Laravel resource policy always false - php

Question

I'm trying to allow user to view their own profile in Laravel 5.4.
UserPolicy.php
public function view(User $authUser, $user)
{
return true;
}
registered policy in AuthServiceProvider.php
protected $policies = [
App\Task::class => App\Policies\TaskPolicy::class,
App\User::class => App\Policies\UserPolicy::class
];
Routes
Route::group(['middleware' => 'auth'], function() {
Route::resource('user', 'UserController');
} );
Blade template
#can ( 'view', $user )
// yes
#else
// no
#endcan
UserController.php
public function profile()
{
return $this->show(Auth::user()->id);
}
public function show($id)
{
$user = User::find($id);
return view('user.show', array( 'user'=>$user,'data'=>$this->data ) );
}
The return is always 'false'. Same for calling policy form the controller. Where do I go wrong?

Answer 1

Answering my own question feels weird, but I hate it when I come across questions without followups.
So after double checking It turned out that if I remove authorizeResource from the constructor:
public function __construct()
{
$this->authorizeResource(User::class);
}
and check for authorization in the controller function:
$this->authorize('view',$user);
everything works.
I must've missed this part when I added $user as a parameter in the policy function. So the user to be viewed is never passed in the authorizeResource method.
Thanks everyone for taking your time to help me.

Answer 2

When you add
public function __construct()
{
$this->authorizeResource(User::class);
}
to your Controller, you have to edit all your function signatures to match it to the class e.g. your show signature has to change from public function show($id)
to public function show(User $user)
After that it should work

Answer 3

Just a different approach here to users viewing their own profile.
First, I will create a route for that
Route::group(['middleware' => 'auth'], function() {
Route::get('profile', 'UserController#profile');
});
Then in the profile function I do
public function profile()
{
$user = Auth::user();
return view('profile', compact('user'));
}
This way, user automatically only views their own profile.
Now, if you want to allow some users to view others' profiles, then you can use Policy. Why? Because I think user should ALWAYS be able to view their own profile. But not all users should view other users profiles.

Answer 4

Solution:
Change the second parameter from #can( 'view', $user ) to #can( 'view', $subject ) and it will work find.
Why:
Because you're doing it the wrong way.
public function view(User $user, $subject){
return true;
}
Just look carefully the policy view method, first parameter is authenticated user or current user and second parameter is $subject, Since policies organize authorization logic around models.
Policies are classes that organize authorization logic around a
particular model or resource. For example, if your application is a
blog, you may have a Post model and a corresponding PostPolicy to
authorize user actions such as creating or updating posts.
if you want to go further deep inside it.
https://github.com/laravel/framework/blob/5.3/src/Illuminate/Auth/Access/Gate.php#L353
/**
* Resolve the callback for a policy check.
*
* #param \Illuminate\Contracts\Auth\Authenticatable $user
* #param string $ability
* #param array $arguments
* #return callable
*/
protected function resolvePolicyCallback($user, $ability, array $arguments)
{
return function () use ($user, $ability, $arguments) {
$instance = $this->getPolicyFor($arguments[0]);
// If we receive a non-null result from the before method, we will return it
// as the final result. This will allow developers to override the checks
// in the policy to return a result for all rules defined in the class.
if (method_exists($instance, 'before')) {
if (! is_null($result = $instance->before($user, $ability, ...$arguments))) {
return $result;
}
}
if (strpos($ability, '-') !== false) {
$ability = Str::camel($ability);
}
// If the first argument is a string, that means they are passing a class name
// to the policy. We will remove the first argument from this argument list
// because the policy already knows what type of models it can authorize.
if (isset($arguments[0]) && is_string($arguments[0])) {
array_shift($arguments);
}
if (! is_callable([$instance, $ability])) {
return false;
}
return $instance->{$ability}($user, ...$arguments);
};
}
See the last line where it is calling the method with $user and $argument( in our case Model ) is passed.
Laravel Docs for Authorization/Policies

Answer 5

It's possible to escape one or more policies methods using options parameter at authorizeResource with except:
public function __construct()
{
$this->authorizeResource(User::class, 'user', ['except' => ['view']]);
}
This should be on Laravel's documentation, but it isn't. I discovered this just guessing. I think this way it is a better approach thus, by removing authorizeResource method in the construct, it would be necessary to implement the authorization method for each resource action in order to protect the controller.