Mojo::Pg notify on db close

gistfile1.txt

--- PubSub.pm.orig      2018-11-07 22:09:03.636066615 +1030
+++ PubSub.pm   2018-11-07 22:21:28.613982320 +1030
@@ -29,8 +29,12 @@
 sub unlisten {
   my ($self, $name, $cb) = @_;
   my $chan = $self->{chans}{$name};
+  my $unlisten = $cb ? grep { $cb eq $_ } @$chan : 1;
   @$chan = $cb ? grep { $cb ne $_ } @$chan : ();
-  $self->_db->unlisten($name) and delete $self->{chans}{$name} unless @$chan;
+  if (!@$chan) {
+    $self->_db->unlisten($name) if $unlisten;
+    delete $self->{chans}{$name};
+  }
   return $self;
 }
 
@@ -50,7 +54,11 @@
       for my $cb (@cbs) { $self->$cb($payload) }
     }
   );
-  $db->once(close => sub { $self->{pg} and $self->_db if delete $self->{db} });
+  $db->once(close => sub {
+    $self->emit(disconnect => $db);
+    delete $self->{db};
+    $self->reset;
+  });
   $db->listen($_) for keys %{$self->{chans}}, 'mojo.pubsub';
   $self->emit(reconnect => $db);
 
-----8<-----

#!/usr/bin/perl

use Mojolicious::Lite;
use Mojo::Pg;

helper pg => sub { state $pg = Mojo::Pg->new('postgresql:///') };

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

  my $pubsub = $c->pg->pubsub;

  my $listen_cb = eval {
    $pubsub->listen(test => sub {
      $c->write("notify\n");
    });
  };
  if ($@) {
    $c->write("db connection failed: $@\n");
    $c->finish;
    return;
  }

  $c->write;
  $c->write("ready!\n");

  my $disconnect_cb = $pubsub->on(disconnect => sub {
    $c->finish;
  });

  $c->on(finish => sub {
    $pubsub->unlisten(test => $listen_cb);
    $pubsub->unsubscribe(disconnect => $disconnect_cb);
  });
};

app->start;