RetryMiddleware.php

<?php
namespace GuzzleHttp;
 
use GuzzleHttp\Promise\PromiseInterface;
use GuzzleHttp\Promise\RejectedPromise;
use GuzzleHttp\Psr7;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;
 
class RetryMiddleware
{
    private $nextHandler;
 
    private $decider;
 
    private $delay;
 
    public function __construct(
        callable $decider,
        callable $nextHandler,
        callable $delay = null
    ) {
        $this->decider = $decider;
        $this->nextHandler = $nextHandler;
        $this->delay = $delay ?: __CLASS__ . '::exponentialDelay';
    }
 
    public static function exponentialDelay($retries)
    {
        return (int) pow(2, $retries - 1) * 1000;
    }
 
    public function __invoke(RequestInterface $request, array $options)
    {
        if (!isset($options['retries'])) {
            $options['retries'] = 0;
        }
 
        $fn = $this->nextHandler;
        return $fn($request, $options)
            ->then(
                $this->onFulfilled($request, $options),
                $this->onRejected($request, $options)
            );
    }
 
    private function onFulfilled(RequestInterface $req, array $options)
    {
        return function ($value) use ($req, $options) {
            if (!call_user_func(
                $this->decider,
                $options['retries'],
                $req,
                $value,
                null
            )) {
                return $value;
            }
            return $this->doRetry($req, $options, $value);
        };
    }
 
    private function onRejected(RequestInterface $req, array $options)
    {
        return function ($reason) use ($req, $options) {
            if (!call_user_func(
                $this->decider,
                $options['retries'],
                $req,
                null,
                $reason
            )) {
                return \GuzzleHttp\Promise\rejection_for($reason);
            }
            return $this->doRetry($req, $options);
        };
    }
 
    private function doRetry(RequestInterface $request, array $options, ResponseInterface $response = null)
    {
        $options['delay'] = call_user_func($this->delay, ++$options['retries'], $response);
 
        return $this($request, $options);
    }
}