# Lifespan Events { #lifespan-events }

You can define logic (code) that should be executed before the application **starts up**. This means that this code will be executed **once**, **before** the application **starts receiving requests**.

The same way, you can define logic (code) that should be executed when the application is **shutting down**. In this case, this code will be executed **once**, **after** having handled possibly **many requests**.

1. The client looks for a compatible idle daemon. If there isn't one, it starts a new daemon.
2. The client connects to the idle daemon and sends it a request to do some work. If the daemon is no longer running, the client starts again.
3. If the daemon is not able to run the request, for example it is already running a request or is shutting down, it rejects the request. The client starts again.

@app.get("/items/{item_id}")
async def read_items(item_id: str):
    return items[item_id]


def test_read_items():
    # Before the lifespan starts, "items" is still empty
    assert items == {}

    with TestClient(app) as client:
        # Inside the "with TestClient" block, the lifespan starts and items added
        assert items == {"foo": {"name": "Fighters"}, "bar": {"name": "Tenders"}}

        response = client.get("/items/foo")

      field = value
      delegate.dispatcher = value.wrap()
    }

  val port: Int
    get() {
      before() // This implicitly starts the delegate.
      return delegate.port
    }

  val hostName: String
    get() {
      before() // This implicitly starts the delegate.
      return delegate.hostName
    }

  var protocolNegotiationEnabled: Boolean by delegate::protocolNegotiationEnabled

    /**
     * Called when a processing phase starts.
     *
     * @param phase the phase name (e.g., "intent", "search", "evaluate", "fetch", "answer")
     * @param message a human-readable message describing what's happening
     */
    void onPhaseStart(String phase, String message);

    /**
     * Called when a processing phase starts with additional context data.
     *

    @Timeout(5)
    public void testSessionLifecycle() throws Exception {
        SmbSessionImpl session = new SmbSessionImpl(mockContext, "testhost", "testdomain", mockTransport);

        // Test initial state - session starts with usage count > 0 due to transport.acquire()
        assertTrue(session.isInUse(), "New session should be in use due to transport acquisition");

        // Test additional acquire
        session.acquire();

  * It currently requires a JVM and will download the Gradle distribution if it is not already present.
* A Gradle version installed on the system
  * This starts the [Gradle Launcher](https://blog.gradle.org/how-gradle-works-1#local-gradle-distribution-in-cli), which itself requires a JVM
* The [Gradle Tooling API client](https://docs.gradle.org/8.8/userguide/third_party_integration.html#embedding)

	md5hex := getMD5Hash(textData)
	sha256hex := ""

	// benchmark utility which helps obtain number of allocations and bytes allocated per ops.
	b.ReportAllocs()
	// the actual benchmark for PutObject starts here. Reset the benchmark timer.

	for i := 0; b.Loop(); i++ {
		// insert the object.
		objInfo, err := obj.PutObject(b.Context(), bucket, "object"+strconv.Itoa(i),

`Depends()` erhält einen `scope`-Parameter, der sein kann:

* `"function"`: startet die Abhängigkeit vor der *Pfadoperation-Funktion*, die den Request bearbeitet, beendet die Abhängigkeit nach dem Ende der *Pfadoperation-Funktion*, aber **bevor** die Response an den Client zurückgesendet wird. Die Abhängigkeitsfunktion wird also **um** die *Pfadoperation-**Funktion*** **herum** ausgeführt.

## `fastapi dev` { #fastapi-dev }

Das Ausführen von `fastapi dev` startet den Entwicklermodus.