FOS bundle - How to select users with a specific role?

Just add this in your UserRepository or replace $this->_entityName by YourUserBundle:User:

/**
 * @param string $role
 *
 * @return array
 */
public function findByRole($role)
{
    $qb = $this->_em->createQueryBuilder();
    $qb->select('u')
        ->from($this->_entityName, 'u')
        ->where('u.roles LIKE :roles')
        ->setParameter('roles', '%"'.$role.'"%');

    return $qb->getQuery()->getResult();
}

If you are using FOSUser Groups you should use:

/**
 * @param string $role
 *
 * @return array
 */
public function findByRole($role)
{
    $qb = $this->_em->createQueryBuilder();
    $qb->select('u')
        ->from($this->_entityName, 'u')
        ->leftJoin('u.groups', 'g')
        ->where($qb->expr()->orX(
            $qb->expr()->like('u.roles', ':roles'),
            $qb->expr()->like('g.roles', ':roles')
        ))
        ->setParameter('roles', '%"'.$role.'"%');

    return $qb->getQuery()->getResult();
}

Well, if there is no better solution, I think I will go to a DQL query:

$query = $this->getDoctrine()->getEntityManager()
            ->createQuery(
                'SELECT u FROM MyBundle:User u WHERE u.roles LIKE :role'
            )->setParameter('role', '%"ROLE_MY_ADMIN"%');

$users = $query->getResult();

If you have this requirement and your user list will be extensive, you will have problems with performance. I think you should not store the roles in a field as a serialized array. You should create an entity roles and many to many relationship with the users table.

As @Tirithen states, the problem is that you will not get the users that have an implicit role due to role hierarchy. But there is a way to work around that!

The Symfony security component provides a service that gives us all child roles for a specific parent roles. We can create a service that does almost the same thing, only it gives us all parent roles for a given child role.

Create a new service:

namespace Foo\BarBundle\Role;

use Symfony\Component\Security\Core\Role\RoleHierarchy;
use Symfony\Component\Security\Core\Role\Role;

/**
 * ReversedRoleHierarchy defines a reversed role hierarchy.
 */
class ReversedRoleHierarchy extends RoleHierarchy
{
    /**
     * Constructor.
     *
     * @param array $hierarchy An array defining the hierarchy
     */
    public function __construct(array $hierarchy)
    {
        // Reverse the role hierarchy.
        $reversed = [];
        foreach ($hierarchy as $main => $roles) {
            foreach ($roles as $role) {
                $reversed[$role][] = $main;
            }
        }

        // Use the original algorithm to build the role map.
        parent::__construct($reversed);
    }

    /**
     * Helper function to get an array of strings
     *
     * @param array $roleNames An array of string role names
     *
     * @return array An array of string role names
     */
    public function getParentRoles(array $roleNames)
    {
        $roles = [];
        foreach ($roleNames as $roleName) {
            $roles[] = new Role($roleName);
        }

        $results = [];
        foreach ($this->getReachableRoles($roles) as $parent) {
            $results[] = $parent->getRole();
        }

        return $results;
    }
}

Define your service for instance in yaml and inject the role hierarchy into it:

# Provide a service that gives you all parent roles for a given role.
foo.bar.reversed_role_hierarchy:
    class: Foo\BarBundle\Role\ReversedRoleHierarchy
    arguments: ["%security.role_hierarchy.roles%"]

Now you are ready to use the class in your own service. By calling $injectedService->getParentRoles(['ROLE_YOUR_ROLE']); you will get an array containing all parent roles that will lead to the 'ROLE_YOUR_ROLE' permission. Query for users that have one or more of those roles... profit!

For instance, when you use MongoDB you can add a method to your user document repository:

/**
 * Find all users with a specific role.
 */
public function fetchByRoles($roles = [])
{
    return $this->createQueryBuilder('u')
        ->field('roles')->in($roles)
        ->sort('email', 'asc');
}

I'm not into Doctrine ORM but I'm sure it won't be so different.