Fluent query plugin for SilverStripe GraphQL

_config.yml

SilverStripe\Core\Injector\Injector:
  SilverStripe\GraphQL\Schema\Registry\PluginRegistry:
    constructor:
      - Mutoco\GraphQL\FluentQueryPlugin

FluentQueryPlugin.php

<?php


namespace Mutoco\GraphQL;

use SilverStripe\GraphQL\Schema\Field\ModelQuery;
use SilverStripe\GraphQL\Schema\Interfaces\ModelQueryPlugin;
use SilverStripe\GraphQL\Schema\Interfaces\SchemaUpdater;
use SilverStripe\GraphQL\Schema\Schema;
use SilverStripe\GraphQL\Schema\Type\Enum;
use TractorCow\Fluent\Model\Locale;
use TractorCow\Fluent\State\FluentState;

class FluentQueryPlugin implements ModelQueryPlugin, SchemaUpdater
{
	public function getIdentifier(): string
	{
		return 'locale';
	}

	public static function updateSchema(Schema $schema, array $config = []): void
	{
		$locales = Locale::getLocales()->map('ID', 'Locale')->values();
		$locales = array_combine($locales, $locales);
		if (empty($locales)) {
			$locales = ['de_CH' => 'de_CH'];
		}
		$enum = Enum::create('Locale', $locales, 'The locales available');

		$schema->addEnum($enum);
	}

	public function apply(ModelQuery $query, Schema $schema, array $config = []): void
	{
		$queryType = $schema->getQueryType();
		// Ensure that we only apply the Locale variable to root queries.
		// Nested queries with their own locales is super edge-casey and weird.
		if (!$queryType->getFieldByName($query->getName())) {
			return;
		}

		$query->addArg('locale', 'Locale');
		$query->addResolverMiddleware([static::class, 'setLocale']);
	}

	public static function setLocale($obj, $args, $context)
	{
		FluentState::singleton()->setLocale($args['locale'] ?? 'de_CH');

		return $obj;
	}
}