method modifiers with moose perl - perl

Question

I need to filter the "string" passed to the attribute "query"
and create a url with the filtered value.
my code
package Search;
use Any::Moose;
has query => qw{ is ro isa Str required 1 };
# my method modifiers
around 'query' => sub {
my $orig = shift;
my $self = shift;
my $content = $self->$orig(#_);
# simple filter
$content =~ s{[^\w\-\s]}{}gi;
return $content;
};
sub create_uri {
my $self = shift;
my $uri = "http://localhost/search/".$self->{query};
return $uri;
};
1;
package main;
my $obj = Search->new({
query => 'foo##$%#%##&-**bar###%!',
});
print $obj->query."\n";
print $obj->create_uri."\n"; # BAD
output here :
print $search->query;
foo-bar , as expected.
When I call "create_uri"
print $search->create_uri;
output :
http://localhost/search/foo##$%#%##&-**bar###%!
The "query" is completely dirty!
How to solve this?

Answer 1

A couple more approaches for you to explore:
Use a BUILDARGS method in your class to clean up the query string before it gets assigned to the attribute at construction.
sub BUILDARGS {
my $type = shift;
my $args = ref $_[0] eq 'HASH' ? shift : {#_};
$args->{query} =~ s{[^\w\-\s]}{}gi;
return $args;
}
Use type coercion.
subtype 'SafeStr', as 'Str', where {!/[^\w\-\s]/};
coerce 'SafeStr', from 'Str', via {
my $str = $_;
$str =~ s/[^\w\-\s]//gi;
return $str;
};
has 'query' => (
is => 'ro',
isa => 'SafeStr',
required => 1,
coerce => 1,
);

Answer 2

When you call print $obj->query you are calling the /subroutine/ called query, which calls your around sub. When you call $self->{query} from within create_uri you access the /attribute/ called query. There are two solutions:
1) Replace $self->{query} with $self->query
2) Instead of using around query, use the trigger option on the attribute, which calls a function every time the attribute is set. See http://metacpan.org/pod/Moose for information.