Howto include Perl Script into CGI script

monkfan has asked for the wisdom of the Perl Monks concerning the following question:

Most revered monks,

I have the following cgi script, it can also be viewed in browsable form here.
What it does is simply compute the total price of the order.

#!/usr/bin/perl -w
use CGI ':standard';

print header, start_html('Order Ice Cream with Price'), 
         h1('Order Ice Cream with Price');

generate_form();         
print_results() if param();
print end_html();

sub print_results {
    my @top = param('toppings'); 
    print b('Customer name: '), param('customer'), br, 
    "You ordered  ",
        param('no_unit'), ' unit of  ', param('cone'), ' cone.';
    print br;

    # how to include the perl script "compute_price.pl" result here?
    print ('Total price is ...'); 
}

sub generate_form {
    print hr, start_form,     
        strong('Your name : '),   
              textfield( -name => 'customer' ), br,br 
  
        strong('Cone: '),
            radio_group( -name     => 'cone', -multiple => 1,
                           -values   => [qw/sugar waffle/]),br,br 
        strong('Number of Units: '),
              textfield( -name => 'no_unit'), br,br
        submit( -value => 'Send Order' ), 
        end_form, hr;
}
[download]

Now I have a perl script that does the computation. Typically it is executed in command line like this.

$ perl  compute_price.pl -type sugar -unit 3
[download]

The perl script can be found below:

#!/usr/bin/perl -w
use strict;              
use Data::Dumper;        
use Carp;
use Getopt::Long;

my $cone_type = 'sugar';
my $no_unit   =  1;
my $help = 0;


if ( @ARGV == 0 ) {
    &usage();
    exit(1);
}
        
my $res = GetOptions ( "type=s"=>\$cone_type,
                       "unit=i"=>\$no_unit,      
                       "help"=>\$help,);         

if ($res) {

    die "Unit too large\n" if ($no_unit > 5);

    my %unitprice   = ( 'sugar' => 100, 'waffle' => 200 );
    my $total_price = $unitprice{$cone_type} * $no_unit;
    print "$total_price\n";   
}


sub usage {
    print <<HELP;
    
    Usage: perl $0 [-options] 
    
    -h         Print this help
    -type      Cone type
    -unit      No of Unit
HELP
     exit;
}
[download]

My questions are:

How can I include "compute_price.pl" into the main cgi script above, so that it prints the total price?
How can I also show the "die" version into the cgi-script when parameter given is incorrect. Just like in "compute_price.pl" ?

Regards,
Edward

Comment on Howto include Perl Script into CGI script Select or Download Code

Replies are listed 'Best First'.
Re: Howto include Perl Script into CGI script by BerntB (Deacon) on May 17, 2006 at 09:17 UTC
Sniff, sniff... the smell of ... homework? :-) Ah well, I'll give you some hints. You could make the second file into a module. (Read up on "package" and "use" it from your cgi file.) Implement it as a subroutine. You must put the previous shell-script (now module) in the Perl include path, as seen in the @INC array. To give an error message, check the return code of your new subroutine and show another html page. (You could also run the Perl script by using back-quotes, shell-script style.) Update: Added detail. Since the asking monk is much more experienced than me, I feel nervous about answering. But if he want to troll me more, I'll be happy to add more details. :-)	[reply]
Re^2: Howto include Perl Script into CGI script by monkfan (Curate) on May 17, 2006 at 09:37 UTC
(You could also run the Perl script by using back-quotes, shell-script style.) Hi BerntB, Thanks for your answer. Can you be a bit specific? Example? Here is what I have at the moment: sub print_results { my @top = param('toppings'); print b('Customer name: '), param('customer'), br, "You ordered ", param('no_unit'), ' unit of ', param('cone'), ' cone.'; print br; my $value = `perl compute_price.pl -type param('cone') -unit param +('no_unit')`; # Still doesn't show the value. What did I do wrong?? print 'Total price is', $value; } [download] But it doesn't show the price as you try see from the link I have above. Is there anything I did wrong? It seem to me CGI script has different property with Perl script. Maybe backquote is not for it? Regards, Edward	[reply] [d/l]
Re^3: Howto include Perl Script into CGI script by BerntB (Deacon) on May 17, 2006 at 09:45 UTC
The "param('no_unit')" parts (inside the backquotes) are evaluated as shell script. Set them to variables and have the variables inside the "`". Update: Please note the dangers of "injecting" stuff like shell commands into your backquotes-eval if you use data that comes from the CGI! Use taint and/or the system() call with multiple parameters. (I.e. do `system("perl", $param1, $param2);`)	[reply] [d/l]
Re^4: Howto include Perl Script into CGI script by monkfan (Curate) on May 17, 2006 at 13:28 UTC
Re^5: Howto include Perl Script into CGI script by wfsp (Abbot) on May 17, 2006 at 14:15 UTC
Some notes below your chosen depth have not been shown here
Re: Howto include Perl Script into CGI script by blazar (Canon) on May 17, 2006 at 09:41 UTC
How can I include "compute_price.pl" into the main cgi script above, so that it prints the total price? Usual answer: just make `compute_price.pl` into a module and use it from you cgi script, and possibly from a simplified cli version. How can I also show the "die" version into the cgi-script when parameter given is incorrect. Just like in "compute_price.pl" ? Just have a sub or method return, say, undef and have the main program display an error page if so.	[reply] [d/l]