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

i wrote a rather shabby public links page a while ago which stayed on my win2k box for a while working perfectly, then when decided to upload it to a server it stops on the following line:

my (%params) = $query->Vars;

with no errors or anything. it just stops any ideas why, oh monks of great wisdom?

here's the full code
#!/usr/local/bin/perl -w
print "Content-type: text/html\n\n";

my $filename = "/home/user/cgi-bin/database.txt";

use CGI;
#use strict;
my ($query) = new CGI;
my $cgi_path = $query->script_name;
$cgi_path =~ s/(^.*\\)//;

my (%params) = $query->Vars;

my ($command) = $params{'command'};
touch() if ($command eq "touch");
addlink() if ($command eq "add");
unless (open FILE, $filename) { nofile(); }
 my @slurp = <FILE>;
close (FILE);

print<<END;
<html>
<head>
<title>Links</title>
</head>
<body>
<H1>Links Page</H1><hr><p>
<form method=POST action="$cgi_path">
Sorry, adding links is not working at the moment. Can anyone tell me w
+hy \%params = \$query->Vars; causes the script to stop?<br>
<table>
<tr><h3>Add Link</h3></tr><br>
<input type="hidden" name="command" value="add">
<tr><td>Name</td><td><input type="text" name="name" size="40"></td></t
+r>
<tr><td>Url</td><td><input type="text" name="url" size="40"></td></tr>
<tr><td></td><td><input type="submit" value="Submit"></td></tr>
</table>
</form>
<hr>
END

my $flag=0; my ($label, $i, @group, $line, $labeltmp);
foreach $line (@slurp) {
 if ($line =~ m/(\#label)(\s+)(.*)/g) {
  $labeltmp=$3;
  if ($flag == 1) {
   print "<h2>".$label."</h2><p>\n<ul>\n";
   @group = sort (@group);
   foreach (@group) {
    if (m/(.+)(\s+)(\S+$)/g) {
    print "<li><a href=\"$3\">$1</a><br>\n";
    }
   }
   print "</ul><hr>";
   undef(@group);
  }
  $i=0;
  $label=$labeltmp;
  $flag=1;
 } else {
 $i++;
 $group[$i]=$line;
 }
}
print "<h2>".$label."</h2><p>\n<ul>\n";
@group = sort (@group);
foreach (@group) {
 if (m/(.+)(\s+)(\S+$)/g){
  print "<li><a href=\"$3\">$1</a><br>\n";
 }
}
print "</ul><hr>";

print<<END;
</body>
</html>
END
exit;

sub nofile {
print<<END;
<html><head><title>Fatal Error!</title></head><body>
Can't read \'$filename\'<br>
<a href="$cgi_path?command=touch">Click here to create it</a>
</body></html>
END
exit(0);
}

sub touch {
unless (open FILE, ">$filename") { errorpage("Help! Can't touch file")
+; }
print FILE "#label Computers\n";
print FILE "site url\n";
close (FILE);
}

sub addlink {
unless (open FILE, ">>$filename") { errorpage("Help! Can't open databa
+se for appending"); }
errorpage("You must fill in both fields!") if (($params{'name'} eq "")
+ || ($params{'url'} eq ""));
print FILE $params{'name'}." ".$params{'url'}."\n";
close (FILE);
print<<END;
<a href="$cgi_path">Return</a>
END
exit;
}

sub errorpage {
print "<html><head><title>Fatal Error!</title></head><body>\n";
print @_;
print "</body></html>";
exit(0);
}

[download]

Replies are listed 'Best First'.
Re: a quick stab at a public links page
by CharlesClarkson (Curate) on Jul 20, 2001 at 08:36 UTC

    How do you know it stops at line 12? Is there an error? What is happening that makes you certain it is this line?

    Try adding use CGI::Carp 'fatalsToBrowser'; and run the program through a browser. Is there a error now? Let us know.

    BTW, what operating system is the server running? I assume it's not win2k.


    HTH,
    Charles K. Clarkson
[reply]
[d/l]
      i was putting print "m00"; before and after each line until i worked out where it was stopping :) then i tried taking the line out. (with other tweaks so i could)
      ill just trundle off to find out what its running, ive seen it somewhere around the site...
      ok, here's what it says:
      Portland web servers are based around IBM AIX and IBM RS/6000 web servers.

      ok, ive added the fatalsToBrowser line (assumed it was in already, which is why i was getting *really* confused!) and get the following:

      Software error:

      Undefined subroutine CGI::Vars

      For help, please send mail to the webmaster (support@portland.co.uk), giving this error message and the time and date of the error.

      im still not really much enlightened, surely use CGI; should be sorting that?

      hope you can help!

[reply]
[d/l]

           While not certain, I suspect the server may have an older version of CGI.pm installed. Perhaps a fellow monk knows when Vars was added to CGI.pm. If you can get a look at the CGI.pm source on your server, search for the Vars subroutine. You should be able to determine the version of CGI by printing $CGI::VERSION. Install the newest version from CPAN if you can. Try a Super Search on Vars

        If all else fails you could bother the author, but wait a few days for a reply here first.


        HTH,
        Charles K. Clarkson
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Re: a quick stab at a public links page
by CharlesClarkson (Curate) on Jul 22, 2001 at 20:35 UTC

    I took a closer look at your script and you don't need CGI::Vars at all. You may want to read the documentation on CGI.pm. Your missing a lot of oppurtunities. Here are few corrections that may have you up and going quickly.

    On this line we're creating %params.
    my (%params) = $query->Vars;

    CGI.pm has a function for this: param. To access any parameter, just call param('any'). To use it as a function we need to change use CGI; to use CGI qw/param/;

    Now that we can access param directly, let's make a few changes.

    my ($command) = $params{'command'};
touch() if ($command eq "touch");
addlink() if ($command eq "add");

    [download]
    becomes: 
    touch()   if param('command') eq 'touch';
addlink() if param('command') eq 'add';

    [download]
    ---------
    errorpage("You must fill in both fields!") if (($params{'name'} eq "")
              || ($params{'url'} eq ""));

    [download]
    becomes: 
    errorpage('You must fill in both fields!')
    if param('name') eq '' || param('url') eq '';

    [download]
    ---------
    print FILE $params{'name'}." ".$params{'url'}."\n";becomes: print FILE param('name'), ' ', param('url'), "\n";
    HTH,
    Charles K. Clarkson
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