[Templates] Hooking into template file accesses

[Garrett, Philip (MAN-Corporate)]

> -----Original Message-----
> From: templates-admin@template-toolkit.org
[mailto:templates-admin@template-toolkit.org] On Behalf Of Paul LeoNerd
Evans
> Sent: Monday, February 27, 2006 8:20 PM
> To: templates@template-toolkit.org
> Subject: [Templates] Hooking into template file accesses
>=20
[snip]
>
>   2. It tracks the latest mtime of any file (or other data) used
during
>      the building of the page, in order to set the "Last_Modified:"
>      header on reply and to implement the "If_Modified_Since:" logic.

You could subclass Template::Provider::fetch and add your mtime checking
code to it.  (*untested code*) e.g.

    package My::Mtime::Provider;
    use base qw(Template::Provider);

    sub init_mtime {
        my ($self) =3D @_;
        $self->{_my_mtime} =3D 0;
    }

    sub check_mtime {
        my ($self,$doc) =3D @_;
        # remember this mtime if it's newer than
        # anything else we've seen
        if ($doc && $doc->modtime > $self->{_my_mtime}) {
            $self->{_my_mtime} =3D $doc->modtime;
        }
    }
   =20
    sub get_mtime {
        my ($self) =3D @_;
        return $self->{_my_mtime};
    }

    sub fetch {
        my $self =3D shift;
        my ($doc,$reason) =3D $self->SUPER::fetch(@_);
        $self->check_mtime($doc);
        return ($doc,$reason);
    }

    1;

Then you install the provider like this:

    my %config =3D ( COMPILE_DIR =3D> '/wherever', @other_opts );
    my $provider =3D My::Mtime::Provider->new(\%config);
    my $template =3D Template->new(%config,
        LOAD_TEMPLATES =3D> [$provider]);

Then, every time you process a template, do this:

    $provider->init_mtime();
    $template->process($template_name) || die $template->error;
    my $mtime =3D $provider->get_mtime();

I hope the code doesn't have too many bugs in it.

HTH
Philip