Question

我的问题是关于自定义指令 https://lighthouse-php.com/4.11/the-basics/directives.html#definition

我的模式是：

type Query {
  sayFriendly: String @append(text: ", please.")
}

在lighthouse.php的配置中，我已经拥有

'namespaces' => [
        'models' => ['App', 'App\\Models'],
        'queries' => 'App\\GraphQL\\Queries',
        'mutations' => 'App\\GraphQL\\Mutations',
        'subscriptions' => 'App\\GraphQL\\Subscriptions',
        'interfaces' => 'App\\GraphQL\\Interfaces',
        'unions' => 'App\\GraphQL\\Unions',
        'scalars' => 'App\\GraphQL\\Scalars',
        'directives' => ['App\\GraphQL\\Directives'],
    ],

启用了指令。

我在\ App \ GraphQL \ Directives \ appendDirective中将指令定义为

<?php

namespace App\GraphQL\Directives;

use Closure;
use GraphQL\Type\Definition\ResolveInfo;
use Nuwave\Lighthouse\Schema\Values\FieldValue;
use Nuwave\Lighthouse\Support\Contracts\Directive;
use Nuwave\Lighthouse\Support\Contracts\FieldMiddleware;
use Nuwave\Lighthouse\Support\Contracts\GraphQLContext;

class appendDirective implements Directive, FieldMiddleware
{
    /**
     * Name of the directive as used in the schema.
     *
     * @return string
     */
    public function name(): string
    {
        return 'append';
    }

    /**
     * Wrap around the final field resolver.
     *
     * @param \Nuwave\Lighthouse\Schema\Values\FieldValue $fieldValue
     * @param \Closure $next
     * @return \Nuwave\Lighthouse\Schema\Values\FieldValue
     */
    public function handleField(FieldValue $fieldValue, Closure $next): FieldValue
    {

        // Retrieve the existing resolver function
        /** @var Closure $previousResolver */
        $previousResolver = $fieldValue->getResolver();

        // Wrap around the resolver
        $wrappedResolver = function ($root, array $args, GraphQLContext $context, ResolveInfo $info) use ($previousResolver): string {
            // Call the resolver, passing along the resolver arguments
            /** @var string $result */
            $result = $previousResolver($root, $args, $context, $info);
            return ($result);
        };

        // Place the wrapped resolver back upon the FieldValue
        // It is not resolved right now - we just prepare it
        $fieldValue->setResolver($wrappedResolver);

        // Keep the middleware chain going
        return $next($fieldValue);
    }

}

如何从指令中获取键“ text”的值并将其追加到$ result [@append（text：“，please。”）]。 $ args是一个空数组（这应该是因为我确实进行了参数化查询[sayFriendly]）

Answer 1

如果您从Nuwave\Lighthouse\Schema\Directives\BaseDirective扩展指令，则可以访问$this->directiveArgValue('text');来检索自定义指令的text参数。

$args为空，因为这是客户端在查询中提供的参数，在sayFriendly查询示例中，没有可能的参数，因此始终为空。

提示：您可以通过查看Lighthouse内部的already implemented directives来了解这一点，文档中的自定义指令有些精简，但是您可以通过查看灯塔。

如何在灯塔GraphQL Laravel中获取自定义指令参数

1 个答案: