| 1: | <?php |
| 2: | |
| 3: | declare(strict_types=1); |
| 4: | |
| 5: | /** |
| 6: | * This file is part of the Nexus MCP SDK package. |
| 7: | * |
| 8: | * (c) 2026 John Paul E. Balandan, CPA <paulbalandan@gmail.com> |
| 9: | * |
| 10: | * For the full copyright and license information, please view |
| 11: | * the LICENSE file that was distributed with this source code. |
| 12: | */ |
| 13: | |
| 14: | namespace Nexus\Mcp\Client\Subscription; |
| 15: | |
| 16: | use Amp\Future; |
| 17: | use Nexus\Mcp\Client\Exception\SubscriptionClosedException; |
| 18: | use Nexus\Mcp\Core\Exception\RemoteCallFailedException; |
| 19: | use Nexus\Mcp\Core\Schema\RequestId; |
| 20: | use Nexus\Mcp\Core\Schema\Result\SubscriptionsListenResult; |
| 21: | |
| 22: | /** |
| 23: | * An open `subscriptions/listen` stream. Ends when the caller closes it or the server tears it down. |
| 24: | * A supervised transport re-opens it against each replacement peer under the same subscription id, |
| 25: | * so neither the id nor this object is spent by a restart. |
| 26: | */ |
| 27: | final class SubscriptionStream |
| 28: | { |
| 29: | private bool $closed = false; |
| 30: | |
| 31: | /** |
| 32: | * @param Future<SubscriptionsListenResult> $outcome |
| 33: | * @param \Closure(): void $onClose |
| 34: | * |
| 35: | * @internal |
| 36: | */ |
| 37: | public function __construct( |
| 38: | public readonly RequestId $subscriptionId, |
| 39: | private readonly Future $outcome, |
| 40: | private readonly \Closure $onClose, |
| 41: | ) { |
| 42: | } |
| 43: | |
| 44: | /** |
| 45: | * Stops the stream, telling the server the subscription is over. Subsequent calls are no-ops. |
| 46: | */ |
| 47: | public function close(): void |
| 48: | { |
| 49: | if ($this->closed) { |
| 50: | return; |
| 51: | } |
| 52: | |
| 53: | $this->closed = true; |
| 54: | ($this->onClose)(); |
| 55: | } |
| 56: | |
| 57: | /** |
| 58: | * Blocks until the server tears the subscription down of its own accord. A peer that dies under |
| 59: | * supervision does not settle this: the wait resumes against the replacement. |
| 60: | * |
| 61: | * @throws RemoteCallFailedException |
| 62: | * @throws SubscriptionClosedException |
| 63: | */ |
| 64: | public function await(): SubscriptionsListenResult |
| 65: | { |
| 66: | if ($this->closed) { |
| 67: | // The spec answers an abrupt close with nothing, so this response can never arrive and |
| 68: | // awaiting it would park the caller for good. |
| 69: | throw new SubscriptionClosedException($this->subscriptionId); |
| 70: | } |
| 71: | |
| 72: | return $this->outcome->await(); |
| 73: | } |
| 74: | } |
| 75: |