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<?php
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namespace GuzzleHttp;
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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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 * 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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    /** @var callable */
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    private $decider;
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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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     * Default exponential backoff delay function.
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     *
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     * @param $retries
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     *
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     * @return int
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     */
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    public static function exponentialDelay($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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     * @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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        $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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    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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    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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                $reason
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            )) {
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                return new RejectedPromise($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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    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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        return $this($request, $options);
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    }
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}