Re: how to handle error with type constraint

Vincent,

The simplest way to do this is to catch the exception, so wrap the  
object creation inside an eval { } and if you get an exception write  
the info to your log file.

There is a way to alter the Moose error handling behavior, but it  
would be overkill in this case where simple exception handling would  
suffice.

- Stevan

On Sep 22, 2008, at 9:40 AM, vincent roudil wrote:

> Hello Moose,
> I am just starting to explore Moose. This is probably something  
> simple, but
> I can't figure out the best way to do this.
>
> With the Moose type constraint, I would like to get control of the  
> error
> handling when the type is invalid.
>
> Here is an example.
>
> a class host, with 2 attributes, name and ip_addr, with a control  
> on the IP
> address validity:
> ##### package host.pm
> package host;
> use Moose;
> use Moose::Util::TypeConstraints;
>
> use Regexp::Common qw /net/;
> subtype IPAddr
> => as Str
> => where {/^$RE{net}{IPv4}$/}
>  => message { 'invalid IP address'};
>
> has 'ip_addr' => (isa => 'IPAddr', is => 'ro', required => 1);
> has 'name' => (isa => 'Str',      is => 'ro', required => 1);
> 1;
> ##### end package host.pm
>
> The type constraints works fine. Only that when the IP address is  
> invalid
> the program dies, with great verbosity.
>
> I would just like when IP address is invalid, to print a message in  
> a log
> file, and that the creation of the instance fails quietly, so I  
> could use
> the host class like this:
>
> ##### main.pl:
> use host;
>
> my $h=host->new(name=>'jupiter', ip_addr=>'10.10.10.1');
>
> if ($h) {
>  print $h->name." created successfully with the IP address ".$h- 
> >ip_addr;
> }
>
> If someone could point me to the right direction, that would be great.
>
> Thanks in advance.
>
> Vincent.