[Catalyst] RFC: Catalyst::Plugin::SpecialAction::Trail

[BUCHMULLER Norbert]

Hi All,

i was looking for something that's similar to "auto" in the sense that it
also runs in all the parent controllers of the dispatched action, but is
run right before "end" (that dispatches to the view).

The actual problem that led to this was that I had to log the processing
time of the request *excluding* the processing time of the view
component. Since I had some Catalyst::Controller::REST based controllers
(that inherit their own "end" actions from C:P::REST) I could not put the
logging in the root "end" action as it did not run for the C:P::REST based
controllers. Overriding the "end" in each REST controller to call the
logging is error-prone (even with a role, as one can easily forget to
apply the role when writing the next REST controller). And since I wanted
to exclude the processing time of the view,
Catalyst::Plugin::RunAfterRequest alone did not solve my problem either -
it runs after the view, thus it's perfect for the actual logging but is
too late to measure the time elapsed since the beginning of the request.

I did not find anything like that, so I wrote this module:

https://github.com/mendel/Catalyst-Plugin-SpecialAction-Trail/blob/master/lib/Catalyst/Plugin/SpecialAction/Trail.pm

Now the code looks like this:

package MyApp;

...

use Catalyst qw/
    ...
    RunAfterRequest
    SpecialAction::Trail
/;

...

package MyApp::Controller::Root;

...

__PACKAGE__->config(namespace => '');

...

sub trail : Private {
    my ($self, $c) = @_;

    # $c->stash->{req_start_time} is set to gettimeofday()
    # at the beginning of request processing
    my $time_elapsed = tv_interval($c->stash->{req_start_time});

    $c->run_after_request(sub {
        <actual logging>
    });
}

sub end : Private : ActionClass('RenderView') {
    ...
}


Comments welcome.

norbi