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<?php |
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/** |
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* This file is part of the Rate Limit package. |
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* |
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* Copyright (c) Nikola Posa |
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* |
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* For full copyright and license information, please refer to the LICENSE file, |
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* located at the package root folder. |
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*/ |
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declare(strict_types=1); |
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namespace RateLimit; |
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use Psr\Http\Message\RequestInterface; |
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use Psr\Http\Message\ResponseInterface; |
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use RateLimit\Storage\StorageInterface; |
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use RateLimit\Identity\IdentityGeneratorInterface; |
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use RateLimit\Identity\IpAddressIdentityGenerator; |
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use RateLimit\Exception\StorageRecordNotExistException; |
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/** |
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* @author Nikola Posa <[email protected]> |
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*/ |
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final class RequestsPerWindowRateLimiter implements RateLimiterInterface |
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{ |
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const LIMIT_EXCEEDED_HTTP_STATUS_CODE = 429; //HTTP 429 "Too Many Requests" (RFC 6585) |
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const HEADER_LIMIT = 'X-RateLimit-Limit'; |
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const HEADER_REMAINING = 'X-RateLimit-Remaining'; |
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const HEADER_RESET = 'X-RateLimit-Reset'; |
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/** |
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* @var StorageInterface |
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*/ |
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private $storage; |
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/** |
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* @var array |
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*/ |
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private $options; |
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/** |
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* @var IdentityGeneratorInterface |
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*/ |
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private $identityGenerator; |
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/** |
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* @var array |
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*/ |
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private $rateLimit; |
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/** |
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* @var array |
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*/ |
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private static $defaultOptions = [ |
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'limit' => 100, |
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'window' => 900, //15 minutes |
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'limitExceededHandler' => null, |
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]; |
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private function __construct(StorageInterface $storage, array $options, IdentityGeneratorInterface $identityGenerator) |
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{ |
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$this->storage = $storage; |
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$this->options = $options; |
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$this->identityGenerator = $identityGenerator; |
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} |
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public static function create(StorageInterface $storage, array $options = [], IdentityGeneratorInterface $identityGenerator = null) |
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{ |
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return new self( |
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$storage, |
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array_merge(self::$defaultOptions, $options), |
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$identityGenerator ?? new IpAddressIdentityGenerator() |
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); |
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} |
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/** |
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* {@inheritdoc} |
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*/ |
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public function __invoke(RequestInterface $request, ResponseInterface $response, callable $out = null) |
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{ |
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$key = $this->identityGenerator->getIdentity($request); |
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$this->initRateLimit($key); |
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if ($this->isLimitExceeded()) { |
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return $this->onLimitExceeded($request, $response); |
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} |
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if ($this->shouldResetRateLimit()) { |
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$this->resetRateLimit(); |
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} else { |
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$this->updateRateLimit(); |
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} |
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$this->storage->set($key, $this->rateLimit); |
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return $this->onBelowLimit($request, $response, $out); |
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} |
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private function initRateLimit(string $key) |
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{ |
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try { |
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$rateLimit = $this->storage->get($key); |
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} catch (StorageRecordNotExistException $ex) { |
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$rateLimit = [ |
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'remaining' => $this->options['limit'], |
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'reset' => time() + $this->options['window'], |
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]; |
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} |
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$this->rateLimit = $rateLimit; |
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} |
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private function isLimitExceeded() : bool |
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{ |
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return $this->rateLimit['remaining'] <= 0; |
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} |
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private function updateRateLimit() |
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{ |
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$this->rateLimit['remaining']--; |
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} |
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private function shouldResetRateLimit() : bool |
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{ |
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return time() >= $this->rateLimit['reset']; |
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} |
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private function resetRateLimit() |
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{ |
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$this->rateLimit = [ |
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'remaining' => $this->options['limit'], |
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'reset' => time() + $this->options['window'], |
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]; |
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} |
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private function onLimitExceeded(RequestInterface $request, ResponseInterface $response) : ResponseInterface |
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{ |
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$response = $this |
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->setRateLimitHeaders($response) |
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->withStatus(self::LIMIT_EXCEEDED_HTTP_STATUS_CODE) |
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; |
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$limitExceededHandler = $this->options['limitExceededHandler']; |
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if (null !== $limitExceededHandler && is_callable($limitExceededHandler)) { |
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$response = $limitExceededHandler($request, $response); |
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} |
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return $response; |
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} |
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private function onBelowLimit(RequestInterface $request, ResponseInterface $response, callable $out = null) : ResponseInterface |
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{ |
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$response = $this->setRateLimitHeaders($response); |
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return $out ? $out($request, $response) : $response; |
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} |
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private function setRateLimitHeaders(ResponseInterface $response) : ResponseInterface |
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{ |
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return $response |
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->withHeader(self::HEADER_LIMIT, (string) $this->options['limit']) |
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->withHeader(self::HEADER_REMAINING, (string) $this->rateLimit['remaining']) |
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->withHeader(self::HEADER_RESET, (string) $this->rateLimit['reset']) |
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; |
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} |
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} |
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Our type inference engine has found an assignment to a property that is incompatible with the declared type of that property.
Either this assignment is in error or the assigned type should be added to the documentation/type hint for that property..