How to define findOneBy($criteria) function? - symfony

Question

I am very new to Symfony2, designing a simple login system. The userclass,
router, controlerclass everything is working fine. I am stuck to
userRepository class.
My controller part is:
public function loginProcessAction(Request $request){
if($request->getMethod() == "POST") {
$username = $request->get('username');
$password = $request->get('password');
$em= $this->getDoctrine()->getEntityManager();
$repository = $em->getRepository("LoginLoginBundle:Student");
$user = $repository->findOneBy(array('username'=>$username,
'password'=>$password));
if($user){
return $this->render('loginSuccess twig page') ;
}
else{
return $this->render('error twig page') ;
}
} else{
return $this->render("login error page");
}
}
How to define findOneBy(username, password) function in reopository class.

Answer 1

This is not the best way to handle authentication when using Symfony2. Take a look at the Security component integrated with Symfony2.
So check How Security Works: Authentication and Authorization part of the security documentation, all you need to implement/configure is Firewalls to handle Authentication and
Access Controls for Authorization.
But ...
Here's an answer to the common question: How to a define findOneBy(parameter1, parameter2) function for a given repository class?
First, map your entity to the appropriate repository as follow,
/*
* #ORM\Entity(repositoryClass="YourNamespace\YourBundle\Entity\yourRepository")
*/
class YourEntity
{
// ...
}
You should then add the mapped repository class and implement a findOneBy(parameter1, parameter2) method.
You can then access this class within your controller as follow,
$em= $this->getDoctrine()->getManager();
$yourEntityInstance = $em->getRepository("yourNamespaceYourBundle:YourEntity")
->findOneBy($parameter1, $parameter2);