Symfony, Doctrine update not working as expected - php

Question

Hey All I have this wired error that I cannot overcome. I am using Symfony Framweork and Doctrine for my DB interaction. I am trying to develop a simple CRUD API to grasp some of the concepts.
The actual problem is when I try to update an item in my DB it only works if the ID of the item is inside the DB else I get this error:
Error: Call to a member function setTitle() on a non-object
Have a look at my Repository:
<?php
namespace BooksApi\BookBundle\Repositories;
use Doctrine\ORM\EntityManager;
use Doctrine\ORM\Query\QueryException;
class UpdateBookRepository
{
/**
* #var EntityManager
*/
public $em;
/**
* #param EntityManager $entityManager
*/
public function __construct(
EntityManager $entityManager
){
$this->em = $entityManager;
}
public function updateBook($id, $update)
{
try {
$book = $this->em->getRepository('BooksApiBookBundle:BooksEntity')
->find($id);
$book->setTitle($update);
$this->em->flush();
} catch (\Exception $em) {
throw new QueryException('003', 502);
}
return $book;
}
}
And My factory:
<?php
namespace BooksApi\BookBundle\Repositories;
use Doctrine\ORM\EntityManager;
use Doctrine\ORM\Query\QueryException;
class UpdateBookRepository
{
/**
* #var EntityManager
*/
public $em;
/**
* #param EntityManager $entityManager
*/
public function __construct(
EntityManager $entityManager
){
$this->em = $entityManager;
}
public function updateBook($id, $update)
{
$book = $this->em->getRepository('BooksApiBookBundle:BooksEntity')
->find($id);
if ($book)
{
try {
$book->setTitle($update);
$this->em->flush();
} catch (\Exception $em) {
throw new QueryException('003', 502);
}
return $book;
} else {
return false;
}
}
}
The factory handles the response true or false, So in event where I will try to update an Item thats ID is not in DB the factory should respond with false, 'Unable to Update Book' instead i get the above error, Any idea why guys..?

Answer 1

#Tomazi, you can avoid error by checking if your object exists before calling "setTitle" method.
public function updateBook($id, $update)
{
$book = $this->em->getRepository('BooksApiBookBundle:BooksEntity')->find($id);
if ($book) {
$book->setTitle($update);
$this->em->flush();
return $book;
}
return null;
}

Answer 2

Make sure that $book object is not empty before proceeding with the code. The error indicates that $book is null/empty.
Also, persist your object before using flush.
$this->em->persist($book);
$this->em->flush();