Laravel scope query with nested models in 3-way pivot table - php

Question

I have a Product Model that needs to be connected with Processings, that describe how the Product can be manipulated, and Positions, that describe where the Product can be manipulated.
In other words, a Product can be processed into multiple positions.
The "Product Data" should be returned with nested processings into positions, so that, for every Position into the database, a Product can be associated with related Processings, in a scheme similar to the one below:
Products [
product_attributes,
Positions [
position_attributes,
Processings: [
processing_attributes
]
]
]
So, I have created a 3-way Pivot Table with the following code:
Schema::create('product_position_processing', function (Blueprint $table) {
// 3-way pivot
$table->integer('product_id')->unsigned()->index();
$table->foreign('product_id', 'ppp_aid_foreign')->references('id')->on('products')->onDelete('cascade');
$table->integer('position_id')->unsigned()->index();
$table->foreign('position_id', 'ppp_bid_foreign')->references('id')->on('positions')->onDelete('cascade');
$table->integer('processing_id')->unsigned()->index();
$table->foreign('processing_id', 'ppp_cid_foreign')->references('id')->on('processings')->onDelete('cascade');
$table->primary(['product_id', 'position_id', 'processing_id'], 'index-base-combined');
// these attributes define the minimum and maximum order amount based on the product + position + processing combination
$table->integer('minimum_order_amount')->nullable();
$table->integer('maximum_order_amount')->nullable();
$table->timestamps();
});
Then, I have defined the relations between the 3 different models in this way:
Processing Model
class Processing extends Model {
use SoftDeletes;
protected $dates = ['deleted_at'];
protected $guarded = ['id', 'created_at', 'updated_at'];
protected $casts = [
'is_publicly_hidden' => 'boolean'
];
protected $hidden = ['pivot'];
public function products() {
return $this -> belongsToMany ( Product::class, 'product_position_processing', 'processing_id', 'product_id' );
}
public function positions () {
return $this -> belongsToMany ( Position::class, 'product_position_processing', 'processing_id', 'position_id' );
}
...
...
}
Position Model
class Position extends Model {
use SoftDeletes;
protected $dates = ['deleted_at'];
protected $guarded = ['id', 'created_at', 'updated_at'];
protected $hidden = ['pivot'];
public function products() {
return $this->belongsToMany ( Product::class, 'product_position_processing', 'position_id', 'product_id' );
}
public function processings ( ) {
return $this -> belongsToMany ( Processing::class, 'product_position_processing', 'position_id', 'processing_id' );
}
...
...
}
Product Model
class Product extends Model implements SluggableInterface {
use SoftDeletes;
use SluggableTrait;
protected $dates = ['deleted_at'];
protected $guarded = ['id', 'created_at', 'updated_at'];
protected $sluggable = [
'build_from' => 'name',
'save_to' => 'slug',
'include_trashed' => true
];
...
...
public function processings() {
return $this->belongsToMany(Processing::class, 'product_position_processing', 'product_id', 'processing_id');
}
public function positions() {
return $this->belongsToMany(Position::class, 'product_position_processing', 'product_id', 'position_id');
}
...
...
public function scopeWithCompleteData ($query) {
return $query->with([
...
...
'positions' => function($query) {
return $query->with(['processings' => function ( $query ) {
return $query->select('id', 'name')->groupBy('processing_id');
}])->groupBy('position_id');
},
...
...
]);
}
}
Now, the Products are returned in json via the ProductsController that, with the following code, returns a JSON in this format.
Product Getter:
...
...
$products = Product::withCompleteData() -> get();
return $this -> ok ( $products );
Example "ALL Products" #get JSON:
{
"status": "OK",
"data": [
{
"id": 1,
"category_id": 1,
"subcategory_id": 0,
"brand_id": 1,
"sku": "BD615149D6",
...
...
"positions": [
{
"id": 1,
"name": "POS1",
"processings": [
{
"id": 1,
"name": "PROC1",
"pivot": {
"position_id": 1,
"processing_id": 1
}
},
{
"id": 2,
"name": "PROC2",
"pivot": {
"position_id": 1,
"processing_id": 2
}
},
{
"id": 3,
"name": "PROC3",
"pivot": {
"position_id": 1,
"processing_id": 3
}
}
]
},
{
"id": 2,
"name": "POS2",
"created_at": "2016-08-01 07:39:11",
"updated_at": null,
"deleted_at": null,
"processings": []
},
{
"id": 3,
"name": "POS3",
"created_at": "2016-08-01 07:39:11",
"updated_at": null,
"deleted_at": null,
"processings": []
}
]
},
{
"id": 2,
"category_id": 2,
"subcategory_id": 0,
"brand_id": 2,
"sku": "BD615149D6",
...
...
"positions": [
{
"id": 5,
"name": "POS5",
"created_at": "2016-08-01 07:39:11",
"updated_at": null,
"deleted_at": null,
"processings": []
}
]
}
]
}
The problem is, the data returned is not correct. The Query Builder seems to connect the various relationships in a strange way. Unfortunately I'm still not enough proactive in understanding what lies below the magic of the query builder, and don't know how to debug and where to make modifications to the code.
Can anyone help out with this 3-way pivot table with nested objects into the Laravel query builder?