promise.php

См. документацию.

<?php

 
namespace Bitrix\Main\Web\Http;
 
use Http\Promise\Promise as PromiseInterface;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;
 
abstract class Promise implements PromiseInterface
{
    protected string $state = self::PENDING;

    protected $onFulfilled = [];

    protected $onRejected = [];
 
    protected $handler;
 
    protected Queue $queue;
 
    protected ResponseInterface $response;
 
    protected ?ClientException $exception = null;
 
    protected string $id = '';
 
    public function __construct($handler, Queue $queue)
    {
        $this->handler = $handler;
        $this->queue = $queue;
    }

    public function then(callable $onFulfilled = null, callable $onRejected = null)
    {
        $state = $this->getState();
 
        if ($onFulfilled)
        {
            if ($state == self::PENDING)
            {
                $this->onFulfilled[] = $onFulfilled;
            }
            elseif ($state == self::FULFILLED)
            {
                call_user_func($onFulfilled, $this->response);
            }
        }
 
        if ($onRejected)
        {
            if ($state == self::PENDING)
            {
                $this->onRejected[] = $onRejected;
            }
            elseif ($state == self::REJECTED)
            {
                $this->exception = call_user_func($onRejected, $this->exception);
            }
        }
 
        return new static($this->handler, $this->queue);
    }

    public function getState()
    {
        return $this->state;
    }

    public function wait($unwrap = true)
    {
        $this->queue->wait($this);
 
        if ($unwrap)
        {
            if ($this->getState() == self::REJECTED)
            {
                throw $this->exception;
            }
 
            return $this->response;
        }
 
        return null;
    }

    public function fulfill(ResponseInterface $response): void
    {
        $this->state = self::FULFILLED;
        $this->response = $response;
 
        while (!empty($this->onFulfilled))
        {
            $callback = array_shift($this->onFulfilled);
            $response = call_user_func($callback, $this->response);
 
            if ($response instanceof ResponseInterface)
            {
                $this->response = $response;
            }
        }
    }

    public function reject(ClientException $exception): void
    {
        $this->state = self::REJECTED;
        $this->exception = $exception;
 
        while (!empty($this->onRejected))
        {
            $callback = array_shift($this->onRejected);
            try
            {
                $exception = call_user_func($callback, $exception);
                $this->exception = $exception;
            }
            catch (ClientException $exception)
            {
                $this->exception = $exception;
            }
        }
    }

    public function getRequest(): RequestInterface
    {
        return $this->handler->getRequest();
    }

    public function getId(): string
    {
        return $this->id;
    }
 
    abstract public function getHandler();
}