design pattern: Chain Of Responsibility

GET.pm

package HTTP::RequestHandler::GET;
use base qw/HTTP::RequestHandler/;
use strict;
use warnings;

sub handle_request {
    my ($self, $request) = @_;
    return if $request->method ne 'GET';
    warn 'Requested method is GET: ' . $request->uri;
}

1;

POST.pm

package HTTP::RequestHandler::POST;
use base qw/HTTP::RequestHandler/;
use strict;
use warnings;

sub handle_request {
    my ($self, $request) = @_;
    return if $request->method ne 'POST';
    warn 'Requested method is POST: ' . $request->uri;
}

1;

request.pl

#!/usr/bin/env perl
use strict;
use warnings;
use FindBin::libs;
use HTTP::RequestProcessor;
use HTTP::RequestHandler::GET;
use HTTP::RequestHandler::POST;

my $p = HTTP::RequestProcessor->new;
$p->add_handler( HTTP::RequestHandler::GET->new );
$p->add_handler( HTTP::RequestHandler::POST->new );

$p->handle_request( HTTP::Request->new( GET => 'http://github.com' ) );
$p->handle_request( HTTP::Request->new( POST => 'http://github.com' ) );

1;

RequestHandler.pm

package HTTP::RequestHandler;
use strict;
use warnings;
use base qw/Class::Accessor::Lvalue::Fast/;

1;

RequestProcessor.pm

package HTTP::RequestProcessor;
use strict;
use warnings;
use HTTP::RequestHandler;
use HTTP::Request;
use base qw/Class::Accessor::Lvalue::Fast/;

__PACKAGE__->mk_accessors(qw/handlers/);

sub add_handler {
    my ($self, $handler) = @_;
    push @{$self->{handlers}}, $handler;
    $self;
}

sub handle_request {
    my ($self, $request) = @_;
    for my $handler (@{$self->handlers}) {
        $handler->handle_request($request) and return;
    }
    die "Request could not be handled";
}

1;