use strict;
use CGI '3.30', ();
my $q = CGI->new;

sub GET($$) {
    my ($path, $code) = @_;
    return unless $q->request_method eq 'GET' or $q->request_method eq 'HEAD';
    return unless $q->path_info =~ $path;
    $code->();
    exit;
}

eval {

    GET qr{^/=$} => sub {
        print $q->header('text/html');
        print $q->h1('REST API Documentation');
    };

    GET qr{^/=/model/book/id/([\d-]+)$} => sub {
        my $id = $1;

        # Look up the resource file
        my $filename = get_local_path($id);
        if (-f $filename) {
            ..
        };
    };

};
if( $@ ) {
    print "There was an error.";
};