DataLoader::loadMany() - Code Metrics - Inspection of "Merge branch 'master' of github.com:lordthorzonus/..." - lordthorzonus/php-dataloader - Measure and Improve Code Quality continuously with Scrutinizer

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by Juuso

created 2020-05-07 13:27 UTC

DataLoader::loadMany() A

↳ Parent: Project

Complexity

Conditions	1
Paths	1

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	6
CRAP Score	1

Importance

Changes

Metric	Value
dl	0
loc	11
ccs	6
cts	6
cp	1
rs	9.9
c	0
b	0
f	0
cc	1
nc	1
nop	1
crap	1

<?php

declare(strict_types=1);

namespace leinonen\DataLoader;

use React\Promise\Promise;
use function React\Promise\all;
use function React\Promise\reject;
use React\EventLoop\LoopInterface;
use function React\Promise\resolve;
use React\Promise\ExtendedPromiseInterface;

final class DataLoader implements DataLoaderInterface
{
    /**
     * @var callable
     */
    private $batchLoadFunction;

    private array $promiseQueue = [];


    private CacheMapInterface $promiseCache;

    private LoopInterface $eventLoop;

    private DataLoaderOptions $options;

    /**
     * Initiates a new DataLoader.
     *
     * @param callable $batchLoadFunction The function which will be called for the batch loading.
     * It must accept an array of keys and returns a Promise which resolves to an array of values.
     * @param LoopInterface $loop
     * @param CacheMapInterface $cacheMap
     * @param null|DataLoaderOptions $options
     */
    public function __construct(
        callable $batchLoadFunction,
        LoopInterface $loop,
        CacheMapInterface $cacheMap,
        DataLoaderOptions $options = null
    ) {
        $this->batchLoadFunction = $batchLoadFunction;
        $this->eventLoop = $loop;
        $this->promiseCache = $cacheMap;
        $this->options = $options ?? new DataLoaderOptions();
    }

    /**
     * {@inheritdoc}
     */
    public function load($key): ExtendedPromiseInterface
    {
        if ($key === null) {
            throw new \InvalidArgumentException(self::class . '::load must be called with a value, but got null');
        }

        if ($this->options->shouldCache() && $this->promiseCache->get($key)) {
            return $this->promiseCache->get($key);
        }

        $promise = new Promise(
            function (callable $resolve, callable $reject) use ($key) {
                $this->promiseQueue[] = [
                    'key' => $key,
                    'resolve' => $resolve,
                    'reject' => $reject,
                ];

                if (\count($this->promiseQueue) === 1) {
                    $this->scheduleDispatch();
                }
            }
        );

        if ($this->options->shouldCache()) {
            $this->promiseCache->set($key, $promise);
        }

        return $promise;
    }

    /**
     * {@inheritdoc}
     */
    public function loadMany(array $keys): ExtendedPromiseInterface
    {
        return all(
            \array_map(
                fn($key) => $this->load($key),
                $keys
            )
        );
    }

    /**
     * {@inheritdoc}
     */
    public function clear($key): void
    {
        $this->promiseCache->delete($key);
    }

    /**
     * {@inheritdoc}
     */
    public function clearAll(): void
    {
        $this->promiseCache->clear();
    }

    /**
     * {@inheritdoc}
     */
    public function prime($key, $value): void
    {
        if (! $this->promiseCache->get($key)) {
            // Cache a rejected promise if the value is an Exception, in order to match
            // the behavior of load($key).
            $promise = $value instanceof \Exception ? reject($value) : resolve($value);

            $this->promiseCache->set($key, $promise);
        }
    }

    /**
     * Schedules the dispatch to happen on the next tick of the EventLoop
     * If batching is disabled, schedule the dispatch immediately.
     *
     * @return void
     */
    private function scheduleDispatch(): void
    {
        if ($this->options->shouldBatch()) {
            $this->eventLoop->futureTick(
                fn() => $this->dispatchQueue()
            );

            return;
        }

        $this->dispatchQueue();
    }

    /**
     * Resets and dispatches the DataLoaders queue.
     *
     * @return void
     */
    private function dispatchQueue(): void
    {
        $queue = $this->promiseQueue;
        $this->promiseQueue = [];

        $maxBatchSize = $this->options->getMaxBatchSize();
        $shouldBeDispatchedInMultipleBatches = $maxBatchSize !== null
            && $maxBatchSize > 0
            && $maxBatchSize < count($queue);

