<?php
namespace Aws;
use Aws\Api\Parser\Exception\ParserException;
use GuzzleHttp\Promise;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;
/**
* Converts an HTTP handler into a Command HTTP handler.
*
* HTTP handlers have the following signature:
* function(RequestInterface $request, array $options) : PromiseInterface
*
* The promise returned form an HTTP handler must resolve to a PSR-7 response
* object when fulfilled or an error array when rejected. The error array
* can contain the following data:
*
* - exception: (required, Exception) Exception that was encountered.
* - response: (ResponseInterface) PSR-7 response that was received (if a
* response) was received.
* - connection_error: (bool) True if the error is the result of failing to
* connect.
*/
class WrappedHttpHandler
{
private $httpHandler;
private $parser;
private $errorParser;
private $exceptionClass;
/**
* @param callable $httpHandler Function that accepts a request and array
* of request options and returns a promise
* that fulfills with a response or rejects
* with an error array.
* @param callable $parser Function that accepts a response object
* and returns an AWS result object.
* @param callable $errorParser Function that parses a response object
* into AWS error data.
* @param string $exceptionClass Exception class to throw.
*/
public function __construct(
callable $httpHandler,
callable $parser,
callable $errorParser,
$exceptionClass = 'Aws\Exception\AwsException'
) {
$this->httpHandler = $httpHandler;
$this->parser = $parser;
$this->errorParser = $errorParser;
$this->exceptionClass = $exceptionClass;
}
/**
* Calls the simpler HTTP specific handler and wraps the returned promise
* with AWS specific values (e.g., a result object or AWS exception).
*
* @param CommandInterface $command Command being executed.
* @param RequestInterface $request Request to send.
*
* @return Promise\PromiseInterface
*/
public function __invoke(
CommandInterface $command,
RequestInterface $request
) {
$fn = $this->httpHandler;
return Promise\promise_for($fn($request, $command['@http'] ?: []))
->then(
function (ResponseInterface $res) use ($command, $request) {
return $this->parseResponse($command, $request, $res);
},
function ($err) use ($request, $command) {
if (is_array($err)) {
$exception = $this->parseError($err, $request, $command);
return new Promise\RejectedPromise($exception);
}
return new Promise\RejectedPromise($err);
}
);
}
/**
* @param CommandInterface $command
* @param RequestInterface $request
* @param ResponseInterface $response
*
* @return ResultInterface
*/
private function parseResponse(
CommandInterface $command,
RequestInterface $request,
ResponseInterface $response
) {
$parser = $this->parser;
$status = $response->getStatusCode();
$result = $status < 300
? $parser($command, $response)
: new Result();
$metadata = [
'statusCode' => $status,
'effectiveUri' => (string) $request->getUri(),
'headers' => []
];
// Bring headers into the metadata array.
foreach ($response->getHeaders() as $name => $values) {
$metadata['headers'][strtolower($name)] = $values[0];
}
$result['@metadata'] = $metadata;
return $result;
}
/**
* Parses a rejection into an AWS error.
*
* @param array $err Rejection error array.
* @param RequestInterface $request Request that was sent.
* @param CommandInterface $command Command being sent.
*
* @return \Exception
*/
private function parseError(
array $err,
RequestInterface $request,
CommandInterface $command
) {
if (!isset($err['exception'])) {
throw new \RuntimeException('The HTTP handler was rejected without an "exception" key value pair.');
}
$serviceError = "AWS HTTP error: " . $err['exception']->getMessage();
if (!isset($err['response'])) {
$parts = ['response' => null];
} else {
try {
$parts = call_user_func($this->errorParser, $err['response']);
$serviceError .= " {$parts['code']} ({$parts['type']}): "
. "{$parts['message']} - " . $err['response']->getBody();
} catch (ParserException $e) {
$parts = [];
$serviceError .= ' Unable to parse error information from '
. "response - {$e->getMessage()}";
}
$parts['response'] = $err['response'];
}
$parts['exception'] = $err['exception'];
$parts['request'] = $request;
$parts['connection_error'] = !empty($err['connection_error']);
return new $this->exceptionClass(
sprintf(
'Error executing "%s" on "%s"; %s',
$command->getName(),
$request->getUri(),
$serviceError
),
$command,
$parts,
$err['exception']
);
}
}
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