# 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**.

  * 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)

`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.

        session.addUserMessage("User 2");
        session.addAssistantMessage("Assistant 2");
        session.addUserMessage("User 3");
        session.addAssistantMessage("Assistant 3");

        // Trimming to 4 starts at index 2 which is user - no skip needed
        session.trimHistory(4);

        final List<ChatMessage> messages = session.getMessages();
        assertEquals(4, messages.size());

 * is by declaring that step to be the last step of the pipeline. Nevertheless, we refer to the
 * "value" of a successful step or the "result" (value or exception) of any step.
 *
 * <ol>
 *   <li>A pipeline starts at its leaf step (or steps), which is created from either a callable
 *       block or a {@link ListenableFuture}.
 *   <li>Each other step is derived from one or more input steps. At each step, zero or more objects

```console
$ pip install httpx
```

///

Import `TestClient`.

Create a `TestClient` by passing your **FastAPI** application to it.

Create functions with a name that starts with `test_` (this is standard `pytest` conventions).

Use the `TestClient` object the same way as you do with `httpx`.

You can read more about this in the [Advanced User Guide](../advanced/index.md).

## Details { #details }

The first `"/static"` refers to the sub-path this "sub-application" will be "mounted" on. So, any path that starts with `"/static"` will be handled by it.

The `directory="static"` refers to the name of the directory that contains your static files.

The `name="static"` gives it a name that can be used internally by **FastAPI**.

### Neustart nach Absturz { #restart-after-crash }

Aber in den Fällen mit wirklich schwerwiegenden Fehlern, die den laufenden **Prozess** zum Absturz bringen, benötigen Sie eine externe Komponente, die den Prozess **neu startet**, zumindest ein paar Mal ...

/// tip | Tipp

* `lang-all`: Translations
    * Use this for translations. You can normally quickly detect it by going to the "Files changed" tab in the PR and checking if the updated file(s) starts with `docs/{some lang}/docs` but not `docs/en/docs`. For example, `docs/es/docs`.