2021-07-26 19:46:18 +02:00

124 lines
4.1 KiB
PHP

<?php
namespace Nuwave\Lighthouse\Defer;
use Closure;
use GraphQL\Error\Error;
use GraphQL\Language\AST\NonNullTypeNode;
use GraphQL\Language\AST\TypeNode;
use GraphQL\Type\Definition\Directive;
use GraphQL\Type\Definition\ResolveInfo;
use Nuwave\Lighthouse\ClientDirectives\ClientDirective;
use Nuwave\Lighthouse\Schema\Directives\BaseDirective;
use Nuwave\Lighthouse\Schema\RootType;
use Nuwave\Lighthouse\Schema\Values\FieldValue;
use Nuwave\Lighthouse\Support\Contracts\FieldMiddleware;
use Nuwave\Lighthouse\Support\Contracts\GraphQLContext;
class DeferrableDirective extends BaseDirective implements FieldMiddleware
{
public const THE_DEFER_DIRECTIVE_CANNOT_BE_USED_ON_A_ROOT_MUTATION_FIELD = 'The @defer directive cannot be used on a root mutation field.';
public const THE_DEFER_DIRECTIVE_CANNOT_BE_USED_ON_A_NON_NULLABLE_FIELD = 'The @defer directive cannot be used on a Non-Nullable field.';
public const DEFER_DIRECTIVE_NAME = 'defer';
public static function definition(): string
{
return /** @lang GraphQL */ <<<'GRAPHQL'
"""
Do not use this directive directly, it is automatically added to the schema
when using the defer extension.
"""
directive @deferrable on FIELD_DEFINITION
GRAPHQL;
}
/**
* @var \Nuwave\Lighthouse\Defer\Defer
*/
protected $defer;
public function __construct(Defer $defer)
{
$this->defer = $defer;
}
public function handleField(FieldValue $fieldValue, Closure $next): FieldValue
{
$previousResolver = $fieldValue->getResolver();
$fieldType = $fieldValue->getField()->type;
$fieldValue->setResolver(
function ($root, array $args, GraphQLContext $context, ResolveInfo $resolveInfo) use ($previousResolver, $fieldType) {
$wrappedResolver = function () use ($previousResolver, $root, $args, $context, $resolveInfo) {
return $previousResolver($root, $args, $context, $resolveInfo);
};
$path = implode('.', $resolveInfo->path);
if ($this->shouldDefer($fieldType, $resolveInfo)) {
return $this->defer->defer($wrappedResolver, $path);
}
return $this->defer->findOrResolve($wrappedResolver, $path);
}
);
return $next($fieldValue);
}
/**
* Determine if field should be deferred.
*
* @throws \GraphQL\Error\Error
*/
protected function shouldDefer(TypeNode $fieldType, ResolveInfo $resolveInfo): bool
{
$defers = (new ClientDirective(self::DEFER_DIRECTIVE_NAME))->forField($resolveInfo);
if ($this->anyFieldHasDefer($defers)) {
if ($resolveInfo->parentType->name === RootType::MUTATION) {
throw new Error(self::THE_DEFER_DIRECTIVE_CANNOT_BE_USED_ON_A_ROOT_MUTATION_FIELD);
}
if ($fieldType instanceof NonNullTypeNode) {
throw new Error(self::THE_DEFER_DIRECTIVE_CANNOT_BE_USED_ON_A_NON_NULLABLE_FIELD);
}
}
// Following the semantics of Apollo:
// All declarations of a field have to contain @defer for the field to be deferred
foreach ($defers as $defer) {
if ($defer === null || $defer === [Directive::IF_ARGUMENT_NAME => false]) {
return false;
}
}
$skips = (new ClientDirective(Directive::SKIP_NAME))->forField($resolveInfo);
foreach ($skips as $skip) {
if ($skip === [Directive::IF_ARGUMENT_NAME => true]) {
return false;
}
}
$includes = (new ClientDirective(Directive::INCLUDE_NAME))->forField($resolveInfo);
return ! in_array(
[Directive::IF_ARGUMENT_NAME => false],
$includes,
true
);
}
/**
* @param array<array<string, mixed>|null> $defers
*/
protected function anyFieldHasDefer(array $defers): bool
{
foreach ($defers as $defer) {
if ($defer !== null) {
return true;
}
}
return false;
}
}