Symfony entity validation verify foreign key exists - symfony

Question

I would like to be able to use entity validator constraints to verify if the foreign key book_id is valid, please see below:
Book.php
/**
* Book
*
* #ORM\Table("book")
* #ORM\Entity
* #ORM\Entity(repositoryClass="AppBundle\Repository\BookRepository")
*/
class Book
{
/**
* #var integer
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var string
* #ORM\Column(name="name", type="string")
* #Assert\Length(
* max = 250,
* maxMessage = "Name cannot be longer than {{ limit }} characters",
* groups={"create","update"}
* )
*/
private $name;
/**
* #ORM\OneToOne(targetEntity="Loan", mappedBy="book", fetch="LAZY")
*/
protected $loan;
}
Loan.php
/**
* Loan
*
* #ORM\Table("loan")
* #ORM\Entity
* #ORM\Entity(repositoryClass="AppBundle\Repository\LoanRepository")
*/
class Loan
{
/**
* #var integer
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var integer
* #ORM\Column(name="book_id", type="integer")
*/
protected $book_id;
/**
* #var string
* #ORM\Column(name="name", type="string")
* #Assert\Length(
* max = 500,
* maxMessage = "Person cannot be longer than {{ limit }} characters",
* groups={"create","update"}
* )
*/
private $person;
/**
* #ORM\OneToOne(targetEntity="Book", inversedBy="loan")
* #ORM\JoinColumn(name="book_id", referencedColumnName="id")
*/
protected $book;
}
Here is how I am currently validating the loan entity
$loan = new Loan();
$loan->setPerson($person);
$loan->setBookId($id);
/** #var ConstraintViolation $error */
foreach ($this->get('validator')->validate($loan,null,['create'])->getIterator() as $index => $error) {
$errorMessages[] = $error->getMessage();
}
I figured maybe I can add a custom validator like this to the loan entity:
/**
* #Assert\IsTrue(message = "The book does not exist")
* #return bool
*/
public function isBookLegal(BookRepository $bookRepository)
{
return !$bookRepository->fetchById($this->book_id);
}
But I end up with the follow exception:
Type error: Too few arguments to function
AppBundle\Entity\Loan::isBookLegal(), 0 passed and exactly 1 expected

Answer 1

First of all, you should not have both $book_id and $book in your Loan entity. You should remove $book_id, which is enough for your entity relationship.
Then, all you need to do is add an #Assert\NotBlank() on $book:
use Symfony\Component\Validator\Constraints as Assert;
...
/**
* #ORM\OneToOne(targetEntity="Book", inversedBy="loan")
* #ORM\JoinColumn(name="book_id", referencedColumnName="id")
* #Assert\NotBlank()
*/
protected $book;
I'm not sure what code you are using to get all of your loans, but as Edwin states that's not really good form. You want want something more like:
foreach ($loans as $loan) {
$errors = $this->get('validator')->validate($loan);
// do something here if there is an error
}
The assertion function you wrote isn't going to work because you can't pass in a value to your isBookLegal() function there, nor can you ever use the database connection/repository from within your Entity class.
I'm not really sure what you are trying to accomplish without greater context here. Doctrine is already going to validate your $book member because of your #ORM\OneToOne annotation in the first place. You don't have to perform any additional validation. I'm guessing you are trying to pass in a value directly to $book_id, which is incorrect. You should only be passing already-valid $book entities to your Loan class, via $loan->setBook(Book $book);