I am rewriting a debugging module to be object-oriented. This module makes extensive use of CGI.pm's HTML tag generation capability. As a result, it instantiates a new CGI object when my object's new() constructor is called. Unfortunately, if the calling CGI program uses the POST method to receive data, my routine's instantiation of a new CGI object will cause the data in STDIN to be read. As a result, if they create my object before a new CGI object, they lose all of their POST data!

To get around this, I try to read $ENV{'CONTENT_LENGTH'} amount of data from STDIN if the POST method is used. If read any data, I kill the program telling the user that they need to instantiate a new CGI object before they instantiate a debugging object. Here's the code: 

sub new {
    my $class  = $_[0];
    my $buffer;

    if ( $ENV{'REQUEST_METHOD'} eq 'POST' ) {
        read (STDIN, $buffer, $ENV{'CONTENT_LENGTH'});
    }

    my $cgi = CGI->new();

    if ( length $buffer ) {
        print $cgi->header( "text/plain" ) .
              "Data was read from STDIN while using the POST method.\n
+" .
              "You must instantiate a new CGI::DebugVars object AFTER\
+n" .
              "instantiating a CGI object.";
        exit;
    }
    my $objref = { _active   => 1,
                   _border   => 1,
                   _continue => 0,
                   _cgi      => $cgi,
                   _pretty_not_installed => 0 };
    bless $objref, $class;
    return $objref;
}

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My problem is that it seems like a very ugly hack. I'm really not testing to see if a CGI object already exists, I'm inferring its existence from the presense of data available in STDIN. Is there a clean way to determine if the user has already instantiated a CGI object (short of searching through the packages for one)?

I'm also wondering if it's possible that other data may be available through STDIN in a CGI script? Since my routine reads that data, it will cause a problem for the end-user's code.

Cheers,
Ovid

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In reply to CGI object already instantiated? by Ovid

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