phpbotgram

Concrete subclasses implement __invoke to participate in the (handler, event, data) chain that wraps a registered Telegram update handler: call $handler($event, $data) to delegate to the next link (another middleware or, at the chain's tail, the resolved handler). Skipping that call short-circuits the chain — useful for throttling, auth gates, and cache hits.

The $event parameter is typed as object rather than TelegramObject because the same middleware pipeline transports synthetic events too — notably ErrorEvent, which deliberately does NOT extend TelegramObject (see Types/ErrorEvent.php for the rationale). Concrete middlewares may declare a narrower type via covariance-safe instanceof checks; PHPStan level 9 still flags wider unsafe accesses.

Note: dispatcher middlewares are intentionally distinct from request middlewares (Client/Session/Middleware/BaseRequestMiddleware). Request middlewares wrap outgoing API calls (Bot, TelegramMethod, ?int $timeout); dispatcher middlewares wrap incoming update routing (object, kwargs).

The contextual $data bag (bot, event_context, FSM state, …) MAY be mutated before delegating — CallableObject will then bind only the keys each concrete handler declares.