What are Gates and Policies in Laravel

Gates

Gates are simple, closure-based authorization rules that can be used throughout your application. They are typically defined in the `AuthServiceProvider` using the `Gate` facade. Gates receive a user instance as their first argument and may optionally receive additional arguments such as an Eloquent model[1][4].

Here's an example of defining a gate:

php
Gate::define('edit-settings', function ($user) {
    return $user->isAdmin;
});

You can then use the `allows` or `denies` methods of the `Gate` facade to check if the current user is authorized to perform an action[5]:

php
if (Gate::allows('edit-settings')) {
    // The user can edit the settings
}

Gates are best suited for simple authorization scenarios that are not tied to a specific model or resource[2].

Policies

Policies are classes that encapsulate authorization logic for a specific model or resource. They are defined as classes in the `App\Policies` namespace and typically contain methods for each action that needs to be authorized, such as `view`, `create`, `update`, or `delete`[1][4].

Here's an example of a policy for a `Post` model:

php
class PostPolicy
{
    public function view(User $user, Post $post)
    {
        //
    }

    public function create(User $user)
    {
        //
        return $user->isAdmin;
    }

    public function update(User $user, Post $post)
    {
        return $user->id == $post->user_id;
    }

    public function delete(User $user, Post $post)
    {
        //
    }
}

Policies are registered in the `AuthServiceProvider` and can be automatically discovered based on naming conventions[4]. You can then use the `authorize` method in your controllers to check if the current user is authorized to perform an action on a specific model instance[1].

php
public function update(Request $request, Post $post)
{
    $this->authorize('update', $post);

    // The user can update the post
}

Policies are best suited for more complex authorization scenarios that are specific to a particular model or resource[2].

In summary, Gates provide a simple, flexible way to define authorization rules, while Policies offer a more structured approach for managing authorization logic for specific models or resources. Most applications will use a combination of both Gates and Policies to implement their authorization system[4].