Laravel 5.7:我向构造函数中注入了bunch on类，但constructor \Csv\Reader是唯一一个不能工作的

Question

我有一些artisan命令来执行一些CLI逻辑。

class SyncFooCommand extends AbstractBaseSyncCommand
class SyncBarCommand extends AbstractBaseSyncCommand
class SyncBazCommand extends AbstractBaseSyncCommand

每个artisan命令都会扩展abstract class AbstractBaseSyncCommand extends Command implements SyncInterface。

多亏了这一点，我可以在抽象的父类中加入一些共享的逻辑。

我注入了Carbon或FileSystem，两者都在孩子们的班级里工作得像个魔法师。

<?php

namespace App\Console\Commands\Sync;

use Carbon\Carbon;
use Illuminate\Console\Command;
use Illuminate\Contracts\Filesystem\Factory as Filesystem;
use League\Csv\Reader;

abstract class AbstractBaseSyncCommand extends Command implements SyncInterface
{
    protected $carbon;
    protected $fileSystem;
    protected $reader;

    public function __construct(
        Carbon $carbon,
        FileSystem $fileSystem,
        Reader $reader
    ) {
        parent::__construct();

        $this->carbon = $carbon; // works like a charm
        $this->fileSystem = $fileSystem; // works like a charm
        $this->reader = $reader; // fails, why?
    }
}

在SyncWhateverCommand中，我可以很容易地调用和使用$this->carbon或$this->fileSystem，但只要它命中$this->reader，我就会得到：

   Illuminate\Contracts\Container\BindingResolutionException  : Target [League\Csv\Reader] is not instantiable while building [App\Console\Commands\Sync\SyncFooCommand].

  at /home/vagrant/code/foo/vendor/laravel/framework/src/Illuminate/Container/Container.php:945
    941|         } else {
    942|             $message = "Target [$concrete] is not instantiable.";
    943|         }
    944|
  > 945|         throw new BindingResolutionException($message);
    946|     }
    947|
    948|     /**
    949|      * Throw an exception for an unresolvable primitive.

怎么了？The installation很简单，不需要做任何绑定。我遗漏了什么？

总结一下：

$csv = $this->reader->createFromPath($path, 'r'); // fails, but I want to use it this way

$csv = Reader::createFromPath($path, 'r'); // works but I don't want facades because they look ugly

Answer 1

也许你的应用程序应该知道如何检索它？喜欢

$this->app->bind('SomeAbstraction', function ($app) {
    return new Implementation();
});