Events

The listener accepts an optional Psr\EventDispatcher\EventDispatcherInterface via its constructor. When one is provided, three events are dispatched in well-defined positions of the accept() flow. When the dispatcher argument is null the events are not emitted at all — there is no NullEventDispatcher instantiated internally.

All three event classes live under PhpOpcua\Client\ExtReverseConnect\Event\, are final readonly, and carry only the data needed by listeners.

ReverseHelloReceived

final readonly class ReverseHelloReceived
{
    public function __construct(
        public ReverseHelloMessage $message,
    ) {}
}

Dispatched immediately after a successful frame decode and before the validator runs. Listeners attached here observe every parseable RHE — including the ones that will then be rejected. Useful for diagnostics and audit logging.

ReverseConnectAccepted

final readonly class ReverseConnectAccepted
{
    public function __construct(
        public ReverseHelloMessage $message,
    ) {}
}

Dispatched after the validator silently approves the message and before accept() returns the session. By the time a handler runs, the socket is still owned by the listener; the ReverseConnectSession is yielded immediately afterwards.

ReverseConnectRejected

final readonly class ReverseConnectRejected
{
    public function __construct(
        public ReverseHelloMessage $message,
        public string $reason,
    ) {}
}

Dispatched when the validator rejects the message — exactly once, just before ReverseConnectRejectedException is raised and before the socket is closed. $reason is the same string the exception carries in its message, so a single handler is enough to log structured context without duplicating logic.

A frame that fails to decode does not dispatch this event — parse failures raise ReverseHelloParseException directly. Listen on both ReverseHelloReceived (parseable) and the exception path (parse failures) if you need a complete trace.

Subscription pattern

use Psr\EventDispatcher\EventDispatcherInterface;
use PhpOpcua\Client\ExtReverseConnect\Event\ReverseConnectAccepted;
use PhpOpcua\Client\ExtReverseConnect\Event\ReverseConnectRejected;
use PhpOpcua\Client\ExtReverseConnect\Event\ReverseHelloReceived;
use PhpOpcua\Client\ExtReverseConnect\ReverseConnectListener;
use PhpOpcua\Client\ExtReverseConnect\ReverseHelloValidator;

$dispatcher = new MyDispatcher();   // any PSR-14 implementation

$listener = new ReverseConnectListener(
    bindHost: '0.0.0.0',
    bindPort: 4841,
    validator: new ReverseHelloValidator(['urn:gateway:42']),
    dispatcher: $dispatcher,
);

How the dispatcher routes those classes to handlers is the dispatcher's business — the package ships no provider, no listener registry, and no global state. Any PSR-14-compatible implementation (symfony/event-dispatcher, league/event, in-house, etc.) works.

Ordering guarantees

For a single accept() call:

The listener emits no event for its own bind/close operations; if you need that, hook into your logger output (the listener logs Reverse-connect listener bound at INFO after listen() succeeds).