On 25/01/2014 10:58 AM, neil.lunn wrote:
Hi all,
Was just thinking through setting up various project minting files and
got to looking at the default Catalyst app layout from the helper.
Specifically I wondered how much the defaults were just being cargo
culted, and specifically addressing my dislike for overuse of inline
__PACKAGE__ calls when we have Moose and BUILD available. So random
musings below:
Oops. Big fail. Forgot the most important bit. See edit
Here's a sensible base class for the App context:
package Catalyst::BaseClass;
use Moose;
use namespace::autoclean;
use Catalyst::Runtime 5.80;
use Catalyst qw/ PluginLoader /; # Should be all we need
extends 'Catalyst';
our $VERSION = '0.01';
sub hook_config {
my $self = shift;
my $class = ref($self);
# Set some basic defaults
return {
name => $class,
enable_catalyst_header => 1, # Send X-Catalyst header
};
}
sub hook_logger {
# Do nothing by default. Setup will take care of it.
}
sub BUILD {
my $self = shift;
my $class = ref($self);
unless ( $self->setup_finished ) {
# Setup Config
$self->config(
%{ $self->hook_config }
);
# Place a hook to hang a logger on before setup is called
$self->hook_logger();
$class->setup();
}
}
As you can see by the "hook" methods, this was "take 2" where I was
abstracting my personal "cause" from the general base class. By
placing the hooks in you can abstract in your application, as in:
package YourApp::Web;
use Moose;
use namespace::autoclean;
extends 'Catalyst::BaseClass';
our $VERSION = '0.01';
our $load_class = \&Plack::Util::load_class;
around 'hook_config' => sub {
my $orig = shift;
my $self = shift;
my $class = ref($self);
my $basename = $class;
$basename =~ s/::.+//g;
use Hash::Merge qw/merge/;
# Setup Config
my $configclass = $load_class->( "${basename}::Config" );
return merge( $self->$orig, $configclass->config || {} );
};
override 'hook_logger' => sub {
my $self = shift;
# Optional logger from class
my $logger = $self->config->{Logger};
if ( defined $logger ) {
die "Config Logger requires a Class key"
unless $logger->{Class};
my $logclass = $load_class->( $logger->{Class} );
$self->log( $logclass->new( @{ $logger->{Config} || [] } ) );
$self->log->debug( qq/Initialized logger: "$logclass"/ );
}
};
Now, realistically even the *second* and extended implementation is
still notably generic and *for me* this is even enough to place as a
*base class* to every application as this is how I will lay things
out. Plack::Util seems to be a fair assumption to be loaded as the end
result is a PSGI app, and Plack::Runner is going to pull this in. For
the nosy, the Logger class in this case is a mere wrapper around
Log::Log4perl in this case, and would only get the logger instance if
it had already been initialized. You can (and I do) set up Plack
middleware to do the same thing, making the same logger available to
other PSGI parts that might be used in your application, all without
needing to wrap context to get at the logger, or explicitly call
Log::Log4pperl::get_logger as we might just want to change that to a
different logger at some stage.
So general thoughts are:
1. Have a config class that is external to Catalyst logic. You can use
it elsewhere without hassle.
2. Have a hook to hang that config on and get it early; because
3. Hang a logger on a hook before 'setup' is called so you can get the
startup logging on debug
4. Pull in the plugins from Config so there isn't a need to keep
modifying that code in the context class for every app
Also minimising the selection of Plugins. I do try to keep this to
session and auth stuff for convenience, and again have these as just
thin layers over Plack Middleware. Other things can be delegated to
role applicator stuff, which I haven't typed in here.
Anyone else have thoughts? Alternate favourite methods for layout?
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