<?php
  /**
   * Copyright 2010-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License").
   * You may not use this file except in compliance with the License.
   * A copy of the License is located at
   *
   * http://aws.amazon.com/apache2.0
   *
   * or in the "license" file accompanying this file. This file is distributed
   * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
   * express or implied. See the License for the specific language governing
   * permissions and limitations under the License.
   */
  
  namespace Aws\S3;
  
  use Guzzle\Http\Exception\HttpException;
  use Guzzle\Http\Message\RequestInterface;
  use Guzzle\Http\Message\EntityEnclosingRequestInterface;
  use Guzzle\Http\Message\Response;
  use Guzzle\Plugin\Backoff\BackoffStrategyInterface;
  use Guzzle\Plugin\Backoff\AbstractBackoffStrategy;
  
  /**
   * Custom S3 exponential backoff checking use to retry 400 responses containing the following reason phrase:
   * "Your socket connection to the server was not read from or written to within the timeout period.".
   * This error has been reported as intermittent/random, and in most cases, seems to occur during the middle of a
   * transfer. This plugin will attempt to retry these failed requests, and if using a local file, will clear the
   * stat cache of the file and set a new content-length header on the upload.
   */
  class SocketTimeoutChecker extends AbstractBackoffStrategy
  {
      const ERR = 'Your socket connection to the server was not read from or written to within the timeout period';
  
      /**
       * {@inheridoc}
       */
      public function __construct(BackoffStrategyInterface $next = null)
      {
          if ($next) {
              $this->setNext($next);
          }
      }
  
      /**
       * {@inheridoc}
       */
      public function makesDecision()
      {
          return true;
      }
  
      /**
       * {@inheritdoc}
       */
      protected function getDelay(
          $retries,
          RequestInterface $request,
          Response $response = null,
          HttpException $e = null
      ) {
          if ($response
              && $response->getStatusCode() == 400
              && strpos($response->getBody(), self::ERR)
          ) {
              // Check if the request is sending a local file, and if so, clear the stat cache and recalculate the size.
              if ($request instanceof EntityEnclosingRequestInterface) {
                  if ($request->getBody()->getWrapper() == 'plainfile') {
                      $filename = $request->getBody()->getUri();
                      // Clear the cache so that we send accurate file sizes
                      clearstatcache(true, $filename);
                      $length = filesize($filename);
                      $request->getBody()->setSize($length);
                      $request->setHeader('Content-Length', $length);
                  }
              }
  
              return true;
          }
      }
  }