4. Relay

Object Identification

Facebook Relay Documentation

Facebook GraphQL Spec

To implement a GraphQL Type that adheres to the Relay Object Identification spec, make sure your type extends Nuwave\Relay\Support\Definition\RelayType and implements the resolveById and relayFields methods.

Example:

<?php

namespace App\GraphQL\Types;

use GraphQL;
use GraphQL\Type\Definition\Type;
use GraphQL\Type\Definition\ResolveInfo;
use Nuwave\Relay\Support\Definition\RelayType;

class CustomerType extends RelayType
{
    /**
     * Attributes of Type.
     *
     * @var array
     */
    protected $attributes = [
        'name' => 'Customer',
        'description' => 'A Customer model.',
    ];

    /**
     * Get customer by id.
     *
     * When the root 'node' query is called, it will use this method
     * to resolve the type by providing the id.
     *
     * @param  string $id
     * @return Customer
     */
    public function resolveById($id)
    {
        return Customer::find($id);
    }

    /**
     * Available fields of Type.
     *
     * @return array
     */
    public function relayFields()
    {
        return [
            // Note: You may omit the id field as it will be overwritten to adhere to
            // the NodeInterface
            'id' => [
                'type' => Type::nonNull(Type::id()),
                'description' => 'ID of the customer.'
            ],
            // ...
        ];
    }
}

Connections

Facebook Relay Documentation

Facebook GraphQL Spec

To create a connection, simply use GraphQL::connection('typeName', Closure). We need to pass back an object that implements the Illuminate\Contract\Pagination\LengthAwarePaginator interface. In this example, we'll add it to our CustomerType we created in the Object Identification section.

(You can omit the resolve function if you are working with an Eloquent model. The package will use the same code as show below to resolve the connection.)

Example:

<?php
// ...
use Illuminate\Pagination\LengthAwarePaginator;

class CustomerType extends RelayType
{
    // ...

    /**
     * Available fields of Type.
     *
     * @return array
     */
    public function relayFields()
    {
        return [
            // ...
            'orders' => GraphQL::connection('order', function ($customer, array $args, ResolveInfo $info) {
                // Note: This is just an example. This type of resolve functionality may not make sense for your
                // application so just use what works best for you. However, you will need to pass back an object
                // that implements the LengthAwarePaginator as mentioned above in order for it to work with the
                // Relay connection spec.
                $orders = $customer->orders;

                if (isset($args['first'])) {
                    $total       = $orders->count();
                    $first       = $args['first'];
                    $after       = $this->decodeCursor($args);
                    $currentPage = $first && $after ? floor(($first + $after) / $first) : 1;

                    return new Paginator(
                        $orders->slice($after)->take($first),
                        $total,
                        $first,
                        $currentPage
                    );
                }

                return new Paginator(
                    $orders,
                    $orders->count(),
                    $orders->count()
                );
            }),
            // Alternatively, you can let the package resolve this connection for you
            // by passing the name of the relationship.
            'orders' => GraphQL::connection('order', 'orders')
        ];
    }
}