Where's the filehandle in a PerlHandler module?

[Clayton Mitchell]

Sorry to ask such a newbie question, but I can't figure this out.

In a handler I want to process all requests and parse the document
requested and spit it out after marking it up.

I have put in place this code, but I don't see how to access the actual
requested document.

I'm hoping there's already an open filehandle to it somewhere?

######   a simple handler - but doesn't print the actual requested
document.
package _Parse;

sub handler {
          my $r = shift;
           my $symname;
          $r->content_type("text/html");
          $r->send_http_header;
          $r->print("header text\n");

   # this doesn't work ---
      while (<>) {
        $r->print;
        $_->print;
      }
      # this prints the environment variables
       foreach $key (keys %ENV) {
         print "$key: $ENV{$key}";
         print "<br>";
       }

      }
      1;