slide3.pl

#!/opt/perl

use Mojolicious::Lite;

get '/' => sub {
    my $self = shift;

    $self->render("slash");
};

get '/add' => sub {
    my $self = shift;

    ++$self->session->{counter};

    $self->render("add");
};

get '/sub' => sub {
    my $self = shift;

    --$self->session->{counter};

    $self->render("sub");
};

app->secrets(["Supers secret."]);
app->start;

__DATA__

@@ slash.html.ep
Counter: <%= session("counter") // "undef" %>

@@ add.html.ep
Add: <%= session("counter") // "undef" %>

@@ sub.html.ep
Subtract: <%= session("counter") // "undef" %>