virtual attributes with validators, splitting/joining a column value to create them

I have an existing SQL table the schema of which I cannot modify, and I would like to create a Lithium data model for it. The problem is that one column contains multiple "fields" separated by a special character.

E.g.

data = "username|email|age"

I would need to:

split the value of the column after the row was read, and create "virtual" attributes
be able to assign to these virtual attributes
join the virtual attributes to create a valid column value before save
create validators for the virtual attributes
use html->form to create form fields for the virtual attributes

I tried to figure out how to do this, but there seems to be no easy way. Not even a hard way :) Any ideas?

Solution

Magic virtual attributes aren't supported in Lithium out of the box. There is an ongoing work and discussion about that here https://github.com/UnionOfRAD/lithium/pull/569.

That said, you can almost solve this problem with instance methods in your Model + filters on save and find.

An after find filter, which sets username, email and age, attributes to your entity after reading it.
A before save filter, which join those attributes in a data attributes before saving the entity, and unsets username, email and age (to avoid saving them).

Maybe you'll need Model instance methods too like

public function username($entity) {
      /* split here $entity->data by "|" and keep only what do you want */
      return $username;
}

Then you can call anywhere $user->username() to get the username only.

That should solve your problem until this feature will be shipped in Lithium.