It is possible to pass class name and method instead of inline handler

lib/Plack/Middleware/SocketIO.pm

@@ -5,20 +5,29 @@ use warnings;
 
 use base 'Plack::Middleware';
 
-our $VERSION = '0.00902';
+our $VERSION = '0.00903';
 
-use Plack::Util::Accessor qw(resource handler);
+use Plack::Util ();
+use Plack::Util::Accessor qw(resource handler class method);
 
 use Plack::Middleware::SocketIO::Resource;
 
+sub new {
+    my $self = shift->SUPER::new(@_);
+
+    $self->handler($self->_get_handler);
+
+    return $self;
+}
+
 sub call {
     my $self = shift;
     my ($env) = @_;
 
     my $resource = $self->resource || 'socket.io';
     $resource = quotemeta $resource;
 
-    if ($env->{PATH_INFO} =~ m{^/$resource/}) {
+    if (defined $env->{PATH_INFO} && $env->{PATH_INFO} =~ m{^/$resource/}) {
         my $instance = Plack::Middleware::SocketIO::Resource->instance;
 
         return $instance->finalize($env, $self->handler)
@@ -28,6 +37,22 @@ sub call {
     return $self->app->($env);
 }
 
+sub _get_handler {
+    my $self = shift;
+
+    return $self->handler if $self->handler;
+
+    my $class = $self->class
+      or die q{Either 'handler' or 'class' must be specified};
+    my $method = $self->method || 'run';
+
+    Plack::Util::load_class($class);
+
+    $class->new;
+
+    return sub { $class->run };
+}
+
 1;
 __END__
 
@@ -58,6 +83,14 @@ Plack::Middleware::SocketIO - Socket.IO middleware
         $app;
     };
 
+    # or
+
+    builder {
+        enable "SocketIO", class => 'MyApp::Handler', method => 'run';
+
+        $app;
+    };
+
 =head1 DESCRIPTION
 
 L<Plack::Middleware::SocketIO> is a server implmentation of SocketIO in Perl.
@@ -83,6 +116,45 @@ All the transports are supported.
 For TLS/SSL a secure proxy is needed. C<stunnel> or L<App::TLSMe> is
 recommended.
 
+=head1 CONFIGURATIONS
+
+=over 4
+
+=item handler
+
+    enable "SocketIO",
+        handler => sub {
+            my $socket = shift;
+
+            $socket->on_message(sub {
+                my $socket = shift;
+            });
+
+            $socket->send_message('hello');
+        };
+
+=item class, method
+
+    enable "SocketIO", class => 'MyHandler', method => 'run';
+
+    package MyHandler;
+
+    sub new { ...  } # or use Moose, Boose, Goose, Doose
+
+    sub run {
+        my $self = shift;
+
+        return sub {
+
+            # same code as above
+        }
+    }
+
+Loads C<class> using L<Plack::Util::load_class>, creates a new object and runs
+C<run> method expecting it to return an anonymous subroutine.
+
+=back
+
 =head1 DEVELOPMENT
 
 =head2 Repository

t/lib/Handler.pm

@@ -0,0 +1,19 @@
+package Handler;
+
+use strict;
+use warnings;
+
+sub new {
+    my $class = shift;
+
+    return bless {}, $class;
+}
+
+sub run {
+    my $self = shift;
+
+    return sub {
+    };
+}
+
+1;

t/middleware.t

@@ -0,0 +1,21 @@
+use strict;
+use warnings;
+
+use lib 't/lib';
+
+use Test::More tests => 4;
+
+use_ok('Plack::Middleware::SocketIO');
+
+eval {
+    Plack::Middleware::SocketIO->new(app => sub { });
+};
+like $@ => qr/Either 'handler' or 'class' must be specified/;
+
+my $middleware =
+  Plack::Middleware::SocketIO->new(app => sub { }, handler => sub { });
+is ref($middleware->handler) => 'CODE';
+
+$middleware =
+  Plack::Middleware::SocketIO->new(app => sub { }, class => 'Handler');
+is ref($middleware->handler) => 'CODE';