Laravel 5 Model Factories Null Error

Question

当我尝试仅将模型工厂用于我的Message模型时，这是我收到的错误。其他模型工厂工作得很好，我已经将它跟踪到laravel的FactoryBuilder中的applyStates方法，它实际上是空的，我只是不确定原因。我已经定义了模型类，我创建了表，我的方法中为消息添加种子数据的代码正在工作，但是在插入第一条记录后抛出此错误，这样就不会为我添加一堆种子数据。< / p>

[2016-12-23 20:24:04] local.ERROR: Symfony\Component\Debug\Exception\FatalThrowableError: Type error: Argument 1 passed to Illuminate\Database\Eloquent\FactoryBuilder::applyStates() must be of the type array, null given, called in /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Database/Eloquent/FactoryBuilder.php on line 168 in /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Database/Eloquent/FactoryBuilder.php:180
Stack trace:

- 0 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Database/Eloquent/FactoryBuilder.php(168): Illuminate\Database\Eloquent\FactoryBuilder->applyStates(NULL, Array)
- 1  /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Model.php(2282): Illuminate\Database\Eloquent\FactoryBuilder->Illuminate\Database\Eloquent\{closure}()
- 2 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Database/Eloquent/FactoryBuilder.php(170): Illuminate\Database\Eloquent\Model::unguarded(Object(Closure))
- 3 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Database/Eloquent/FactoryBuilder.php(143): Illuminate\Database\Eloquent\FactoryBuilder->makeInstance(Array)
- 4 [internal function]: Illuminate\Database\Eloquent\FactoryBuilder->Illuminate\Database\Eloquent\{closure}(1)
- 5 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Database/Eloquent/FactoryBuilder.php(144): array_map(Object(Closure), Array)
- 6 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Database/Eloquent/FactoryBuilder.php(113): Illuminate\Database\Eloquent\FactoryBuilder->make(Array)
- 7 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/database/seeds/MessagesTableSeeder.php(15): Illuminate\Database\Eloquent\FactoryBuilder->create()
- 8 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Database/Console/Seeds/SeedCommand.php(63): MessagesTableSeeder->run()
- 9 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Model.php(2288): Illuminate\Database\Console\Seeds\SeedCommand->Illuminate\Database\Console\Seeds\{closure}()
- 10 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Database/Console/Seeds/SeedCommand.php(64): Illuminate\Database\Eloquent\Model::unguarded(Object(Closure))
- 11 [internal function]: Illuminate\Database\Console\Seeds\SeedCommand->fire()
- 12 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Container/Container.php(508): call_user_func_array(Array, Array)
- 13 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Console/Command.php(169): Illuminate\Container\Container->call(Array)
- 14 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/symfony/console/Command/Command.php(254): Illuminate\Console\Command->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
- 15 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Console/Command.php(155): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
- 16 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/symfony/console/Application.php(821): Illuminate\Console\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
- 17 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/symfony/console/Application.php(187): Symfony\Component\Console\Application->doRunCommand(Object(Illuminate\Database\Console\Seeds\SeedCommand), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
- 18 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/symfony/console/Application.php(118): Symfony\Component\Console\Application->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
- 19 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php(121): Symfony\Component\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
- 20 /Users/jcrawford/Dropbox/Work/RYNO/htdocs/artisan(35): Illuminate\Foundation\Console\Kernel->handle(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
- 21 {main}

//模型工厂

$factory->define(Message::class, function(Faker\Generator $faker) {
$userIds = User::all()->pluck('id')->toArray();
$postIds = Post::all()->pluck('id')->toArray();

$post = Post::find($faker->randomElement($postIds));

$user1 = User::find($faker->randomElement($userIds));
$user2 = User::find($faker->randomElement($userIds));

$message1 = new Message([
    'post_id' => $post->id,
    'to_user_id' => $user1->id,
    'from_user_id' => $user2->id,
    'message' => $faker->sentence()
]);
$message1->save();

if(mt_rand(0,1) === 1) {
    // add message reply
    $message2 = new Message([
        'message_id' => $message1->id,
        'post_id' => $post->id,
        'to_user_id' => $user2->id,
        'from_user_id' => $user1->id,
        'message' => $faker->sentence()
    ]);

    $message2->save();
}
});

//使用模型工厂

<?php

use Illuminate\Database\Seeder;
use App\Models\Message;

class MessagesTableSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
        factory(Message::class, 200)->create();
    }
}

Answer 1

您收到错误是因为Model Factory definition需要返回一个包含您正在创建的Model实例的属性的数组。

使用您当前的代码，您最终将获得至少1个或最终2个新的消息（如果mt_rand(0,1)等于true）。但是，第一次执行后，factory()调用将始终失败。试试这个：

模型工厂：

$factory->define(App\Message::class, function(Faker\Generator $faker) {

    $userIds = App\User::all()->pluck('id')->toArray();
    $postIds = App\Post::all()->pluck('id')->toArray();
    $post = App\Post::find($faker->randomElement($postIds));
    $user1 = App\User::find($faker->randomElement($userIds));
    $user2 = App\User::find($faker->randomElement($userIds));

    return [
        'message_id' => null, // default NULL
        'post_id' => $post->id,
        'to_user_id' => $user1->id,
        'from_user_id' => $user2->id,
        'message' => $faker->sentence()
    ];
});

<强> MessagesTableSeeder ：

class MessagesTableSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
        factory(App\Message::class, 200)
            ->create()
            ->each(function ($m) {
                if(mt_rand(0,1) === 1) {
                    factory(App\Message::class)
                        ->create([
                            'message_id' => $m->id, // Overrides NULL attribute
                            'post_id' => $m->post_id, // Ensures same post
                            'to_user_id' => $m->from_user_id, // Switch from & to from relation
                            'from_user_id' => $m->to_user_id,
                        ]);
                }
            });
    }
}