Yii Validation scenarios

Validation scenarios

February 16th, 2009

As of Yii 1.0.2 you may now define validation scenarios. This is very useful if for instance you have multiple places in your application that you validate a model, but in each instance you may want different validation rules. For instance, perhaps in your user registration form you want to have the “username”, “email” and “password” fields to be required, while on your “user recovery” page, you only want the “email” field to be required. You may see a problem here. If you set all the fields to be required, then your user recovery page won’t work, as it does not allow a user to supply neither a password nor a username.
The perfect solution to this are validation scenarios. You can attach a validation scenario to a validation rule through the ‘on’ property. You may already know you can set the ‘on’ property to either ‘insert’ or ‘update’, which will automatically cause the rule to only be used on the corresponding type of save. However sometimes these two options are not enough. So now with this new enhancement, you may set it to any value you want. Let me show an example:

//in user model
public function rules() {
 return array(
  //Set required fields
   //Applies to 'register' scenario
   //Note 'on' property
  array('username, password, password_repeat, email', 'required', 'on' => 'register'),
 
  //Applies to 'recover' scenario
  array('email', 'required', 'on' => 'recover'),
 
  //Applies to all scenarios
  array('username, password', 'length', 'max'=>35, 'min'=>3),
 
  //This rule checks if the username is unique in the database in
  //the 'register' scenario (we don't want it to check for uniqueness
  //on the login page for instance)
  array('username', 'unique', 'on' => 'register'),
 
  //This rule applies to 'register' and 'update' scenarios
  //Compares 'password' field to 'password_repeat' to make sure they are the same
  array('password', 'compare', 'on' => 'register, update'),
 );
}

With this setup Yii will be able to tell which fields are required in which scenarios. As a bonus I threw some other rules for example. Reading the comments will give you an understanding of that. You may also note from the ‘compare’ rule that you may define a rule to be used on multiple scenarios by separating them with commas.
Now when you wish to run validation under a specific scenario you must define it in when calling CModel::validate(), as so

$user->validate(''); //runs validation under the given scenario
 
//example:
if ($user->validate('register')) {
 $user->save(false);
}

So the above example will validate the user under the ‘register’ scenario.