participant client as Client
participant handler as Exception handler
participant dep as Dep with yield
participant operation as Path Operation
participant tasks as Background tasks

    Note over client,operation: Can raise exceptions, including HTTPException
    client ->> dep: Start request
    Note over dep: Run code up to yield
    opt raise Exception
        dep -->> handler: Raise Exception

		opts.Storage = true
		opts.OS = true
		// Older mc - cannot deal with more types...
	}
	return opts, err
}

// TraceHandler - POST /minio/admin/v3/trace
// ----------
// The handler sends http trace to the connected HTTP client.
func (a adminAPIHandlers) TraceHandler(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	// Validate request signature.

import org.codelibs.core.io.FileUtil;
import org.codelibs.fess.crawler.exception.CrawlerSystemException;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.ServerConnector;
import org.eclipse.jetty.server.handler.DefaultHandler;
import org.eclipse.jetty.server.handler.ResourceHandler;
import org.eclipse.jetty.util.resource.ResourceFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

{* ../../docs_src/events/tutorial001_py310.py hl[8] *}

Bu durumda `startup` event handler fonksiyonu, "database" öğesini (sadece bir `dict`) bazı değerlerle başlatır.

Birden fazla event handler fonksiyonu ekleyebilirsiniz.

Ve tüm `startup` event handler’ları tamamlanmadan uygulamanız request almaya başlamaz.

### `shutdown` eventi { #shutdown-event }

participant client as Client
participant handler as Exception handler
participant dep as Dep with yield
participant operation as Path Operation
participant tasks as Background tasks

    Note over client,operation: Can raise exceptions, including HTTPException
    client ->> dep: Start request
    Note over dep: Run code up to yield
    opt raise Exception
        dep -->> handler: Raise Exception

    Note over dep: Executar código até o yield
    opt lançar Exceção
        dep -->> handler: lançar Exceção
        handler -->> client: resposta de erro HTTP
    end
    dep ->> operation: Executar dependência, e.g. sessão de BD
    opt raise
        operation -->> dep: Lançar exceção (e.g. HTTPException)
        opt handle
            dep -->> dep: Pode capturar exceções, lançar uma nova HTTPException, lançar outras exceções

	if err != nil {
		err = msgp.WrapError(err, "DeadlineMS")
		return
	}
	{
		var zb0002 uint8
		zb0002, err = dc.ReadUint8()
		if err != nil {
			err = msgp.WrapError(err, "Handler")
			return
		}
		z.Handler = HandlerID(zb0002)
	}
	{
		var zb0003 uint8
		zb0003, err = dc.ReadUint8()
		if err != nil {
			err = msgp.WrapError(err, "Op")
			return
		}
		z.Op = Op(zb0003)
	}
	{

* cookie parameter
* header parameter
* form parameter
* function parameter

* event
* startup event
* server'ın startup'ı
* shutdown event
* lifespan event

* handler
* event handler
* exception handler
* handle etmek

* model
* Pydantic model
* data model
* database model
* form model
* model object

* class
* base class
* parent class
* subclass

## Zugriff auf den Requestbody in einem Exceptionhandler { #accessing-the-request-body-in-an-exception-handler }

/// tip | Tipp

Um dasselbe Problem zu lösen, ist es wahrscheinlich viel einfacher, den `body` in einem benutzerdefinierten Handler für `RequestValidationError` zu verwenden ([Fehlerbehandlung](../tutorial/handling-errors.md#use-the-requestvalidationerror-body)).

        final EventInfo event = new EventInfo();
        event.name = "test_event";
        coordinatorHelper.dispatchEvent(event);

        // Second handler should still be called even if first throws
        assertTrue(secondCalled.get());
    }

    @Test
    public void test_dispatchEvent_eventData() {