Laravel 8工厂如何在无字段时传递参数至configure方法

场景背景 #

在Laravel 8项目（依赖fakerphp/faker: ^1.9）中，需要为News模型生成不同类型的测试媒体数据，但不需要在News表中存储news_media_type字段。最初代码尝试在definition方法返回数组中包含该字段，触发数据库报错；改用类的protected变量传递时，configure先执行导致变量为空，afterCreating中变量值又丢失。

最初代码与错误 #

最初的Factory代码试图将news_media_type放入返回数组，但News表无此字段，引发SQL错误：

<?php

class NewsFactory extends Factory
{
    protected $model = News::class;

    public function definition(): array
    {
        /// ...
        $newsMediaType = $this->faker->randomElement([
            '', /* no media */
            'Y', /* youtube url */
            'I', /* uploaded image */
            'V', /* uploaded video */
        ]);

        $youtubeUrl = '';

        if($newsMediaType === 'Y') {
            $this->faker->addProvider(new \Faker\Provider\Youtube($this->faker));
            $youtubeUrl = $this->faker->youtubeUri();
        }

        return [
            // ...
            'youtube_url' => $youtubeUrl,
            'news_media_type' => $newsMediaType, // 模型无此字段，导致插入失败
        ];
    }

    public function configure(): self
    {
        return $this->afterCreating(function (News $newNews) {
            if ($newNews->news_media_type === 'I') { 
                $newNews->addMediaFromUrl('https://loremflickr.com/480/360')
                    ->storingConversionsOnDisk('local')
                    ->toMediaCollection('news_images');
            }
        });
    }
}

错误信息：

SQLSTATE[42703]: Undefined column: 7 ERROR:  column "news_media_type" of relation "news" does not exist
LINE 1: ...t into "news" ("title", "content", "youtube_url", "news_medi...
   ^ (SQL: insert into "news" ("title", "content", "youtube_url", "news_media_type", "published_at", "created_at", 
   "updated_at") values (Test news Quo dolores laudantium illum., , , I, 2023-06-01 16:28:33, 2023-06-09 12:29:35, 
   2023-06-09 12:29:35) returning "id

尝试protected变量的问题 #

改用类成员变量$newsMediaType后，日志显示configure先执行（变量为空），definition赋值后，afterCreating闭包中变量值丢失：

<?php

namespace Database\Factories;

use App\Modules\News\Models\News;
use Illuminate\Database\Eloquent\Factories\Factory;

class NewsFactory extends Factory
{
    protected $model = News::class;
    protected $newsMediaType = null;
    
    public function definition(): array
    {
        $this->newsMediaType = $this->faker->randomElement(['', 'Y', 'I', 'V']);
        $this->newsMediaType = 'I'; // 测试固定值
        \Log::info(' -10 $this->newsMediaType::');
        \Log::info($this->newsMediaType);
        
        $youtubeUrl = '';
        if($this->newsMediaType === 'Y') {
            $this->faker->addProvider(new \Faker\Provider\Youtube($this->faker));
            $youtubeUrl = $this->faker->youtubeUri();
        }

        return [
            'youtube_url' => $youtubeUrl,
            ...
        ];
    }

    public function configure(): self
    {
        \Log::info( ' -12 $this->newsMediaType::');
        \Log::info($this->newsMediaType);
        return $this->afterCreating(function (News $newNews) {
            \Log::info( ' -14 $this->newsMediaType::');
            \Log::info($this->newsMediaType);
            if ($this->newsMediaType === 'I') {
                $newNews->addMediaFromUrl('https://loremflickr.com/480/360')
                    ->storingConversionsOnDisk('local')
                    ->toMediaCollection('news_images');
            }
        });
    }
}

日志输出：

[2023-06-10 06:10:50] local.INFO:  -12 $this->newsMediaType::
[2023-06-10 06:10:50] local.INFO:
[2023-06-10 06:10:50] local.INFO:  -10 $this->newsMediaType::
[2023-06-10 06:10:50] local.INFO: I
[2023-06-10 06:10:50] local.INFO:  -14 $this->newsMediaType::
[2023-06-10 06:10:50] local.INFO:

问题原因 #

1. 最初错误：definition返回的数组包含模型/数据表不存在的字段，Laravel会将所有返回字段插入数据库，导致SQL字段不存在错误。
2. 变量丢失原因：configure在Factory实例初始化时就执行，definition是创建模型时才执行；afterCreating闭包绑定的是初始化时的变量引用，后续definition对变量的修改无法同步到闭包中。

解决方案 #

方案1：使用Factory状态方法（推荐） #

为每种媒体类型定义独立状态，按需调用生成：

<?php

namespace Database\Factories;

use App\Modules\News\Models\News;
use Illuminate\Database\Eloquent\Factories\Factory;

class NewsFactory extends Factory
{
    protected $model = News::class;

    public function definition(): array
    {
        return [
            // 其他字段定义
            'youtube_url' => '',
        ];
    }

    // 无媒体
    public function noMedia(): self
    {
        return $this->state(fn (array $attributes) => []);
    }

    // YouTube视频
    public function youtube(): self
    {
        $this->faker->addProvider(new \Faker\Provider\Youtube($this->faker));
        return $this->state(fn (array $attributes) => [
            'youtube_url' => $this->faker->youtubeUri(),
        ]);
    }

    // 上传图片
    public function image(): self
    {
        return $this->afterCreating(function (News $news) {
            $news->addMediaFromUrl('https://loremflickr.com/480/360')
                ->storingConversionsOnDisk('local')
                ->toMediaCollection('news_images');
        });
    }

    // 上传视频
    public function video(): self
    {
        return $this->afterCreating(function (News $news) {
            $news->addMediaFromUrl('https://example.com/test-video.mp4')
                ->storingConversionsOnDisk('local')
                ->toMediaCollection('news_videos');
        });
    }
}

使用方式：

// 随机生成不同类型
$types = ['noMedia', 'youtube', 'image', 'video'];
News::factory()->{$this->faker->randomElement($types)}()->create();

// 生成指定类型
News::factory()->image()->create();

方案2：在definition中直接绑定闭包捕获变量 #

在definition中生成媒体类型后，直接创建afterCreating闭包并通过use捕获当前值：

<?php

namespace Database\Factories;

use App\Modules\News\Models\News;
use Illuminate\Database\Eloquent\Factories\Factory;

class NewsFactory extends Factory
{
    protected $model = News::class;

    public function definition(): array
    {
        $newsMediaType = $this->faker->randomElement(['', 'Y', 'I', 'V']);
        $youtubeUrl = '';

        if ($newsMediaType === 'Y') {
            $this->faker->addProvider(new \Faker\Provider\Youtube($this->faker));
            $youtubeUrl = $this->faker->youtubeUri();
        }

        // 闭包通过use捕获当前的$newsMediaType值
        $this->afterCreating(function (News $news) use ($newsMediaType) {
            if ($newsMediaType === 'I') {
                $news->addMediaFromUrl('https://loremflickr.com/480/360')
                    ->storingConversionsOnDisk('local')
                    ->toMediaCollection('news_images');
            } elseif ($newsMediaType === 'V') {
                $news->addMediaFromUrl('https://example.com/test-video.mp4')
                    ->storingConversionsOnDisk('local')
                    ->toMediaCollection('news_videos');
            }
        });

        return [
            // 其他字段
            'youtube_url' => $youtubeUrl,
        ];
    }
}

内容的提问来源于stack exchange，提问作者mstdmstd