        $shouldBeDispatchedInMultipleBatches
            ? $this->dispatchQueueInMultipleBatches($queue, $maxBatchSize)
            : $this->dispatchQueueBatch($queue);
    }

    /**
     * Dispatches a batch of a queue. The given batch can also be the whole queue.
     *
     * @param array $batch
     */
    private function dispatchQueueBatch($batch)
    {
        $keys = \array_column($batch, 'key');
        $batchLoadFunction = $this->batchLoadFunction;

        /** @var Promise $batchPromise */
        $batchPromise = $batchLoadFunction($keys);

        try {
            $this->validateBatchPromise($batchPromise);
        } catch (DataLoaderException $exception) {
            return $this->handleFailedDispatch($batch, $exception);
        }

        $batchPromise
            ->then(
                function ($values) use ($batch, $keys) {
                    $this->validateBatchPromiseOutput($values, $keys);
                    $this->handleSuccessfulDispatch($batch, $values);
                }
            )
            ->then(null, fn($error)  => $this->handleFailedDispatch($batch, $error));
    }

    /**
     * Dispatches the given queue in multiple batches.
     *
     * @param array $queue
     * @param int $maxBatchSize
     *
     * @return void
     */
    private function dispatchQueueInMultipleBatches(array $queue, $maxBatchSize): void
    {
        $numberOfBatchesToDispatch = \count($queue) / $maxBatchSize;

        for ($i = 0; $i < $numberOfBatchesToDispatch; $i++) {
            $this->dispatchQueueBatch(
                \array_slice($queue, $i * $maxBatchSize, $maxBatchSize)
            );
        }
    }

    /**
     * Handles the batch by resolving the promises and rejecting ones that return Exceptions.
     *
     * @param array $batch
     * @param array $values
     */
    private function handleSuccessfulDispatch(array $batch, array $values): void
    {
        foreach ($batch as $index => $queueItem) {
            $value = $values[$index];
            $value instanceof \Exception
                ? $queueItem['reject']($value)
                : $queueItem['resolve']($value);
        }
    }

    /**
     * Handles the failed batch dispatch.
     *
     * @param array $batch
     * @param \Exception $error
     */
    private function handleFailedDispatch(array $batch, \Exception $error)
    {
        foreach ($batch as $index => $queueItem) {
            // We don't want to cache individual loads if the entire batch dispatch fails.
            $this->clear($queueItem['key']);
            $queueItem['reject']($error);
        }
    }

    /**
     * Validates the batch promise's output.
     *
     * @param array $values Values from resolved promise.
     * @param array $keys Keys which the DataLoaders load was called with
     *
     * @throws DataLoaderException
     */
    private function validateBatchPromiseOutput($values, $keys): void
    {
        if (! \is_array($values)) {
            throw new DataLoaderException(
                self::class . ' must be constructed with a function which accepts ' .
                'an array of keys and returns a Promise which resolves to an array of values ' .
                \sprintf('not return a Promise: %s.', \gettype($values))
            );
        }

        if (\count($values) !== \count($keys)) {
            throw new DataLoaderException(
                self::class . ' must be constructed with a function which accepts ' .
                'an array of keys and returns a Promise which resolves to an array of values, but ' .
                'the function did not return a Promise of an array of the same length as the array of keys.' .
                \sprintf("\n Keys: %s\n Values: %s\n", \count($keys), \count($values))
            );
        }
    }

    /**
     * Validates the batch promise returned from the batch load function.
     *
     * @param $batchPromise
     *
     * @throws DataLoaderException
     */
    private function validateBatchPromise($batchPromise): void
    {
        if (! $batchPromise || ! \is_callable([$batchPromise, 'then'])) {
            throw new DataLoaderException(
                self::class . ' must be constructed with a function which accepts ' .
                'an array of keys and returns a Promise which resolves to an array of values ' .
                \sprintf('the function returned %s.', \gettype($batchPromise))
            );
        }
    }
}


