Perl CGI redirect

jbt424 has asked for the wisdom of the Perl Monks concerning the following question:

I need to create a Perl CGI script that will accept a single parameter as input. The parameter will be a fully qualified URL and the script will redirect the browser to the URL that has been passed as the parameter. The method is a GET and not a POST.

The browser address bar will accept the full script with the URL parameter like this: http://webserver/cgi-bin/myscript.pl?URL=http://www.google.com I am new to Perl. I stole this code but it does not do a GET and I think I am using a bad example or one that does not apply to what I need to do: I resolved my issue and code is below.

#!/usr/local/bin/perl
use strict;
use warnings;


use CGI qw(:standard);
use CGI::Carp qw(warningsToBrowser fatalsToBrowser);
use DBI;
use URI::Escape;
use strictures;
use CGI;
use URI;

my $q = new CGI ;
my $url = "httpcandy";
 
# Process an HTTP request
#my @values  = $q->multi_param('form_field');
my $value   = $q->param('param_name');


print "Content-type: text/html\n\n";
#print "<pre>\n";
#
#foreach my $key (sort keys(%ENV)) {
#  print "$key = $ENV{$key}<br/>";
#}
#print "</pre>\n";



my $requested = URI->new( CGI::url() );
$requested->query( $ENV{QUERY_STRING} || $ENV{REDIRECT_QUERY_STRING} )
    if url_param();


#print header(),
#    start_html(),
#    h1("requested:"),
#    blockquote($requested),
#    h1("url:"),
#    blockquote($value),
#    h1("nothing else"),
#
#    end_html();
#    
if ($value =~ /http/)
{
   print "<META HTTP-EQUIV=refresh CONTENT=\"1;$value\">\n";
}
else
{
   print "<META HTTP-EQUIV=refresh CONTENT=\"1;URL=http://$value\">\n"
+;
};

exit;
[download]

Comment on Perl CGI redirect Download Code

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Re: Perl CGI redirect by FreeBeerReekingMonk (Deacon) on May 26, 2015 at 14:53 UTC
The variables you give after the ? are usually send as %ENV variables. Why not try to print them all and see if your webserver is like that? `#!/usr/local/bin/perl print "Content-type: text/html\n\n"; print "<pre>\n"; foreach $key (sort keys(%ENV)) { print "$key = $ENV{$key}<br/>"; } print "</pre>\n";` [download] Now, you seem to want to use CGI, in that case, you get them in param, and you can iterate over them, as described in this previous post: Best way to parse CGI params You can then use: `my $q = new CGI; if ($q->param("URL")) { ... }` [download] There is also something called Tainted mode, which you should use once your testcode is working, because what If the string after the ? is 2Mb big? or an invalid url etc.	[reply] [d/l] [select]
Re^2: Perl CGI redirect by Anonymous Monk on May 26, 2015 at 15:12 UTC
The variables you give after the ? are usually send as %ENV variables. Why not try to print them all and see if your webserver is like that? Trying to parse the query parameters out of %ENV vars yourself is an "ancient" method of doing things, which should no longer be recommended. The OP is already using CGI, which is a much better way of getting the parameters. There is also something called Tainted mode, which you should use once your testcode is working, because what If the string after the ? is 2Mb big? or an invalid url etc. Using taint mode is generally a good idea but it won't directly help with the two examples you mention. See perlsec.	[reply]
Re^2: Perl CGI redirect by jbt424 (Initiate) on May 26, 2015 at 16:32 UTC
FreeBeer, I will owe you a 12 pack. I will seriously ship it. I am not sure I understand completely, I was able to print out all the variables in your suggested code, but what is the intent? REQUEST_METHOD = GET And..if I take your code, what am I supposed to substitute? Remember that the URL needs to by dynamic so that I can enter any web address in the browser web address. `my $q = new CGI; if ($q->param("URL")) {....}` [download] How do I call my .pl script in the browser to call on the URL I am requesting? Is it like this? `http://webserver/cgi-bin/myscript.pl?URL=http://www.google.com` [download]	[reply] [d/l] [select]
Re^3: Perl CGI redirect by FreeBeerReekingMonk (Deacon) on May 28, 2015 at 21:15 UTC
Sorry for the delay, I was afk. Ah, yes. Let me present you with working code. Go to chapter 3-6 of `http://www.cgi101.com/learn/ch3/text.html` You would call it like `http://www.cgi101.com/book/ch3/get.cgi?firstname=hello&lastname=world` and you can read it like my `$var1 = param("firstname"); $var2 = param("lastname")` Source for both the webpage and the perl CGI and a working example are on that tutorial page. For more information just peruse: CGI Programming	[reply] [d/l] [select]
Re^4: Perl CGI redirect by FreeBeerReekingMonk (Deacon) on May 28, 2015 at 21:54 UTC