Your Name
140 lines
3.8 KiB
PHP
140 lines
3.8 KiB
PHP
<?php
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namespace Nuwave\Lighthouse\Execution\DataLoader;
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use GraphQL\Deferred;
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/**
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* @deprecated implement your own batch loader instead.
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* @see \Nuwave\Lighthouse\Execution\BatchLoader\BatchLoaderRegistry to resolve instances.
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*/
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abstract class BatchLoader
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{
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/**
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* Active BatchLoader instances.
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*
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* @var array<string, static>
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*/
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protected static $instances = [];
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/**
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* Map from keys to metainfo for resolving.
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*
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* @var array<mixed, array<mixed>>
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*/
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protected $keys = [];
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/**
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* Map from keys to resolved values.
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*
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* @var array<mixed, mixed>
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*/
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protected $results = [];
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/**
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* Check if data has been loaded.
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*
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* @var bool
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*/
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protected $hasLoaded = false;
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/**
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* Return an instance of a BatchLoader for a specific field.
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*
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* @param string $loaderClass The class name of the concrete BatchLoader to instantiate
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* @param array<int|string> $pathToField Path to the GraphQL field from the root, is used as a key for BatchLoader instances
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* @param array<mixed> $constructorArgs Those arguments are passed to the constructor of the new BatchLoader instance
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* @return static
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*
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* @throws \Exception
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*/
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public static function instance(string $loaderClass, array $pathToField, array $constructorArgs = []): self
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{
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// The path to the field serves as the unique key for the instance
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$instanceName = static::instanceKey($pathToField);
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if (isset(self::$instances[$instanceName])) {
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return self::$instances[$instanceName];
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}
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return self::$instances[$instanceName] = app()->makeWith($loaderClass, $constructorArgs);
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}
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/**
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* Generate a unique key for the instance, using the path in the query.
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*
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* @param array<int|string> $path
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*/
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public static function instanceKey(array $path): string
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{
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$significantPathSegments = array_filter(
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$path,
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function ($path): bool {
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// Ignore numeric path entries, as those signify a list of fields.
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// Combining the queries for those is the very purpose of the
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// batch loader, so they must not be included.
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return ! is_numeric($path);
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}
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);
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$pathIgnoringLists = implode('.', $significantPathSegments);
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return 'nuwave/lighthouse/batchloader/'.$pathIgnoringLists;
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}
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/**
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* Remove all stored BatchLoaders.
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*
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* This is called after Lighthouse has resolved a query, so multiple
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* queries can be handled in a single request/session.
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*/
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public static function forgetInstances(): void
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{
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self::$instances = [];
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}
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/**
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* Schedule a result to be loaded.
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*
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* @param array<mixed> $metaInfo
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*/
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public function load(string $key, array $metaInfo = []): Deferred
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{
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$this->keys[$key] = $metaInfo;
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return new Deferred(function () use ($key) {
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if (! $this->hasLoaded) {
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$this->results = $this->resolve();
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$this->hasLoaded = true;
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}
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return $this->results[$key];
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});
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}
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/**
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* Schedule multiple results to be loaded.
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*
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* @param array<mixed> $keys
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* @param array<mixed> $metaInfo
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* @return array<\GraphQL\Deferred>
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*/
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public function loadMany(array $keys, array $metaInfo = []): array
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{
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return array_map(
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function ($key) use ($metaInfo): Deferred {
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return $this->load($key, $metaInfo);
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},
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$keys
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);
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}
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/**
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* Resolve the keys.
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*
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* The result has to be a map from keys to resolved values.
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*
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* @return array<mixed, mixed>
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*/
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abstract public function resolve(): array;
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}
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