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<?php
namespace GuzzleHttp;
use GuzzleHttp\Event\BeforeEvent;
use GuzzleHttp\Event\ErrorEvent;
use GuzzleHttp\Event\CompleteEvent;
use GuzzleHttp\Event\EndEvent;
use GuzzleHttp\Exception\StateException;
use GuzzleHttp\Exception\RequestException;
use GuzzleHttp\Message\FutureResponse;
use GuzzleHttp\Message\MessageFactoryInterface;
use GuzzleHttp\Ring\Future\FutureInterface;
/**
* Responsible for transitioning requests through lifecycle events.
*/
class RequestFsm
{
private $handler;
private $mf;
private $maxTransitions;
public function __construct(
callable $handler,
MessageFactoryInterface $messageFactory,
$maxTransitions = 200
) {
$this->mf = $messageFactory;
$this->maxTransitions = $maxTransitions;
$this->handler = $handler;
}
/**
* Runs the state machine until a terminal state is entered or the
* optionally supplied $finalState is entered.
*
* @param Transaction $trans Transaction being transitioned.
*
* @throws \Exception if a terminal state throws an exception.
*/
public function __invoke(Transaction $trans)
{
$trans->_transitionCount = 0;
if (!$trans->state) {
$trans->state = 'before';
}
transition:
if (++$trans->_transitionCount > $this->maxTransitions) {
throw new StateException("Too many state transitions were "
. "encountered ({$trans->_transitionCount}). This likely "
. "means that a combination of event listeners are in an "
. "infinite loop.");
}
switch ($trans->state) {
case 'before': goto before;
case 'complete': goto complete;
case 'error': goto error;
case 'retry': goto retry;
case 'send': goto send;
case 'end': goto end;
default: throw new StateException("Invalid state: {$trans->state}");
}
before: {
try {
$trans->request->getEmitter()->emit('before', new BeforeEvent($trans));
$trans->state = 'send';
if ((bool) $trans->response) {
$trans->state = 'complete';
}
} catch (\Exception $e) {
$trans->state = 'error';
$trans->exception = $e;
}
goto transition;
}
complete: {
try {
if ($trans->response instanceof FutureInterface) {
// Futures will have their own end events emitted when
// dereferenced.
return;
}
$trans->state = 'end';
$trans->response->setEffectiveUrl($trans->request->getUrl());
$trans->request->getEmitter()->emit('complete', new CompleteEvent($trans));
} catch (\Exception $e) {
$trans->state = 'error';
$trans->exception = $e;
}
goto transition;
}
error: {
try {
// Convert non-request exception to a wrapped exception
$trans->exception = RequestException::wrapException(
$trans->request, $trans->exception
);
$trans->state = 'end';
$trans->request->getEmitter()->emit('error', new ErrorEvent($trans));
// An intercepted request (not retried) transitions to complete
if (!$trans->exception && $trans->state !== 'retry') {
$trans->state = 'complete';
}
} catch (\Exception $e) {
$trans->state = 'end';
$trans->exception = $e;
}
goto transition;
}
retry: {
$trans->retries++;
$trans->response = null;
$trans->exception = null;
$trans->state = 'before';
goto transition;
}
send: {
$fn = $this->handler;
$trans->response = FutureResponse::proxy(
$fn(RingBridge::prepareRingRequest($trans)),
function ($value) use ($trans) {
RingBridge::completeRingResponse($trans, $value, $this->mf, $this);
$this($trans);
return $trans->response;
}
);
return;
}
end: {
$trans->request->getEmitter()->emit('end', new EndEvent($trans));
// Throw exceptions in the terminal event if the exception
// was not handled by an "end" event listener.
if ($trans->exception) {
if (!($trans->exception instanceof RequestException)) {
$trans->exception = RequestException::wrapException(
$trans->request, $trans->exception
);
}
throw $trans->exception;
}
}
}
}
|