Dev411 Blog

Catalyst::View::TT 0.23, the Template Toolkit View for the Catalyst MVC framework, was recently released on May 27, 2006 and just in time. It breaks out the render functionality as a separate method from the process method allowing direct rendering of TT templates in addition to handling the overall catalyst response. This is useful when you want to render a template for say an email body or fragments in a JSON response. The render method is accessed as follows:

my $output = $c->view('TT')->render(
    $c, 'mytemplate.tt', \%args
);

Prior to this, Catalyst::Plugin::SubRequest was the recommended way for rendering a TT template when C::V::TT was being used, e.g. the email body example in the SubRequest POD. This method is a kludge because SubRequest is designed to make public action requests, not for just rendering a template. I didn't mind using SubRequest just once to render a TT template for email, however I grew concerned when I starting using it multiple times to render HTML fragments to return via JSON. I was converting more private methods to public actions just so they could be called by SubRequest when I decided this was too kludgy and went to see if I could call TT directly. I went code diving in C::V::TT where I found the render method in 0.23 on search.cpan.org. I had to install 0.23 from the tarball directly since my CPAN shell would only give me 0.22.

SubRequest also seems to have a problem in that it nukes the Catalyst::Request parameters so $c->req->params is no longer populated correctly after a $c->subreq call. This created strange results without errors that were hard to pinpoint for me. On #catalyst, network_ninja mentioned he got around this problem by copying the params to $c->req->parameters and giving that to SubRequest. My solution is to just stop using SubRequest, at least when I only want to render a template.

Thanks to the Cat team for breaking out render and releasing it just when I went looking for it.