<?php
namespace Aws\S3\Parser;
use Aws\Api\ErrorParser\XmlErrorParser;
use Aws\Api\Parser\AbstractParser;
use Aws\Api\Parser\Exception\ParserException;
use Aws\Api\Service;
use Aws\Api\StructureShape;
use Aws\CommandInterface;
use Aws\Exception\AwsException;
use Aws\ResultInterface;
use GuzzleHttp\Psr7\Utils;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\StreamInterface;
/**
* Custom S3 parser on top of the S3 protocol parser
* for handling specific S3 parsing scenarios.
*
* @internal
*/
final class S3Parser extends AbstractParser
{
/** @var AbstractParser */
private $protocolParser;
/** @var XmlErrorParser */
private $errorParser;
/** @var string */
private $exceptionClass;
/** @var array */
private $s3ResultMutators;
/**
* @param AbstractParser $protocolParser
* @param XmlErrorParser $errorParser
* @param Service $api
* @param string $exceptionClass
*/
public function __construct(
AbstractParser $protocolParser,
XmlErrorParser $errorParser,
Service $api,
string $exceptionClass = AwsException::class
)
{
parent::__construct($api);
$this->protocolParser = $protocolParser;
$this->errorParser = $errorParser;
$this->exceptionClass = $exceptionClass;
$this->s3ResultMutators = [];
}
/**
* Parses a S3 response.
*
* @param CommandInterface $command The command that originated the request.
* @param ResponseInterface $response The response received from the service.
*
* @return ResultInterface|null
*/
public function __invoke(
CommandInterface $command,
ResponseInterface $response
):? ResultInterface
{
// Check first if the response is an error
$this->parse200Error($command, $response);
try {
$parseFn = $this->protocolParser;
$result = $parseFn($command, $response);
} catch (ParserException $e) {
// Parsing errors will be considered retryable.
throw new $this->exceptionClass(
"Error parsing response for {$command->getName()}:"
. " AWS parsing error: {$e->getMessage()}",
$command,
['connection_error' => true, 'exception' => $e],
$e
);
}
return $this->executeS3ResultMutators($result, $command, $response);
}
/**
* Tries to parse a 200 response as an error from S3.
* If the parsed result contains a code and message then that means an error
* was found, and hence an exception is thrown with that error.
*
* @param CommandInterface $command
* @param ResponseInterface $response
*
* @return void
*/
private function parse200Error(
CommandInterface $command,
ResponseInterface $response
): void
{
// This error parsing should be just for 200 error responses
// and operations where its output shape does not have a streaming
// member.
if (200 !== $response->getStatusCode()
|| !$this->shouldBeConsidered200Error($command->getName())) {
return;
}
// To guarantee we try the error parsing just for an Error xml response.
if (!$this->isFirstRootElementError($response->getBody())) {
return;
}
try {
$errorParserFn = $this->errorParser;
$parsedError = $errorParserFn($response, $command);
} catch (ParserException $e) {
// Parsing errors will be considered retryable.
$parsedError = [
'code' => 'ConnectionError',
'message' => "An error connecting to the service occurred"
. " while performing the " . $command->getName()
. " operation."
];
}
if (isset($parsedError['code']) && isset($parsedError['message'])) {
throw new $this->exceptionClass(
$parsedError['message'],
$command,
[
'connection_error' => true,
'code' => $parsedError['code'],
'message' => $parsedError['message']
]
);
}
}
/**
* Checks if a specific operation should be considered
* a s3 200 error. Operations where any of its output members
* has a streaming or httpPayload trait should be not considered.
*
* @param $commandName
*
* @return bool
*/
private function shouldBeConsidered200Error($commandName): bool
{
$operation = $this->api->getOperation($commandName);
$output = $operation->getOutput();
foreach ($output->getMembers() as $_ => $memberProps) {
if (!empty($memberProps['eventstream']) || !empty($memberProps['streaming'])) {
return false;
}
}
return true;
}
/**
* Checks if the root element of the response body is "Error", which is
* when we should try to parse an error from a 200 response from s3.
* It is recommended to make sure the stream given is seekable, otherwise
* the rewind call will cause a user warning.
*
* @param StreamInterface $responseBody
*
* @return bool
*/
private function isFirstRootElementError(StreamInterface $responseBody): bool
{
static $pattern = '/<\?xml version="1\.0" encoding="UTF-8"\?>\s*<Error>/';
// To avoid performance overhead in large streams
$reducedBodyContent = $responseBody->read(64);
$foundErrorElement = preg_match($pattern, $reducedBodyContent);
// A rewind is needed because the stream is partially or entirely consumed
// in the previous read operation.
$responseBody->rewind();
return $foundErrorElement;
}
/**
* Execute mutator implementations over a result.
* Mutators are logics that modifies a result.
*
* @param ResultInterface $result
* @param CommandInterface $command
* @param ResponseInterface $response
*
* @return ResultInterface
*/
private function executeS3ResultMutators(
ResultInterface $result,
CommandInterface $command,
ResponseInterface $response
): ResultInterface
{
foreach ($this->s3ResultMutators as $mutator) {
$result = $mutator($result, $command, $response);
}
return $result;
}
/**
* Adds a mutator into the list of mutators.
*
* @param string $mutatorName
* @param S3ResultMutator $s3ResultMutator
* @return void
*/
public function addS3ResultMutator(
string $mutatorName,
S3ResultMutator $s3ResultMutator
): void
{
if (isset($this->s3ResultMutators[$mutatorName])) {
trigger_error(
"The S3 Result Mutator {$mutatorName} already exists!",
E_USER_WARNING
);
return;
}
$this->s3ResultMutators[$mutatorName] = $s3ResultMutator;
}
/**
* Removes a mutator from the mutator list.
*
* @param string $mutatorName
* @return void
*/
public function removeS3ResultMutator(string $mutatorName): void
{
if (!isset($this->s3ResultMutators[$mutatorName])) {
trigger_error(
"The S3 Result Mutator {$mutatorName} does not exist!",
E_USER_WARNING
);
return;
}
unset($this->s3ResultMutators[$mutatorName]);
}
/**
* Returns the list of result mutators available.
*
* @return array
*/
public function getS3ResultMutators(): array
{
return $this->s3ResultMutators;
}
public function parseMemberFromStream(
StreamInterface $stream,
StructureShape $member,
$response
)
{
return $this->protocolParser->parseMemberFromStream(
$stream,
$member,
$response
);
}
}
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