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<?php |
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namespace Dudlewebs\WPMCS\s3\Aws; |
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|
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use Dudlewebs\WPMCS\s3\Aws\Api\Service; |
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use Dudlewebs\WPMCS\s3\Psr\Http\Message\RequestInterface; |
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/** |
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* @internal Middleware that auto fills parameters with `idempotencyToken` trait |
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*/ |
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class IdempotencyTokenMiddleware |
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{ |
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/** @var Service */ |
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private $service; |
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/** @var string */ |
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private $bytesGenerator; |
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/** @var callable */ |
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private $nextHandler; |
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/** |
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* Creates a middleware that populates operation parameter |
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* with trait 'idempotencyToken' enabled with a random UUIDv4 |
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* |
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* One of following functions needs to be available |
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* in order to generate random bytes used for UUID |
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* (SDK will attempt to utilize function in following order): |
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* - random_bytes (requires PHP 7.0 or above) |
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* - openssl_random_pseudo_bytes (requires 'openssl' module enabled) |
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* - mcrypt_create_iv (requires 'mcrypt' module enabled) |
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* |
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* You may also supply a custom bytes generator as an optional second |
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* parameter. |
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* |
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* @param \Aws\Api\Service $service |
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* @param callable|null $bytesGenerator |
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* |
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* @return callable |
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*/ |
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public static function wrap(Service $service, callable $bytesGenerator = null) |
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{ |
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return function (callable $handler) use($service, $bytesGenerator) { |
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return new self($handler, $service, $bytesGenerator); |
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}; |
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} |
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public function __construct(callable $nextHandler, Service $service, callable $bytesGenerator = null) |
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{ |
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$this->bytesGenerator = $bytesGenerator ?: $this->findCompatibleRandomSource(); |
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$this->service = $service; |
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$this->nextHandler = $nextHandler; |
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} |
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public function __invoke(CommandInterface $command, RequestInterface $request = null) |
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{ |
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$handler = $this->nextHandler; |
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if ($this->bytesGenerator) { |
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$operation = $this->service->getOperation($command->getName()); |
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$members = $operation->getInput()->getMembers(); |
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foreach ($members as $member => $value) { |
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if ($value['idempotencyToken']) { |
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$bytes = \call_user_func($this->bytesGenerator, 16); |
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// populating UUIDv4 only when the parameter is not set |
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$command[$member] = $command[$member] ?: $this->getUuidV4($bytes); |
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// only one member could have the trait enabled |
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break; |
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} |
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} |
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} |
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return $handler($command, $request); |
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} |
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/** |
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* This function generates a random UUID v4 string, |
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* which is used as auto filled token value. |
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* |
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* @param string $bytes 16 bytes of pseudo-random bytes |
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* @return string |
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* More information about UUID v4, see: |
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* https://en.wikipedia.org/wiki/Universally_unique_identifier#Version_4_.28random.29 |
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* https://tools.ietf.org/html/rfc4122#page-14 |
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*/ |
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private static function getUuidV4($bytes) |
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{ |
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// set version to 0100 |
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$bytes[6] = \chr(\ord($bytes[6]) & 0xf | 0x40); |
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// set bits 6-7 to 10 |
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$bytes[8] = \chr(\ord($bytes[8]) & 0x3f | 0x80); |
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return \vsprintf('%s%s-%s-%s-%s-%s%s%s', \str_split(\bin2hex($bytes), 4)); |
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} |
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/** |
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* This function decides the PHP function used in generating random bytes. |
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* |
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* @return callable|null |
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*/ |
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private function findCompatibleRandomSource() |
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{ |
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if (\function_exists('random_bytes')) { |
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return 'random_bytes'; |
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} |
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if (\function_exists('openssl_random_pseudo_bytes')) { |
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return 'openssl_random_pseudo_bytes'; |
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} |
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if (\function_exists('mcrypt_create_iv')) { |
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return 'mcrypt_create_iv'; |
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} |
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} |
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} |
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