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<?php |
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namespace GuzzleHttp; |
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|
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use GuzzleHttp\Promise\PromiseInterface; |
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use GuzzleHttp\Promise\RejectedPromise; |
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use GuzzleHttp\Psr7; |
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use Psr\Http\Message\RequestInterface; |
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use Psr\Http\Message\ResponseInterface; |
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|
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/** |
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* Middleware that retries requests based on the boolean result of |
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* invoking the provided "decider" function. |
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*/ |
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class RetryMiddleware |
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{ |
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/** @var callable */ |
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private $nextHandler; |
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|
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/** @var callable */ |
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private $decider; |
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|
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/** @var callable */ |
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private $delay; |
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|
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/** |
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* @param callable $decider Function that accepts the number of retries, |
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* a request, [response], and [exception] and |
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* returns true if the request is to be |
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* retried. |
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* @param callable $nextHandler Next handler to invoke. |
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* @param callable $delay Function that accepts the number of retries |
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* and [response] and returns the number of |
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* milliseconds to delay. |
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*/ |
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public function __construct( |
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callable $decider, |
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callable $nextHandler, |
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callable $delay = null |
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) { |
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$this->decider = $decider; |
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$this->nextHandler = $nextHandler; |
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$this->delay = $delay ?: __CLASS__ . '::exponentialDelay'; |
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} |
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|
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/** |
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* Default exponential backoff delay function. |
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* |
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* @param int $retries |
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* |
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* @return int |
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*/ |
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public static function exponentialDelay($retries) |
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{ |
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return (int) pow(2, $retries - 1); |
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} |
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|
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/** |
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* @param RequestInterface $request |
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* @param array $options |
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* |
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* @return PromiseInterface |
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*/ |
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public function __invoke(RequestInterface $request, array $options) |
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{ |
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if (!isset($options['retries'])) { |
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$options['retries'] = 0; |
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} |
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|
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$fn = $this->nextHandler; |
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return $fn($request, $options) |
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->then( |
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$this->onFulfilled($request, $options), |
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$this->onRejected($request, $options) |
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); |
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} |
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|
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/** |
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* Execute fulfilled closure |
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* |
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* @return mixed |
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*/ |
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private function onFulfilled(RequestInterface $req, array $options) |
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{ |
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return function ($value) use ($req, $options) { |
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if (!call_user_func( |
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$this->decider, |
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$options['retries'], |
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$req, |
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$value, |
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null |
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)) { |
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return $value; |
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} |
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return $this->doRetry($req, $options, $value); |
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}; |
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} |
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|
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/** |
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* Execute rejected closure |
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* |
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* @return callable |
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*/ |
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private function onRejected(RequestInterface $req, array $options) |
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{ |
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return function ($reason) use ($req, $options) { |
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if (!call_user_func( |
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$this->decider, |
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$options['retries'], |
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$req, |
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null, |
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$reason |
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)) { |
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return \GuzzleHttp\Promise\rejection_for($reason); |
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} |
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return $this->doRetry($req, $options); |
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}; |
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} |
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|
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/** |
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* @return self |
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*/ |
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private function doRetry(RequestInterface $request, array $options, ResponseInterface $response = null) |
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{ |
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$options['delay'] = call_user_func($this->delay, ++$options['retries'], $response); |
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|
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return $this($request, $options); |
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} |
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} |
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|
