The document discusses using MooseX::DataModel to parse JSON data into Perl objects. It shows how JSON data representing a list of users can be defined as objects with a UserList class containing an array of User objects, each with a name attribute. This allows accessing and manipulating the data like normal Perl objects and adds validation against the class schemas. Methods can also be defined on the generated classes. The document expresses frustration with working directly with complex JSON data and advocates using MooseX::DataModel as a cleaner approach.

1. Hi!

2. I HATE JSON

3. { “users”: [
{ “name”: “Joe” },
{ “name”: “Katy” },
]}

4. {“users”:[{ “name”:“Joe” },{ “name”:“Katy” }]}

5. my $var = { users => [
{ name => ‘Joe’ },
{ name => ‘Katy’ },
]
};
foreach my $user @{ $var->{ users } } {
…
}
Parsing JSON gives you this
Access to the data is like this

6. Working with complex datastructures:

7. { users => [
{ name => ‘Joe’ },
{ name => ‘Katy’ },
]
}
USERLIST
USER

8. MooseX::DataModel

9. Why not express the structure like this?
package UserList;
use MooseX::DataModel;
array users (isa => ‘User’);
1;
package User;
use MooseX::DataModel;
key name => (isa => ‘Str’, required => 1);
1;
my $ul =UserList->parse($json);
say $ul->users->[0]->name;
This even validates the JSON to the schema!

10. We can even tack methods on the objects!
package UserList;
use MooseX::DataModel;
array users (isa => ‘User’);
sub send_mail_to_all { … for ($self->users) { … } … };
1;
package User;
key name => (isa => ‘Str’, required => 1);
1;
my $ul = UserList->parse($json);
$ul->send_mail_to_all;

11. I HATE working with JSON
complex datastructures
(that convey object-ish things)

12. And JSON

13. Because this… is not valid JSON 
{ “users”: [
{ “name”: “Joe” },
{ “name”: “Katy” },
]}

14. Because this… is not valid JSON 
{ “users”: [
{ “name”: “Joe” },
{ “name”: “Katy” },
]}
Trailing comma is a syntax error 

15. GitHub
http://github.com/pplu/moosex-datamodel
Join me if you have the same pain
Note: highly experimental code. Not released on CPAN until it looks a
bit decent

16. Thanks!