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

Question

I have Post and User model with one to one relation and it works well:

//User.php

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


// Post.php

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

now I create API resources:

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

I need to return all post with an API call then I set my route:

//web.php: /resource/posts

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

This is my Posts resource class:

<?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,
    ];
  
}
}

This is the error:

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

if I remove:

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

it works but I need to include relations in my API JSON, I have read and followed the doc at https://laravel.com/docs/5.5/collections.

This is my User resource class:

<?php

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
   ];
}
}

Any ideas where I am wrong?

Maraboc · Accepted Answer · 2025-06-04 09:51:06Z

155

The problem is that you use UserResource::collection($this->user) and you have just one element not a collection so you can replace it with new UserResource($this->user) or you can the static metod way UserResource::make($this->user) like this :

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

edited Jun 4 at 9:51

answered Dec 8, 2017 at 9:07

Maraboc

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3 Comments

Payam Khaninejad Over a year ago

In my case, I was using a collection in collection resource.

melih sahin Over a year ago

thank you so much . I chose to use it instead of using it in the array: paste.laravel.io/198efba2-9954-4c9c-856e-e053e0d1f584

basagabi Over a year ago

@runtimeTerror also mentioned the use of the static method make like so: UserResource::make($this->user). I would like to know what's difference between the two aside from the later is using a static method?

runtimeTerror · Accepted Answer · 2022-09-22 17:07:14Z

14

this problem is that you use UserResource::collection($this->user) it mean you have many users but and you have just one element for the a single resource and not a collection so you can replace it with new UserResource($this->user)

edited Sep 22, 2022 at 17:07

runtimeTerror

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answered Sep 21, 2019 at 8:19

Amirex

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Comments

runtimeTerror · Accepted Answer · 2021-09-20 17:39:42Z

13

In Laravel 8.5.*, you can use the static method make on the collection to get the same result. It would be like UserResource::make($this->user)

answered Sep 20, 2021 at 17:39

runtimeTerror

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Comments

Elio Muculo · Accepted Answer · 2022-07-19 16:41:43Z

6

when you have just one element and not a collection use new Resouce

return [
        'id' => $this->id,
        'name' => $this->name,
        'description' => $this->description,
        'user' => new UserResource($this->whenLoaded('user')),
];

and give a try to use the eager loading for better perfomance not just this. using the method whenLoaded and put the relations name in ( ).

Resource::collection is used when the model has hasMany relation. If your model has hasOne relation use Resource::make(Book::all())

edited Jul 19, 2022 at 16:41

answered Jul 19, 2022 at 16:33

Elio Muculo

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Comments

Md Zahid · Accepted Answer · 2023-03-22 09:40:55Z

The issue is that you use UserResource::collection($this->user) and you have just one element come from database, not list of collection. It would be solved if you used new UserResource($this->user) like this:

<?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' => $this->body,
        'users' => new UserResource($this->user),
        'published' => $this->published,
        'created_at' => $this->created_at,
        'updated_at' => $this->updated_at,
    ];

}
}

fatemeh sadeghi · Accepted Answer · 2024-04-24 18:47:47Z

1

use make instead of collection; because your relation is belongTo (one to one) and it is one record ** is not a collection** .when relation is hasMany or morphTomany use collection. use

UserResource::make($this->user)

instead

UserResource::collection($this->user)

edited Apr 24, 2024 at 18:47

answered Apr 24, 2024 at 18:31

fatemeh sadeghi

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