www.aleph1.co.uk Git - yaffs-website/blob - vendor/guzzlehttp/guzzle/src/RetryMiddleware.php

   1 <?php
   2 namespace GuzzleHttp;
   3
   4 use GuzzleHttp\Promise\PromiseInterface;
   5 use GuzzleHttp\Promise\RejectedPromise;
   6 use GuzzleHttp\Psr7;
   7 use Psr\Http\Message\RequestInterface;
   8 use Psr\Http\Message\ResponseInterface;
   9
  10 /**
  11  * Middleware that retries requests based on the boolean result of
  12  * invoking the provided "decider" function.
  13  */
  14 class RetryMiddleware
  15 {
  16     /** @var callable  */
  17     private $nextHandler;
  18
  19     /** @var callable */
  20     private $decider;
  21
  22     /**
  23      * @param callable $decider     Function that accepts the number of retries,
  24      *                              a request, [response], and [exception] and
  25      *                              returns true if the request is to be
  26      *                              retried.
  27      * @param callable $nextHandler Next handler to invoke.
  28      * @param callable $delay       Function that accepts the number of retries
  29      *                              and [response] and returns the number of
  30      *                              milliseconds to delay.
  31      */
  32     public function __construct(
  33         callable $decider,
  34         callable $nextHandler,
  35         callable $delay = null
  36     ) {
  37         $this->decider = $decider;
  38         $this->nextHandler = $nextHandler;
  39         $this->delay = $delay ?: __CLASS__ . '::exponentialDelay';
  40     }
  41
  42     /**
  43      * Default exponential backoff delay function.
  44      *
  45      * @param $retries
  46      *
  47      * @return int
  48      */
  49     public static function exponentialDelay($retries)
  50     {
  51         return (int) pow(2, $retries - 1);
  52     }
  53
  54     /**
  55      * @param RequestInterface $request
  56      * @param array            $options
  57      *
  58      * @return PromiseInterface
  59      */
  60     public function __invoke(RequestInterface $request, array $options)
  61     {
  62         if (!isset($options['retries'])) {
  63             $options['retries'] = 0;
  64         }
  65
  66         $fn = $this->nextHandler;
  67         return $fn($request, $options)
  68             ->then(
  69                 $this->onFulfilled($request, $options),
  70                 $this->onRejected($request, $options)
  71             );
  72     }
  73
  74     private function onFulfilled(RequestInterface $req, array $options)
  75     {
  76         return function ($value) use ($req, $options) {
  77             if (!call_user_func(
  78                 $this->decider,
  79                 $options['retries'],
  80                 $req,
  81                 $value,
  82                 null
  83             )) {
  84                 return $value;
  85             }
  86             return $this->doRetry($req, $options, $value);
  87         };
  88     }
  89
  90     private function onRejected(RequestInterface $req, array $options)
  91     {
  92         return function ($reason) use ($req, $options) {
  93             if (!call_user_func(
  94                 $this->decider,
  95                 $options['retries'],
  96                 $req,
  97                 null,
  98                 $reason
  99             )) {
 100                 return \GuzzleHttp\Promise\rejection_for($reason);
 101             }
 102             return $this->doRetry($req, $options);
 103         };
 104     }
 105
 106     private function doRetry(RequestInterface $request, array $options, ResponseInterface $response = null)
 107     {
 108         $options['delay'] = call_user_func($this->delay, ++$options['retries'], $response);
 109
 110         return $this($request, $options);
 111     }
 112 }