Constructing a Plack app with images search path and sessions

NblogConstructor.pm

around psgi_callback => sub {
    my $orig = shift;
    my $self = shift;
    my $cascade = Plack::App::Cascade->new;
    my $favicon_c = Plack::App::Cascade->new;
    for my $root ( $self->static_roots ){
        $cascade->add( Plack::App::File->new(root => $root )->to_app );
        $favicon_c->add( Plack::App::File->new( file => "$root/images/favicon.ico" )->to_app );
    };
    my $app = Plack::App::URLMap->new;
    $app->map( '/static', $cascade );
    $app->map( '/favicon.ico', $favicon_c );
    $app->map( '/', $self->$orig( @_ ) );
    return Plack::Middleware::Session->wrap(
        $app->to_app,
        store => Plack::Session::Store::Cache->new(
            cache => CHI->new(driver => 'FastMmap')
        )
    );
};