Laravel 5.7 Gate::allows 非静态方法 Illuminate\\Auth\\Access\\Gate::allows() 不应静态调用

Question

I got this error in Laravel 5.7 when using Gate::allows in my formRequest class.

I was using this: use Illuminate\\Auth\\Access\\Gate; and it didn't work,

so I replaced it with this: use Illuminate\\Support\\Facades\\Gate and it worked.

I really need to know why the first didn't work and what is the difference between the two. I have tried looking up stuff but I need a more direct and concise explanation. Any help or pointer will be highly appreciated.

Answer 1

In a Laravel application, a facade is a class that provides access to an object from the container. The machinery that makes this work is in the Facade class. Laravel's facades, and any custom facades you create, will extend the base Illuminate\\Support\\Facades\\Facade class.

The Facade base class makes use of the __callStatic() magic-method to defer calls from your facade to an object resolved from the container. In the example below, a call is made to the Laravel cache system. By glancing at this code, one might assume that the static method get is being called on the Cache class:

<?php

namespace App\Http\Controllers;

use App\Http\Controllers\Controller;
use Illuminate\Support\Facades\Cache;

class UserController extends Controller
{
    /**
     * Show the profile for the given user.
     *
     * @param  int  $id
     * @return Response
     */
    public function showProfile($id)
    {
        $user = Cache::get('user:'.$id);

        return view('profile', ['user' => $user]);
    }
}

Notice that near the top of the file we are "importing" the Cache facade. This facade serves as a proxy to accessing the underlying implementation of the Illuminate\\Contracts\\Cache\\Factory interface. Any calls we make using the facade will be passed to the underlying instance of Laravel's cache service.

If we look at that Illuminate\\Support\\Facades\\Cache class, you'll see that there is no static method get:

class Cache extends Facade {
    /**
     * Get the registered name of the component.
     *
     * @return string
     */
    protected static function getFacadeAccessor() { return 'cache'; } }

Instead, the Cache facade extends the base Facade class and defines the method getFacadeAccessor(). This method's job is to return the name of a service container binding. When a user references any static method on the Cache facade, Laravel resolves the cache binding from the service container and runs the requested method (in this case, get) against that object.

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