如何在Laravel Lighthouse GraphQL中按关联字段排序？

问题场景 #

Product模型与Category模型为一对一关联（Product属于Category），但执行getProducts查询时无法按Category的字段进行排序。

现有代码 #

GraphQL Schema

getProducts(orderBy: _ @orderBy): [Product!]! @all

type Product {
    id: ID
    code: String
    article: String

    category: Category
}
type Category {
    id: ID
    name: String
    products: [Product]
}

Laravel 模型代码

class Product extends Model
{
    ...
    public function category()
    {
        return $this->belongsTo(Category::class);
    }
}


class Category extends Model
{
    ...
    public function products()
    {
        return $this->hasMany(Product::class);
    }
}

解决方案 #

1. 创建ProductBuilder类

<?php

namespace App\GraphQL\Queries;

use Illuminate\Database\Eloquent\Builder;

class ProductBuilder
{
    public function getProducts(Builder $builder)
    {
        return $builder->join('categories', 'categories.id', '=', 'products.category_id');
    }
}

2. 更新GraphQL Schema中的查询定义

getProducts(orderBy: _ @orderBy): [Product!]!
    @all
    @builder(method: "App\GraphQL\Queries\ProductBuilder@getProducts")

3. 执行带关联字段排序的查询

{
    getProducts(orderBy: {column: "categories.name", order: ASC}){
        id
        code
        article
        category {
            name
       }
   }
}

内容的提问来源于stack exchange，提问作者Agustin