Upload the file:
##

my $filename = $this->cgi()->param('upload_file');
my $xml = _upload_file($filename);

sub _upload_file {
    my $filename = shift;

    my $file_contents = "";
    my $buffer;
    
    while ( read($filename, $buffer, 1024) ) {
        $file_contents .= $buffer;
    }

    return $file_contents;
    
}