Dynamic model relations in CakePHP - cakephp

Question

I'm trying to define the relations for a specific Model depending on environment variables.
Like this:
class Book extends AppModel {
public function __construct($id = false, $table = null, $ds = null) {
parent::__construct($id, $table, $ds);
if (Configure::read('prefix') == 'admin') {
$this->hasMany['Page'] = array(
// ...
'conditions' => array( /* all pages */ )
);
} else {
$this->hasMany['Page'] = array(
// ...
'conditions' => array( /* only public pages */ )
);
}
}
}
You could argue that I should apply these conditions in the query. But because I'm working with deeply nested relations I wanted to keep conditions centralised.
Now the problem that occurs is: if the Page model has relations to e.g. the Paragraph model and from the BookController I'm trying:
$this->Book->find('first', array(
'conditions' => array('Book.id'=>1),
'contain' => array('Page' => array('Paragraph'))
));
... CakePHP will tell me that Paragraph is not related to the Page model.
If I create the relation by defining a model attribute all goes well:
class Book extends AppModel {
public $hasMany = array(
'Page' => array(
// ...
)
);
}
Why is this? Do I need to manually establish those relations? Is my timing (__construct()) incorrect and should this be done elsewhere?
Kind regards,
Bart

Answer 1

Yes, your timing is incorrect. You should either apply these configuration options before invoking the parent constructor:
if (Configure::read('prefix') == 'admin') {
// ...
}
parent::__construct($id, $table, $ds);
or use Model::bindModel() instead which will create the necessary links:
$this->bindModel(
array('hasMany' => array(
'Page' => array(
// ...
'conditions' => array( /* ... */ )
)
)),
false
);
See also http://book.cakephp.org/...html#creating-and-destroying-associations-on-the-fly