1		<?php
2
3		declare(strict_types=1);
4
5		namespace leinonen\DataLoader;
6
7		use React\Promise\Promise;
8		use function React\Promise\all;
9		use function React\Promise\reject;
10		use React\EventLoop\LoopInterface;
11		use function React\Promise\resolve;
12		use React\Promise\ExtendedPromiseInterface;
13
14		final class DataLoader implements DataLoaderInterface
15		{
16		/**
17		* @var callable
18		*/
19		private $batchLoadFunction;
20
21		private array $promiseQueue = [];
		0 ignored issues – show Bug introduced 2020-05-07 13:37 UTC by Report Bug Copy Issue Report This code did not parse for me. Apparently, there is an error somewhere around this line: Syntax error, unexpected T_ARRAY, expecting T_FUNCTION or T_CONST Loading history...
22
23		private CacheMapInterface $promiseCache;
24
25		private LoopInterface $eventLoop;
26
27		private DataLoaderOptions $options;
28
29		/**
30		* Initiates a new DataLoader.
31		*
32		* @param callable $batchLoadFunction The function which will be called for the batch loading.
33		* It must accept an array of keys and returns a Promise which resolves to an array of values.
34		* @param LoopInterface $loop
35		* @param CacheMapInterface $cacheMap
36		* @param null\|DataLoaderOptions $options
37		*/
38		public function __construct(
39		callable $batchLoadFunction,
40		LoopInterface $loop,
41		CacheMapInterface $cacheMap,
42		DataLoaderOptions $options = null
43		) {
44		$this->batchLoadFunction = $batchLoadFunction;
45		$this->eventLoop = $loop;
46		$this->promiseCache = $cacheMap;
47		$this->options = $options ?? new DataLoaderOptions();
48		}
49
50	32	/**
51		* {@inheritdoc}
52		*/
53		public function load($key): ExtendedPromiseInterface
54		{
55		if ($key === null) {
56	32	throw new \InvalidArgumentException(self::class . '::load must be called with a value, but got null');
57	32	}
58	32
59	32	if ($this->options->shouldCache() && $this->promiseCache->get($key)) {
60	32	return $this->promiseCache->get($key);
61		}
62
63		$promise = new Promise(
64		function (callable $resolve, callable $reject) use ($key) {
65	32	$this->promiseQueue[] = [
66		'key' => $key,
67	32	'resolve' => $resolve,
68	2	'reject' => $reject,
69		];
70
71	30	if (\count($this->promiseQueue) === 1) {
72	9	$this->scheduleDispatch();
73		}
74		}
75	29	);
76
77	29	if ($this->options->shouldCache()) {
78	29	$this->promiseCache->set($key, $promise);
79	29	}
80	29
81		return $promise;
82		}
83	29
84	29	/**
85		* {@inheritdoc}
86	29	*/
87		public function loadMany(array $keys): ExtendedPromiseInterface
88		{
89	29	return all(
90	28	\array_map(
91		fn($key) => $this->load($key),
92		$keys
93	29	)
94		);
95		}
96
97		/**
98		* {@inheritdoc}
99	2	*/
100		public function clear($key): void
101	2	{
102	2	$this->promiseCache->delete($key);
103		}
104	2
105	2	/**
106	2	* {@inheritdoc}
107		*/
108		public function clearAll(): void
109		{
110		$this->promiseCache->clear();
111		}
112
113		/**
114	11	* {@inheritdoc}
115		*/
116	11	public function prime($key, $value): void
117	11	{
118		if (! $this->promiseCache->get($key)) {
119		// Cache a rejected promise if the value is an Exception, in order to match
120		// the behavior of load($key).
121		$promise = $value instanceof \Exception ? reject($value) : resolve($value);
122	1
123		$this->promiseCache->set($key, $promise);
124	1	}
125	1	}
126
127		/**
128		* Schedules the dispatch to happen on the next tick of the EventLoop
129		* If batching is disabled, schedule the dispatch immediately.
130	4	*
131		* @return void
132	4	*/
133		private function scheduleDispatch(): void
134		{
135	4	if ($this->options->shouldBatch()) {
136		$this->eventLoop->futureTick(
137	4	fn() => $this->dispatchQueue()
138		);
139	4
140		return;
141		}
142
143		$this->dispatchQueue();
144		}
145
146		/**
147	29	* Resets and dispatches the DataLoaders queue.
148		*
149	29	* @return void
150	28	*/
151		private function dispatchQueue(): void
152	27	{
153	28	$queue = $this->promiseQueue;
154		$this->promiseQueue = [];
155
156	28	$maxBatchSize = $this->options->getMaxBatchSize();
157		$shouldBeDispatchedInMultipleBatches = $maxBatchSize !== null
158		&& $maxBatchSize > 0
159	1	&& $maxBatchSize < count($queue);
160	1
161		$shouldBeDispatchedInMultipleBatches
