How can I share validation arrays between models? - php

Question

For example, I have several models that have name and uid fields but some models do not have them. I want all models that have those fields to use the following rules, however, I don't want to add the following block of code to each model.
public $validate = array(
'name' => array(
array(
'rule' => array('between', 1, 25),
'message' => 'Name must contain %d to %d characters',
'required' => true
),
array(
'rule' => array('custom', AppModel::REGEX_NAME),
'message' => 'Name contains invalid characters.'
)
),
'uid' => array(
'rule' => 'uuid',
'message' => 'uid is not valid.',
'required' => true
),
);
I've considered adding the rules to AppModel by setting public $validate. This leads to the following problems.
Models without those fields always fail validation because required is true.
If you set public $validate in a model, it will not inherit the rules from AppModel.
I'm sure this can be handled by adding validation on-the-fly (I'm thinking beforeValidate() in AppModel) but I would like to know how others are handling this.
Does anyone know a better way?

Answer 1

Personally I would just copy/paste the validation array in each model.
If that isn't what you want to do, you could do something like extend AppModel to MyAppModel. Within MyAppModel set public $validate = array(...), and for the models needing those validation rules simply extend MyAppModel instead of AppModel in your class declaration.
As for problem #2, you need to call parent::validate to retrieve that array and then supplement it with further rules. My initial thought would be to create an array for the new rules not found in MyAppModel and then array_merge with that array + parent::validate.

Answer 2

This is usually handled by just copy/pasting the validation array or setting up your "normal" validation rules into your bake template. That way, they're there by default upon starting each project.
Or per the comment above, you can use a Behavior - though unless you have a LOT of models, personally, I think that's overkill.

Answer 3

You could add a method like mergeDefaultRules() to your AppModel that can be called from
within each models beforeValidate() that merges the default rules
with the model specific rules
You could use traits instead of using an AppModel method for that - if you can use php 5.4
You could use a behavior
I would go for 1 or 2.
// In your AppModel
public function mergeDefaultRules() {
$this->validate = array_merge($this->validate, array(/* Default rules here */));
}
// In your specific model
public function beforeValidate($options = array()) {
$this->mergeDefaultRules();
return true;
}