with my former code.

I also tried CGI, using an example I was able to find:

#!/usr/bin/perl
####################################


use CGI;
$cgiobject=new CGI;
$cgiobject->use_named_parameters;

&get_state_variables;
$cookie_data=&prepare_cookie;
&set_cookie($cookie_data);

return;

sub get_state_variables() #retrieve from the CGI queries the keys and 
+value we want to store in the cookie
    {
    $b_first=$cgiobject->param("reg_custnamef");
    $b_mid=$cgiobject->param("reg_custnamemi");
    $b_last=$cgiobject->param("reg_custnamel");
    }

sub prepare_cookie()     #packages the variables into one data string 
+for storage in cookie
    {
    $cookie_data="b_first=$b_first|".
             "b_mid=$b_mid|".
             "b_last=$b_last";
    return $cookie_data;
    }

sub set_cookie($cookie_data)         #sets cookie on user's machine
    {
    $final_cookie=$cgiobject->cookie(-name=>'searchform',
                         -value=>$cookie_data,
                         -expires=>'+6M');
    print $cgiobject->header(-cookie=>$final_cookie);
    } 


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but I couldn't get it to run. I tried using SYSTEM and then EXEC, neither of which I've ever tried using before, but to no avail.

Uh...try this?

common.cgi

#!/usr/bin/perl
####################################

use CGI qw/:standard/;
use CGI::Cookie;



sub write_cookie
    {

    my $c = new CGI::Cookie(-name => 'foo',
                    -value => ['bar','baz'],
                    -expires => '+3M'
                    );

    print header(-cookie=>[$c]);

    %cookies = fetch CGI::Cookie;

##  This is very bad. You should check that $cookies{'ID'} exists
##  or your script will die when you run this code.
#    $id = $cookies{'ID'}->value;

##  You've already filled %cookies with the cookies. Why
##  do it again?
#    %cookies = parse CGI::Cookie($ENV{COOKIE});

    }

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script.pl

#!/usr/bin/perl

require "common.cgi";

write_cookie();

print "Something";
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antirice    
The first rule of Perl club is - use Perl
The ith rule of Perl club is - follow rule i - 1 for i > 1

Also, your print statements with the cookies are missing \r\n at the end.

I've tried to use the modules, without success. My own ignorance is undoubtedly responsible. I'm still trying to learn Perl, after several years of writing scripts, and I haven't studied the modules.

I tried to limit the amount of information that I included in my original problem declaration because I know that much of it would be superfluous, but here's a little background.

The application is a shopping cart system. The main script, named kart.cgi, does contain a  content command line. Most of the output takes place in another script, called config.cgi. The latest script is called register.cgi, and contains no  print statements. All information is passed to config for output.

All of the subroutines for registration are in the register.cgi script, but control remains with kart.cgi. I thought that by using the  require command, the  content would be negated when the subroutines were accessed, but apparently not. :-)

Until the visitor inputs the information that I am trying to output with the cookie, how can I write it to his or her cookie file? Ergo, I need to collect the data before I can write it out. If I was simply creating a visit count, or something like that, I could write the cookie as soon as the kart.cgi is opened.

To the best of my knowledge, the \r\n at the end of a print statement is only important as a delimiter when viewing source code. Is there another reason why it should be in the  Set-cookie: command line?

I need to collect the data before I can write it out.

Yes, that is true. However, this means that the user will have to click a link that sends the information or submit a form that sends the information before you can set a cookie.

You need some logic in your script that can detect whether the user already has a cookie, has just submitted data that you can use to set a cookie, or has no cookie or cookie-making data. Only then can you solve this problem.

Also keep in mind that you cannot set a cookie and read its values in the same invocation. I think this is what's confusing you most right here. CGI programming is rather like a conversation between two very polite people who never interrupt and wait for a complete response before answering back.

As chromatic says, you need to display the form as one Web page, then submit it to a script that will output the cookie headers. That script will need to parse the information the user entered, then output the headers (including the cookie headers), then output the body of the Web page.

As for line endings in the headers, they are important, though whether you should use "\n" or "\r\n" may be Web server dependent (I usually use "\n", and assume my Web server will change it to a protocol-appropriate line ending). Line endings are how the Web server and browser know that one header has ended and the next has begun.

You need to understand how cookies and HTTP headers work. The headers contain the cookie and *should* look like:

HTTP/1.1 200 OK
Set-Cookie: blah
[other headers]
Content-Type: text/html
                           <-- Blank line ie \n\n after text/html term
+inates header
[Form Content Here]
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If you see the Cookie as plaintext you have outputted a valid \n\n terminated header *before* you have outputted the Set-Cookie Header. Unbuffer with $|++; at the top of the script, and check the output order. Go to http://web-sniffer.net/ and test your script to see what is being sent in what order. You are getting the order wrong.

As others have said, CGI and CGI::Cookie are perfect for this.

It sounds suspiciously like a buffered-output problem, where one module is buffering the output to be sent to STDOUT on completion of the script, and you're subverting the purity of the HTTP headers by issuing a print statement before it's time.

It also could be, as others have said, that you're not placing the "\r\n" after the cookie header.

Unless you're writing your own one-off modules to learn more about the CGI interface, in general, please, please, please use the various CGI modules; they're well tested and make writing secure CGI scripts if not simple, then at least attainable for a novice.