Call to a member function roles() on null in Laravel - php

Question

I'm getting started on mastering Laravel. I'm trying to create a system where the superuser can edit the roles of all the users. It has been going well until now.
My front end looks like this:
#section('content')
<table>
<thead>
<th>Voornaam</th>
<th>Achternaam</th>
<th>E-mail</th>
<th>User</th>
<th>Admin</th>
<th>Superuser</th>
</thead>
</table>
<tbody>
#foreach($users as $user)
<tr>
<form action="{{ route('superuser.assign') }}" method="post">
<td>{{$user->first_name}}</td>
<td>{{$user->name}}</td>
<td>{{$user->email}}</td>
<td><input type="checkbox" {{ $user->hasRole('User') ? 'checked' : '' }} name="role_user"></td>
<td><input type="checkbox" {{ $user->hasRole('Admin') ? 'checked' : '' }} name="role_admin"></td>
<td><input type="checkbox" {{ $user->hasRole('Superuser') ? 'checked' : '' }} name="role_superuser"></td>
{{ csrf_field() }}
<td><button type="submit">Assign Roles</button></td>
</form>
</tr>
#endforeach
</tbody>
#endsection
The problem is that when I try to assign a role to an existing user through my front end, it throws the error
Call to a member function roles() on null
I have a UserController that looks like this:
public function postAssignRoles(Request $request)
{
$user = User::where('email', $request['email'])->first();
$user->roles()->detach();
if ($request['role_user'])
{
$user->roles()->attach(Role::where('name', 'User')->first());
}
if ($request['role_admin'])
{
$user->roles()->attach(Role::where('name', 'Admin')->first());
}
if ($request['role_superuser'])
{
$user->roles()->attach(Role::where('name', 'Superuser')->first());
}
return redirect()->back();
}
}
And my User class contains the following:
public function roles()
{
return $this->belongsToMany('App\Role', 'user_role', 'user_id', 'role_id');
}
public function hasAnyRole($roles)
{
if (is_array($roles))
{
foreach ($roles as $role)
{
if ($this -> hasRole($role))
{
return true;
}
}
}
else
{
if ($this -> hasRole($roles))
{
return true;
}
}
return false;
}
public function hasRole($role)
{
if ($this->roles()->where('name', $role)->first())
{
return true;
}
return false;
}
}
I also set up this in my middleware
public function handle($request, Closure $next)
{
if ($request->user() === null)
{
return response("U bent niet bevoegd om deze actie uit te voeren.", 401);
}
$actions = $request->route()->getAction();
$roles = isset($actions['roles']) ? $actions['roles'] : null;
if ($request->user()->hasAnyRole($roles) || !$roles)
{
return $next($request);
}
return response("U bent niet bevoegd om deze actie uit te voeren.", 401);
}
and added this in the Kernel
'roles' => \App\Http\Middleware\CheckRole::class
I think the problem is that for one reason or another $user = User::where('email', $request['email'])->first(); returns null. I tried get()instead of first(), but then I get a Method Illuminate\Database\Eloquent\Collection::roles does not exist.error.
I'm sorry for the many code snippets, but I've been struggling with this for the past 8 hours and really don't know where to search the problem anymore. Please someone help me before I go cry myself to sleep in the corner of my room and never touch Laravel again.

Answer 1

You are right that calling first() on your query returns null, hence the reason why you get that error.
So what you can use to prevent calling roles() on null object is to use firstOrFail() method which will throw a ModelNotFoundException which you can catch using a try catch block and handle it gracefully.
And as I can see in your view you are not sending the value of the email in your form, so you should put the email in a hidden input:
<td>
<input type="hidden" name="email" value="{{$user->email}}" />
{{$user->email}}"
</td>
not having this is why you get null result.

Answer 2

You must check if the values you are intending to pass are set, You can do so with isset
example #isset('$user->hasRole('User')');