FW: Hooking into template file accesses

Sorry if this is a re-post.  I had some list subscription trouble. 

> -----Original Message-----
> From: templates-admin-MnLy+PD7ppGDO3lXZvfOKmD2FQJk+8+b@xxxxxxxxxxxxxxxx 
> [mailto:templates-admin-MnLy+PD7ppGDO3lXZvfOKmD2FQJk+8+b@xxxxxxxxxxxxxxxx] On 
> Behalf Of Paul 
> LeoNerd Evans
> Sent: Monday, February 27, 2006 8:20 PM
> To: templates-MnLy+PD7ppGDO3lXZvfOKmD2FQJk+8+b@xxxxxxxxxxxxxxxx
> Subject: [Templates] Hooking into template file accesses
> 
[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) = @_;
        $self->{_my_mtime} = 0;
    }

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

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

    1;

Then you install the provider like this:

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

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

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

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

HTH
Philip