没有依赖项注入的Laravel Facade类型错误

Question

I am trying to access a function from anywhere in my app. But I get the following error:

Type error: Argument 1 passed to App\\Helpers\\AwsAutoscale::__construct() must be an instance of Aws\\AutoScaling\\AutoScalingClient, none given, called in /home/vagrant/Site/app/Providers/AwsAutoscaleProvider.php on line 31

My code is:

App/Helpers/AwsAutoscale.php

<?php

namespace App\Helpers;

use Aws\AutoScaling\AutoScalingClient;

class AwsAutoscale
{

    private $awsClient;

    public function __construct(AutoScalingClient $awsClient)
    {
        $this->awsClient = $awsClient;
    }

    public function groupStats()
    {
        $result = $this->awsClient->describeAutoScalingGroups();

        return collect([
            'desired' => $result['AutoScalingGroups'][0]['DesiredCapacity'],
            'min' => $result['AutoScalingGroups'][0]['MinSize'],
            'max' => $result['AutoScalingGroups'][0]['MaxSize'],
            'current' => count($result['AutoScalingGroups'][0]['Instances'])
        ]);
    }

}

App/Providers/AutoScalingClientProvider.php

<?php

namespace App\Providers;

use Aws\AutoScaling\AutoScalingClient;
use Illuminate\Support\ServiceProvider;

class AutoScalingClientProvider extends ServiceProvider
{
    /**
     * Register the application services.
     *
     * @return void
     */
    public function register()
    {
        $this->app->bind(AutoScalingClient::class, function () {
            return new AutoScalingClient([
                'AutoScalingGroupName' => config('aws.auto_scaling_client.name'),
                'region' => config('aws.auto_scaling_client.region'),
                'version' => config('aws.auto_scaling_client.version')
            ]);
        });

    }

}

App/Providers/AwsAutoScaleProvider.php

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;

class AwsAutoscaleProvider extends ServiceProvider
{
    /**
     * Bootstrap the application services.
     *
     * @return void
     */
    public function boot()
    {
        //
    }

    /**
     * Register the application services.
     *
     * @return void
     */
    public function register()
    {
        //
        $this->app->bind('autoscale', function()

        {

            return new \App\Helpers\AwsAutoscale;

        });
    }
}

config/app.php:

'providers' => [
    ...
    App\Providers\AwsAutoscaleProvider::class
    ...

'aliases' => [
    ...
    'autoscale'=> App\Facades\AutoscaleFacade::class,
    ...

Code in controller:

return autoscale::groupStats();

Calling this results in the error:

Type error: Argument 1 passed to App\\Helpers\\AwsAutoscale::__construct() must be an instance of Aws\\AutoScaling\\AutoScalingClient, none given, called in /home/vagrant/Site/app/Providers/AwsAutoscaleProvider.php on line 31

Answer 1

Let say you have this AwsAutoscale helper saved within App/Helpers/AwsAutoscale.php :

<?php

namespace App\Helpers;

use Aws\AutoScaling\AutoScalingClient;

class AwsAutoscale
{
    private $awsClient;

    public function __construct(AutoScalingClient $awsClient)
    {
        $this->awsClient = $awsClient;
    }

    public function groupStats()
    {
        $result = $this->awsClient->describeAutoScalingGroups();

        return collect([
            'desired' => $result['AutoScalingGroups'][0]['DesiredCapacity'],
            'min' => $result['AutoScalingGroups'][0]['MinSize'],
            'max' => $result['AutoScalingGroups'][0]['MaxSize'],
            'current' => count($result['AutoScalingGroups'][0]['Instances']),
        ]);
    }
}

And you want this AwsAutoscale class instance to be accessible through Facade . The first step is to register it within the service provider . Let's put it together within the App/Providers/AutoScalingClientProvider.php file:

<?php

namespace App\Providers;

use App\Helpers\AwsAutoscale;
use Aws\AutoScaling\AutoScalingClient;
use Illuminate\Support\ServiceProvider;

class AutoScalingClientProvider extends ServiceProvider
{
    public function register()
    {
        // Bind the AutoScalingClient.
        $this->app->bind(AutoScalingClient::class, function () {
            return new AutoScalingClient([
                'AutoScalingGroupName' => config('aws.auto_scaling_client.name'),
                'region' => config('aws.auto_scaling_client.region'),
                'version' => config('aws.auto_scaling_client.version')
            ]);
        });

        // Bind the AwsAutoscale helper.
        $this->app->singleton('autoscale', function ($app) {
            // You need to manually inject the dependency, which is the AutoScalingClient instance
            return new AwsAutoscale($app->make(AutoScalingClient::class));
        });
    }
}

You can delete the App/Providers/AwsAutoScaleProvider.php file, since we already bind the AwsAutoscale on AutoScalingClientProvider.php .

If you want to access the AwsAutoscale through facade, you'll need to create a facade class for this. Let's say we put it on App\\Facades\\AutoscaleFacade.php :

<?php

namespace App\Facades;

use Illuminate\Support\Facades\Facade;

class AutoscaleFacade extends Facade
{
    protected static function getFacadeAccessor()
    {
        // Return the key we use on service provider to bind AwsAutoclass instance
        return 'autoscale';
    }
}

Next, we need to register both the service provider and the facade class on the config\\app.php :

<?php

return [
    ...
    'providers' => [
        ...
        App\Providers\AutoScalingClientProvider::class,
    ],
    'aliases' => [
        ...
        'Autoscale' => App\Facades\AutoscaleFacade::class,
    ],
];

Now you can easily access the AwsAutoscale instance using the registered alias like so:

Route::get('/foo', function () {
    // Access it with the Autoscale facade class not AwsAutoscale
    dd(\Autoscale::groupStats());
});

Hope this gives you some ideas.