URL $ENV variables

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

Hi,

If my url is http://www.perlmonks.com/index.pl?node=Seekers, I am trying to get my script name, i.e. index.pl.

I use $ENV{REQUEST_URI} to get the current url.

I have some params attached to the url which I access via $ENV{QUERY_STRING}.

So in order to get index.pl (as in the example above) I use the following:

  $attach1 = $ENV{REQUEST_URI};
  if($attach1 =~ /\\/){
    my @filename_parts = split /\\/,$attach1;
    my $length = scalar(@filename_parts);
    $attach1 = $filename_parts[--$length];
  }
  if($attach1 =~ /\//){
    my @filename_parts = split /\//,$attach1;
    my $length = scalar(@filename_parts);
    $attach1 = $filename_parts[--$length];
  }
[download]

The above gives me index.pl?node=Seekers, half way there.

To strip off ?node=Seekers I use the following:

  $paramstr = "\?".$ENV{QUERY_STRING};
  $attach1 =~ s/$paramstr/;
[download]

And that is where my code breaks. How do I strip off the query string so I am left with index.pl?

Comment on URL $ENV variables Select or Download Code

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Re: URL $ENV variables by sgifford (Prior) on Aug 04, 2003 at 08:43 UTC
I think you simply want: `$attach1 =~ s/\?.$//;` [download] But you seem to be doing this in an awfully complicated way, and your parsing code is fragile (it will fail on: http://www.perlmonks.com/index.pl?node=Smokers/Jokers , for example) Have you considered the URI module? Update*: I see why you'd want to use `$ENV{QUERY_STRING}`. The problem with your code is that the double-quotes are eating the backslash---by the time the regex sees the question mark it's unbackslashed, and so doesn't make any sense. Single quotes won't do that (at least not with a question mark). You're also missing the replacement string on your regex. This code works for me: `$paramstr = '\?'.$ENV{QUERY_STRING}; $attach1 =~ s/$paramstr//;` [download] But it fails if there are slashes in the query part of the string.	[reply] [d/l] [select]
Re: URL $ENV variables by antirice (Priest) on Aug 04, 2003 at 08:29 UTC
Check out $0. For more information, perldoc perlvar. antirice The first rule of Perl club is - use Perl The ith rule of Perl club is - follow rule i - 1 for i > 1	[reply]
Re: Re: URL $ENV variables by bodmin (Acolyte) on Aug 04, 2003 at 08:35 UTC
I tried that but couldn't figure it out. there is no reference as to which $ENV variables there are in perl.	[reply]
Re: Re: Re: URL $ENV variables by antirice (Priest) on Aug 04, 2003 at 08:45 UTC
Check out this script for what environment variables are set. It's nice for debugging, but don't keep it on your server. `#!/usr/bin/perl -w use CGI qw(header start_html end_html); print header(),start_html(); print "$_ = $ENV{$_}<br>" foreach (keys %ENV); print "\$0 is $0"; print end_html();` [download] Of course, you could just use CGI and use its url() or script_name() methods. For more on the syntax for the url() method, check out this link. antirice The first rule of Perl club is - use Perl The ith rule of Perl club is - follow rule i - 1 for i > 1	[reply] [d/l]
Re: Re: Re: Re: URL $ENV variables by sgifford (Prior) on Aug 04, 2003 at 09:36 UTC
Re: Re: Re: URL $ENV variables by Anonymous Monk on Aug 04, 2003 at 22:35 UTC
That's because $ENV is decided by the enviornment the script is running in. See antirice's post above this. Note that $ENV is different depending upon your server OS, and whatever else happens to be floating around on the system. Also note that there is a lot more stuff in $ENV when running a script on a webserver, then just running it on the command line. Printing all the keys in the enviornment you will use is basically the only way to be sure you know what's available.	[reply]
Re: URL $ENV variables by snowcrash (Friar) on Aug 04, 2003 at 08:38 UTC
Your code probably breaks because there's a syntax error in your substitution, you are missing on slash at the end. It should rather be `$attach1 =~ s/$paramstr//;` Anyway, I'd make use of the CGI modulue and its url() method. `use CGI; my $q = new CGI; my $url = $q->url(-absolute => 1);` [download] regards, snowcrash	[reply] [d/l] [select]
Re: URL $ENV variables by jsprat (Curate) on Aug 04, 2003 at 08:47 UTC
Is this is a standard CGI? If so, have a look at `$ENV{SCRIPT_FILENAME}` and `$ENV{SCRIPT_NAME}`. SCRIPT_FILENAME gives the absolute path to the running script and SCRIPT_NAME gives the virtual path to the script, both sans query string. If you want to see all environment variables available to your script, create a script that loops through all the keys of %ENV and prints all key/value pairs. HTH	[reply] [d/l] [select]
Re: URL $ENV variables by naChoZ (Curate) on Aug 04, 2003 at 12:54 UTC
You can do it with the URI module pretty easily: `#!/usr/local/bin/perl -w use strict; use URI; my $url = 'http://www.example.com/foo/bar.pl?baz'; my $u1 = URI->new($url); my @seg = $u1->path_segments; print "file: $seg[-1] \n";` [download] -- "I just read perlman:perlboot," said Tom, objectively. naChoZ	[reply] [d/l]
Re: URL $ENV variables by chanio (Priest) on Aug 05, 2003 at 02:00 UTC
RTFM (sorry :) http://sunsite.iisc.ernet.in/virlib/perl/example/ewtoc.html	[reply]


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