Laravel: Check if all values exists in a relation - php

Question

I have a many to many relationship between User and Role models and want to check if a user has any role of a given list.
So I typed on model:
public function hasAnyRoles(array $roles) {
return $this->roles()->whereIn('name', $roles)->exists();
}
And on UserController:
// User has only "manager" role.
$user->hasAnyRoles(['admin', 'manager']) // true
The problem is that in some parts I need to verify if the user has all roles of the given list. For example:
// User has only "manager" role.
$user->hasRoles(['admin', 'manager']) // false
I wrote it in a "lazy" mode, that generates n + 1 queries:
public function hasRolesLazy($roles) {
return array_reduce($roles, function ($initial, $role) {
return $this->roles()->where('name', $role)->exists();
}, false);
}
How hasRoles(array $roles) method must be constructed to execute only one query in database? I'm a newbie in SQL so I can't figure out many solutions for this.

Answer 1

Try this:
public function hasAnyRoles(array $roles) {
return $this->whereHas('roles', function ($query) use ($roles) {
return $query->whereIn('name', $roles);
})->isNotEmpty();
}

Answer 2

My recommendation would be, to load all of the roles for the user once using the relationship. When you load a relationship by calling it like a property, Laravel will cache it under the hood, so it doesn't repeat any queries. You can then simply use the loaded roles to implement your two methods:
public function hasAnyRoles(array $roles)
{
// When you call $this->roles, the relationship is cached. Run through
// each of the user's roles.
foreach ($this->roles as $role) {
// If the user's role we're looking at is in the provided $roles
// array, then the user has at least one of them. Return true.
if (in_array($role->name, $roles) {
return true;
}
}
// If we get here, the user does not have any of the required roles.
// Return false.
return false;
}
and the second method:
public function hasRoles(array $roles)
{
// Run through each of the roles provided, that the user MUST have
foreach ($roles as $role) {
// Call the $this->roles relationship, which will return a collection
// and be cached. Find the first role that has the name of the role
// we're looking at.
$found = $this->roles->first(function ($r) use ($role) {
return $r->name == $role;
});
// If a role could not be found in the user's roles that matches the
// one we're looking, then the user does not have the role, return
// false
if (!$found) {
return false;
}
}
// If we get here, the user has all of the roles provided to the method
return true;
}
There are of course many different ways to implement these methods, particularly methods found in the Collection class will help you, but the point is that using $this->roles results in only a single query.