Passing variable to another CGI.pm program

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

Hi all, I am having a heck of a time trying to figure out how to pass a variable from index.cgi to sum.cgi. I have an online form that displays each student from /etc/passwd on the school server. I can pass "Last Month" and "This Month" but I am not sure how to pass the student name to the other file. Any help would be greatly appreciated

#!/usr/bin/perl

use strict;
use warnings;
use CGI qw/:standard/;
use CGI::Carp qw/fatalsToBrowser/;

my $count = 3;
my $line;
my @list;

my $ifile = "/etc/passwd";
my %user;
my %name;
my $key;
open(my $IN, "<", $ifile);
while(<$IN>)
{
    chomp;
    my @data = split(/:/);
    
    $user{$data[0]} = $data[2];
    my @tmp = split(/,/, $data[4]);
    $name{$data[0]} = $tmp[0];
    
    }
close($IN);


print header(), start_html( -title=>'Account Summary');
print<<EOHTML;
    <!DOCTYPE html>
        <head>
         <title>Account Summary</title>
        </head>
         <body>
            <h1>Account Summary Gateway</h1>
            <p>Select which month(s)you would like to summarize:
            <form action="sum.cgi" method="get">
                <input type="checkbox" name="ThisMonth" value="current
+">This Month</br>
                <input type="checkbox" name="LastMonth" value="last">L
+ast Month
                <p>Select one of the $count accounts to summarize:</p>
                <select name="$key" size="15" multiple="multiple">
EOHTML
                    foreach my $key(sort keys %user)
                    {
                        if($user{$key} > 1001)
                        {
                            print"<option value=\"$key\">$key \($name{
+\"$key\"}\)</option><br />";
                            #print "$key $name{$key}\n";
                        }
                    }
                print<<EOHTML;
                    
            </select></br>
            <input type ="submit" name="sbutton" value="Go!">
            </form>
            </body>
EOHTML
[download]

Comment on Passing variable to another CGI.pm program Download Code

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Re: Passing variable to another CGI.pm program by greengaroo (Hermit) on Nov 27, 2012 at 15:38 UTC
It has been a while since I've done that but I think when you put the "multiple" option on a select box, you will receive an array of values on the other side. Try a print Dumper of the CGI params and you should be able to find the selected value(s). I think you would be able to do this: `my @names = $cgi->param('name_of_select_box');` If $cgi is a CGI object. But try the Dumper first to make sure. Testing never proves the absence of faults, it only shows their presence. -- greengaroo	[reply] [d/l]
Re: Passing variable to another CGI.pm program by blue_cowdawg (Monsignor) on Nov 27, 2012 at 16:24 UTC
Why pass the name? Use the UID that you are going to glean from /etc/password. Better yet why not just put the functionality of both CGI scripts into one CGI? This method is a good example of a justification to create modules. Update: I'm not a big fan of "pipe-fitting" processes together. I remember inheriting a project that suffered from performance issues what consisted of scriptA --pipe--> scriptB --pipe--> scriptC --> and nausuem and back to scriptA types of chains. First thing I did was create modules with the working "guts" of all the scripts and replaced all the scripts. Now if scriptA needed some functionality in scriptB it could access that functionality locally rather than piping. Peter L. Berghold -- Unix Professional Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg	[reply]
Re: Passing variable to another CGI.pm program by golux (Chaplain) on Nov 27, 2012 at 17:28 UTC
Hi deathmetalscottie, Make sure that you have a name defined for the <select> tag. In your code,you're using "$key", which you never define: `my $key; ... <select name="$key" size="15" multiple="multiple">` [download] So if you fix that, for example, calling it "multi": `my $name = "multi"; # Renamed from $key to be less confusing # Sorry, I don't want to show my /etc/password :) my %user = ( 'fred' => 101, 'barney' => 102, 'wilma' => 103, 'betty' => 104, 'pebbles' => 105, 'bambam' => 106, ); ... <select name="$name" size="15" multiple="multiple"> foreach my $key(sort keys %user) { my $val = $user{$key}; if ($val > 100) { print qq{<option value="$key">$key ($val)</option><br />}; } }` [download] Then you can see with a quick test which names were chosen, in sum.cgi, like this: `#!/usr/bin/perl use strict; use warnings; use CGI qw/:standard/; use CGI::Carp qw/fatalsToBrowser/; use Data::Dumper; my @users = param('multi'); die sprintf "Users selected: %s\n", Dumper(\@users);` [download] For example, selecting the 2 values "bambam (106)" and "pebbles (105)": `* bambam (106) barney (102) betty (104) fred (101) * pebbles (105) *** wilma (103)` [download] and clicking "Go!" to call sum.cgi should show: `Software error: Users selected: $VAR1 = [ 'betty', 'wilma' ];` [download] say substr+lc crypt(qw $i3 SI$),4,5	[reply] [d/l] [select]
Re: Passing variable to another CGI.pm program by deathmetalscottie (Initiate) on Nov 27, 2012 at 19:56 UTC
I actually figured this out and it was something rather small. In the line of code: `<select name="$key" size="15" multiple="multiple">` I replaced $key for just the name who `<select name="who" size="15" multiple="multiple">` That actually worked as I was able to pass over the variable. Although yes this would have been easier with one index.cgi file, this was a homework assignment so obviously my teacher is going to make us jump through hoops on the assignment and then go over best practice in class. Thanks guys.	[reply] [d/l] [select]