Validating a User via Save Method

Question

I'm fairly new to object oriented programming here and am trying to get my head around the best way to go about creating Users and Validating them in the system.

My first attempt is below and my main questions apart from does it all seem correct is in regards passing a validator class to the save function and pros/cons to this.

A lot of the functionality has been stripped back to enable you to read it a bit easier, including removing any getters and setters but please assume they are there:

User Model

class User implements Validateable {
 protected $name;
 protected $email;
 protected $validator;
 // getters and setters for name, email, validator here
 public function save( Validator $validator ) {
 $this->validator = $validator; 
 if( $this->validator->validate( $this ) )
 return true;
 return false;
 }
 public function getRules() {
 return [ 
 'name' => new NameValidator( $this->name ), 
 'email' => new EmailValidator( $this->email )
 ];
 }
}

Abstract Validator

abstract class ValidatorAbstract {
 protected $errors;
 public function getErrors() {
 return $this->errors;
 }
}

Name Validator

class NameValidator extends ValidatorAbstract {
 protected $name;
 protected $errors;
 public function __construct( $name ) {
 $this->name = $name;
 }
 public function validate() {
 if( empty( $this->name ) ) 
 $this->errors[] = 'Invalid Name';
 if( $this->errors )
 return false;
 return true;
 }
}

Email Validator

class EmailValidator extends ValidatorAbstract {
 protected $email;
 protected $errors;
 public function __construct( $email ) {
 $this->email = $email;
 }
 public function validate() {
 if( !filter_var( $this->email, FILTER_VALIDATE_EMAIL ) ) :
 $this->errors[] = 'Invalid Email';
 endif;
 if( $this->errors )
 return false;
 return true;
 }
}

User Validator

class UserValidater implements Validator {
 protected $data;
 protected $rules;
 protected $errors;
 public function validate( Validateable $obj ) {
 $this->rules = $obj->getRules();
 foreach( $this->rules as $rule ) :
 if( !$rule->validate() )
 $this->errors[] = $rule->getErrors();
 endforeach;
 if( $this->errors )
 return false;
 return true;
 }
 public function getErrors() {
 return $this->errors;
 }
}

Validator Interface

interface Validator {
 public function validate( Validateable $data );
 public function getErrors();
}

Validateable Interface

interface Validateable {
 public function getRules();
}

And finally some example code using all of the above:

$user = new User;
$user->setName( 'Peter' );
$user->setEmail( '[email protected]' );
if( $user->save( new UserValidater ) ) :
 // do some stuff
else :
 $errors = $user->getValidator()->getErrors();
 // do some stuff with the errors
endif;

• Phrancis: Welcome to Code Review! Does the code work as is presented, with the removed functionality?
• Peter Featherstone: Hi @sᴉɔuɐɹɥԀ It won't without the getters and setters, I will remember that in future!
• Phrancis: It's better to post the whole code, some reviewers like to actually run the code so they can find ways to improve it without breaking it. See the Help Center for more information.

Answer 1

It's better to separate the validation from the save operation and to use a constraint object to setup the rules which be applied to the entity. So you get a better separation of concern, which is one of the keys to good OOP architecture. I propose something like this:

$user = new User;
$user->setName( 'Peter' );
$user->setEmail( '[email protected]' );
$validator = new Validator(new UserConstrainte)); 
if( $validator->validate($user)){
 $databaseStuff->save($user)
} else {
 $error = $validator->getErrors()
}

I advise you to check the validator component from symfony2: https://github.com/symfony/Validator which is really well designed.

• Peter Featherstone: Hey liobase, feels like you are following me around here! My own personal guru, thanks for all your help so far... I like the idea of keeping the constraints in a seperate User Contstraints class and having one master Validator class.
• lilobase: You are welcome, your questions are interesting and focused on software architecture, which is what I do :). And I can say you are in the right way!
• Peter Featherstone: Thanks lilo, I have started to become incredibly interested in software architecture recently after getting asked to build some quite substantial projects so I really need to get this stuff right... Can you give me any tips on where to go for advice/books/websites in this regard or how you learnt?
• lilobase: I give you my twitter account, follow me so I can send you some info through pm: @lilobase
• Peter Featherstone: Thanks, I reallly appreciate all your help and taking the time... I just followed you, mine is @plumapiedra