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a quick stab at a public links page

by Anonymous Monk
on Jul 20, 2001 at 07:51 UTC ( #98316=perlquestion: print w/ replies, xml ) Need Help??
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); }

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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
      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!

           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
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 ($command eq "add");
    becomes:
    touch() if param('command') eq 'touch'; addlink() if param('command') eq 'add';
    ---------
    errorpage("You must fill in both fields!") if (($params{'name'} eq "") || ($params{'url'} eq ""));
    becomes:
    errorpage('You must fill in both fields!') if param('name') eq '' || param('url') eq '';
    ---------
    print FILE $params{'name'}." ".$params{'url'}."\n";
    becomes: print FILE param('name'), ' ', param('url'), "\n";

    HTH,
    Charles K. Clarkson

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