What is the difference between Laravel Gate and Policies

In Laravel, both gates and policies are used for authorization and access control within your application. They help you determine whether a user is allowed to perform a certain action on a particular resource. However, they serve slightly different purposes in different scenarios. Depending on the scenario it's your call what to choose.

Laravel Gates

Gates are a more general way of defining authorization logic. They allow you to define arbitrary authorization checks based on various conditions. You typically define gates in the AuthServiceProvider class. Gates are usually used when you need to perform custom authorization checks that don't necessarily relate to a specific model or resource.

For example, you might define a gate to check if a user has administrative privileges.

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

and the check will become something like this,

if (Gate::allows('admin')) {
    // User is an admin, do something cool.
}

Laravel Policies

Policies, on the other hand, are more focused on authorization checks related to specific models. They are often used to centralize and encapsulate authorization logic for a particular model class. You can create a policy by using the following command.

php artisan make:policy PostPolicy --model=Post

Policies consist of methods that represent different authorization actions you might want to perform on a model. The policy created from the above command will look something like this.

<?php

namespace App\Policies;

use App\Models\Post;
use App\Models\User;
use Illuminate\Auth\Access\Response;

class PostPolicy
{
    /**
     * Determine whether the user can view any models.
     */
    public function viewAny(User $user): bool
    {
        //
    }

    /**
     * Determine whether the user can view the model.
     */
    public function view(User $user, Post $post): bool
    {
        //
    }

    /**
     * Determine whether the user can create models.
     */
    public function create(User $user): bool
    {
        //
    }

    /**
     * Determine whether the user can update the model.
     */
    public function update(User $user, Post $post): bool
    {
        //
    }

    /**
     * Determine whether the user can delete the model.
     */
    public function delete(User $user, Post $post): bool
    {
        //
    }

    /**
     * Determine whether the user can restore the model.
     */
    public function restore(User $user, Post $post): bool
    {
        //
    }

    /**
     * Determine whether the user can permanently delete the model.
     */
    public function forceDelete(User $user, Post $post): bool
    {
        //
    }
}

lets for the sake of example, update the update method something like this.

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

Then, in your code, you can authorize actions using a policy like this,

if ($user->can('update', $post)) {
    // User is authorized to update the post
}

Comparison

In summary, the main difference between gates and policies lies in their scope and purpose:

• Gates are more versatile and suitable for creating custom authorization logic that doesn't directly relate to specific models. They are defined globally and can be used for various authorization checks across your application.
• Policies are tailored to authorization checks related to specific model instances. They provide a structured way to encapsulate authorization logic for a model and its actions.

Both gates and policies have their place in Laravel's authorization system, and which one to use depends on the context of your application and the complexity of your authorization requirements, and most importantly it depends on You.