Laravel中返回关联模型时如何隐藏post_id字段？

我有如下代码（App\Controllers\ImageController.php）：

.....
    $image = new Image;   
    $image->id = "pre_" . (string) Str::ulid()->toBase58();     
    $image->filename = $filename;
    $image->post_id= $post_id;
    $image->save();
    
    return $image->load("post:id,status,subject,body");

这段代码运行正常，返回数据如下：

{
  "id": "pre_1BzVrTK8dviqA9FGxSoSnU",
  "type": "document",
  "filename": "v1BzVc3jJPp64e7bQo1drmL.jpeg",
  "post_id": "post_1BzVc3jJPp64e7bQo1drmL",
  "post": {
    "id": "post_1BzVc3jJPp64e7bQo1drmL",
    "status": "active"
    ....
  }
 ....
}

Image模型代码（App\Models\Image.php）：

class Image extends Model
{
    use HasFactory;

    public $incrementing = false; 

    public function post()
    {
        return $this->belongsTo(Post::class);
    }
}

现在需要返回结果中不包含post_id字段，期望结构：

{
      "id": "pre_1BzVrTK8dviqA9FGxSoSnU",
      "type": "document",
      "filename": "v1BzVc3jJPp64e7bQo1drmL.jpeg",
      "post": {
        "id": "post_1BzVc3jJPp64e7bQo1drmL",
        "status": "active"
        ....
      }
     ....
    }

我尝试了以下代码：

return $image->select(["id", "type", "filename"])->load("post:id,status,subject,body");

但报错：

"message": "Call to undefined method Illuminate\Database\Eloquent\Builder::load()"

报错原因 #

select()方法返回的是查询构造器（Builder实例），而load()是Eloquent模型实例的专属方法，两者无法链式调用。且你已经创建并保存了模型实例，不需要用select来筛选字段。

方法1：全局隐藏字段 #

在Image模型中添加$hidden属性，全局隐藏post_id：

class Image extends Model
{
    use HasFactory;

    public $incrementing = false; 
    // 全局隐藏post_id字段
    protected $hidden = ['post_id'];

    public function post()
    {
        return $this->belongsTo(Post::class);
    }
}

控制器代码无需修改，直接返回加载关联后的模型即可：

return $image->load("post:id,status,subject,body");

方法2：临时隐藏字段 #

如果仅需要在当前请求中隐藏post_id，使用makeHidden()方法：

return $image->load("post:id,status,subject,body")->makeHidden(['post_id']);

方法3：API资源（复杂场景推荐） #

若需要更灵活的返回结构控制，创建ImageResource：

// app/Http/Resources/ImageResource.php
namespace App\Http\Resources;

use Illuminate\Http\Resources\Json\JsonResource;

class ImageResource extends JsonResource
{
    public function toArray($request)
    {
        return [
            'id' => $this->id,
            'type' => $this->type,
            'filename' => $this->filename,
            'post' => [
                'id' => $this->post->id,
                'status' => $this->post->status,
                'subject' => $this->post->subject,
                'body' => $this->post->body
                // 按需添加其他字段
            ]
            // 按需添加Image模型的其他字段
        ];
    }
}

控制器中返回资源：

return new ImageResource($image->load("post:id,status,subject,body"));

内容的提问来源于stack exchange，提问作者DeveloperX