162		? $this->dispatchQueueInMultipleBatches($queue, $maxBatchSize)
163		: $this->dispatchQueueBatch($queue);
164		}
165
166		/**
167	28	* Dispatches a batch of a queue. The given batch can also be the whole queue.
168		*
169	28	* @param array $batch
170	28	*/
171		private function dispatchQueueBatch($batch)
172	28	{
173		$keys = \array_column($batch, 'key');
174	28	$batchLoadFunction = $this->batchLoadFunction;
175	1
176		/** @var Promise $batchPromise */
177	27	$batchPromise = $batchLoadFunction($keys);
178
179	28	try {
180		$this->validateBatchPromise($batchPromise);
181		} catch (DataLoaderException $exception) {
182		return $this->handleFailedDispatch($batch, $exception);
183		}
184
185		$batchPromise
186	28	->then(
187		function ($values) use ($batch, $keys) {
188	28	$this->validateBatchPromiseOutput($values, $keys);
189	28	$this->handleSuccessfulDispatch($batch, $values);
190		}
191		)
192	28	->then(null, fn($error) => $this->handleFailedDispatch($batch, $error));
193		}
194
195	28	/**
196	4	* Dispatches the given queue in multiple batches.
197	4	*
198		* @param array $queue
199		* @param int $maxBatchSize
200	24	*
201		* @return void
202	23	*/
203	21	private function dispatchQueueInMultipleBatches(array $queue, $maxBatchSize): void
204	24	{
205		$numberOfBatchesToDispatch = \count($queue) / $maxBatchSize;
206	3
207	24	for ($i = 0; $i < $numberOfBatchesToDispatch; $i++) {
208	24	$this->dispatchQueueBatch(
209		\array_slice($queue, $i * $maxBatchSize, $maxBatchSize)
210		);
211		}
212		}
213
214		/**
215		* Handles the batch by resolving the promises and rejecting ones that return Exceptions.
216		*
217		* @param array $batch
218	1	* @param array $values
219		*/
220	1	private function handleSuccessfulDispatch(array $batch, array $values): void
221		{
222	1	foreach ($batch as $index => $queueItem) {
223	1	$value = $values[$index];
224	1	$value instanceof \Exception
225		? $queueItem['reject']($value)
226		: $queueItem['resolve']($value);
227	1	}
228		}
229
230		/**
231		* Handles the failed batch dispatch.
232		*
233		* @param array $batch
234		* @param \Exception $error
235	21	*/
236		private function handleFailedDispatch(array $batch, \Exception $error)
237	21	{
238	21	foreach ($batch as $index => $queueItem) {
239	21	// We don't want to cache individual loads if the entire batch dispatch fails.
240	4	$this->clear($queueItem['key']);
241		$queueItem['reject']($error);
242	19	}
243		}
244
245	21	/**
246		* Validates the batch promise's output.
247		*
248		* @param array $values Values from resolved promise.
249		* @param array $keys Keys which the DataLoaders load was called with
250		*
251		* @throws DataLoaderException
252		*/
253	7	private function validateBatchPromiseOutput($values, $keys): void
254		{
255	7	if (! \is_array($values)) {
256		throw new DataLoaderException(
257	7	self::class . ' must be constructed with a function which accepts ' .
258	7	'an array of keys and returns a Promise which resolves to an array of values ' .
259		\sprintf('not return a Promise: %s.', \gettype($values))
260	7	);
261		}
262
263		if (\count($values) !== \count($keys)) {
264		throw new DataLoaderException(
265		self::class . ' must be constructed with a function which accepts ' .
266		'an array of keys and returns a Promise which resolves to an array of values, but ' .
267		'the function did not return a Promise of an array of the same length as the array of keys.' .
268		\sprintf("\n Keys: %s\n Values: %s\n", \count($keys), \count($values))
269		);
270	23	}
271		}
272	23
273	1	/**
274		* Validates the batch promise returned from the batch load function.
275		*
276	1	* @param $batchPromise
277		*
278		* @throws DataLoaderException
279		*/
280	22	private function validateBatchPromise($batchPromise): void
281	1	{
282		if (! $batchPromise \|\| ! \is_callable([$batchPromise, 'then'])) {
283		throw new DataLoaderException(
284		self::class . ' must be constructed with a function which accepts ' .
285	1	'an array of keys and returns a Promise which resolves to an array of values ' .
286		\sprintf('the function returned %s.', \gettype($batchPromise))
287		);
288	21	}
289		}
290		}
291

lordthorzonus / php-dataloader

Push — master ( a0576a...ebf6f0 )

DataLoader::loadMany() A

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