Self Validating Value Objects and Entities (Laravel Implementation)

AbstractEntity.php

<?php

abstract class AbstractEntity extends AbstractValueObject
{
    /**
     * Offset Set
     *
     * @param  mixed $offset
     * @param  mixed $value
     *
     * @return void
     */
    public function offsetSet($offset, $value)
    {
        $this->input[$offset] = $value;

        if ($this->validate) {
            $this->validate();
        }
    }

    /**
     * Offset Unset
     *
     * @param  mixed $offset
     *
     * @return void
     */
    public function offsetUnset($offset)
    {
        unset($this->input[$offset]);

        if ($this->validate) {
            $this->validate();
        }
    }
}

AbstractValueObject.php

<?php

use ArrayAccess;
use Illuminate\Contracts\Support\Arrayable;
use Illuminate\Contracts\Support\Jsonable;
use JsonSerializable;
use ValidatorInvalidArgumentException;

abstract class AbstractValueObject implements ArrayAccess, Arrayable, Jsonable, JsonSerializable
{
    /**
     * Input
     *
     * @var array
     */
    protected $input;

    /**
     * Validate
     *
     * @var bool
     */
    protected $validate;

    /**
     * Rules
     *
     * @var array
     */
    public $rules = [];

    /**
     * Messages
     *
     * @var array
     */
    public $messages = [];

    /**
     * Validator
     *
     * @var Illuminate\Validation\Factory
     */
    protected $validator;

    /**
     * Constructor
     *
     * @param array $input Input
     */
    public function __construct(array $input, $validate = true)
    {
        $this->validator = app()->make('validator');
        $this->input     = $input;
        $this->validate  = $validate;

        if ($this->validate) {
            $this->validate();
        }
    }

    /**
     * Get Input
     *
     * @return array Input
     */
    public function getInput()
    {
        return $this->input();
    }

    /**
     * Validate
     *
     * @return null|Dingo\Api\Exception\ValidationHttpException
     */
    public function validate()
    {
        $validator = $this->validator->make($this->input, $this->rules, $this->messages);

        if ($validator->fails()) {
            $exception = new ValidatorInvalidArgumentException();
            
            $exception
                ->setMessage('This is invalid')
                ->setErrors($validator->errors())
                ->setInput($this->input);
                
            throw $exception;
        }
    }

    /**
     * Offset Exists
     *
     * @param  mixed $offset
     *
     * @return bool
     */
    public function offsetExists($offset)
    {
        return isset($this->input[$offset]);
    }

    /**
     * Offset Get
     *
     * @param  mixed $offset
     *
     * @return mixed
     */
    public function offsetGet($offset)
    {
        return $this->input[$offset];
    }

    /**
     * Offset Set
     *
     * @param  mixed $offset
     * @param  mixed $value
     *
     * @return void
     */
    public function offsetSet($offset, $value)
    {
        return;
    }

    /**
     * Offset Unset
     *
     * @param  mixed $offset
     *
     * @return void
     */
    public function offsetUnset($offset)
    {
        return;
    }

    /**
     * To Array
     *
     * @return array Array of validated inputs
     */
    public function toArray()
    {
        return array_only($this->input, array_keys($this->rules));
    }

    /**
     * Json Serialize
     *
     * @return array Convert the object into something JSON serializable.
     */
    public function jsonSerialize()
    {
        return $this->toArray();
    }

    /**
     * To Json
     *
     * @return string Json string of validated inputs
     */
    public function toJson($options = 0)
    {
        return json_encode($this->jsonSerialize(), $options);
    }
}

AuthController.php

<?php

use ValidatorInvalidArgumentException;

class AuthController extends ApiController
{
    /**
     * Auth Service
     *
     * @var AuthService
     */
    protected $auth_service;

    /**
     * Constructor
     *
     * @param AuthService $auth_service Auth Service
     */
    public function __construct(AuthService $auth_service)
    {
        $this->auth_service = $auth_service;
    }

    
    /**
     * Authenticate
     *
     * @param Request $request Request
     *
     * @return Response Response
     */
    public function authenticate(Request $request)
    {
        $credentials = new CredentialsEntity($request->only('email', 'password'));

        try {
            $token = $this->auth_service->authenticate($credentials);
        } catch (ValidatorInvalidArgumentException $exception) {
            return [
                'message' => $exception->getMessage(),
                'errors'  => $exception->getErrors(),
                'input'   => $exception->getInput(),
            ];
        }

        return [
            'token' => $token
        ];
    }
}

AuthService.php

<?php

class AuthService
{
    /**
     * Authenticate
     * 
     * @param CredentialsEntity $credentials Credentials
     * 
     * @return string Token
     */
    public function authenticate(CredentialsEntity $credentials)
    {
        $token = ''; // Do something with valid $credentials here
        
        return $token;
    }
}

CredentialsEntity.php

<?php

class CredentialsEntity extends AbstractEntity
{
    /**
     * Rules
     *
     * @var array
     */
    public $rules = [
        'email'    => 'required|email',
        'password' => 'required',
    ];
}

CredentialsValueObject.php

<?php

class CredentialsValueObject extends AbstractValueObject
{
    /**
     * Rules
     *
     * @var array
     */
    public $rules = [
        'email'    => 'required|email',
        'password' => 'required',
    ];
}

SomeFile.php

<?php

// Value Objects are immutable.
$credentials = new CredentialsValueObject(['email' => '[email protected]', 'password' => 'baz']);

print $credentials['email']; 
// Prints email.

print isset($credentials['email']);
// Prints `true`.

print_r($credentials->toArray());
// Prints array of input.

print $credentials->toJson();
// Prints input in json format.

$credentials['something'] = 'else';
print $credentials['something'];
// The key will not exist.

// Entities are mutable.
$credentials = new CredentialsEntity(['email' => '[email protected]', 'password' => 'baz']);

unset($credentials['email']);
// Removes `email` key from input property in object and then revalidates. Validation fails.

$credentials['something'] = 'else';
print $credentials['something'];
// Prints `else`.

ValidatorInvalidArgumentException.php

<?php

use InvalidArgumentException;
use Illuminate\Support\MessageBag;

class ValidatorInvalidArgumentException extends InvalidArgumentException
{
    /**
     * Errors
     *
     * @var Illuminate\Support\MessageBag
     */
    protected $errors = [];

    /**
     * Input
     *
     * @var array
     */
    protected $input = [];

    /**
     * Constructor
     *
     * @param string         $message  Message
     * @param integer        $code     Code
     * @param Exception|null $previous Previous
     */
    public function __construct($message = '', $code = 0, Exception $previous = null)
    {
        parent::__construct($message, $code, $previous);

        $this->errors = new MessageBag;
    }

    /**
     * Set Message
     *
     * @param string $message Message
     *
     * @return ValidatorInvalidArgumentException
     */
    public function setMessage($message = '')
    {
        $this->message = $message;

        return $this;
    }

    /**
     * Set Errors
     *
     * @param MessageBag $errors Errors
     */
    public function setErrors(MessageBag $errors)
    {
        $this->errors = $errors;

        return $this;
    }

    /**
     * Get Errors
     *
     * @return MessageBag Errors
     */
    public function getErrors()
    {
        return $this->errors;
    }

    /**
     * Set Input
     *
     * @param array $input Input
     */
    public function setInput(array $input)
    {
        $this->input = $input;

        return $this;
    }

    /**
     * Get Input
     *
     * @return array Input
     */
    public function getInput()
    {
        return $this->input;
    }
}