laravel APi资源调用未定义的方法Illuminate \ Database \ Query \ Builder :: mapInto（）

Question

我有一对一关系的Post和User模型，它运作良好：

//User.php

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


// Post.php

public function user() {
    return $this->belongsTo(User::class);
}

现在我创建API资源：

php artisan make:resource Post
php artisan make:resource User

我需要通过api调用返回所有帖子然后我设置我的路线：

//web.php: /resource/posts

Route::get('/resource/posts', function () {
    return PostResource::collection(Post::all());
});

这是我的帖子资源类：

<?php

namespace App\Http\Resources;
use Illuminate\Http\Resources\Json\Resource;
use App\Http\Resources\User as UserResource;

class Posts extends Resource
{
/**
 * Transform the resource into an array.
 *
 * @param  \Illuminate\Http\Request  $request
 * @return array
 */
public function toArray($request)
{
      return [
        'id' => $this->id,
        'title' => $this->title,
        'slug' => $this->slug,
        'bodys' => $this->body,
        'users' => UserResource::collection($this->user),
        'published' => $this->published,
        'created_at' => $this->created_at,
        'updated_at' => $this->updated_at,
    ];

}
}

这是错误：

Call to undefined method Illuminate\Database\Query\Builder::mapInto()

如果我删除：

'users' => UserResource::collection($this->user),

它的工作，但我需要在我的api json中包含关系，我已阅读并关注https://laravel.com/docs/5.5/collections的文档。

这是我的用户资源类：

```

namespace App\Http\Resources;

use Illuminate\Http\Resources\Json\Resource;

class User extends Resource
{
/**
 * Transform the resource into an array.
 *
 * @param  \Illuminate\Http\Request  $request
 * @return array
 */
public function toArray($request)
{
   return [
       'user_id' => $this->user_id,
       'name' => $this->name,
       'lastname' => $this->lastname,
       'email' => $this->email
   ];
}
}

任何想法我错在哪里？

Answer 1

问题是你使用UserResource::collection($this->user)并且你只有一个元素而不是集合所以你可以用new UserResource($this->user)替换它：

return [
    'id' => $this->id,
    'title' => $this->title,
    'slug' => $this->slug,
    'bodys' => $this->body,
    'users' => new UserResource($this->user),
    'published' => $this->published,
    'created_at' => $this->created_at,
    'updated_at' => $this->updated_at,
];