Podcasts:
  English:
  - author: Real Python
    author_link: https://realpython.com/
    link: https://realpython.com/podcasts/rpp/72/
    title: Starting With FastAPI and Examining Python's Import System - Episode 72
  - author: Python Bytes FM
    author_link: https://pythonbytes.fm/
    link: https://www.pythonpodcast.com/fastapi-web-application-framework-episode-259/

* How to set **validation constraints** as `maximum_length` or `regex`.
* A very powerful and easy to use **<abbr title="also known as components, resources, providers, services, injectables">Dependency Injection</abbr>** system.
* Security and authentication, including support for **OAuth2** with **JWT tokens** and **HTTP Basic** auth.
* More advanced (but equally easy) techniques for declaring **deeply nested JSON models** (thanks to Pydantic).

@needs_py39
def test_read_system_status(client: TestClient):
    access_token = get_access_token(client=client)
    response = client.get(
        "/status/", headers={"Authorization": f"Bearer {access_token}"}
    )
    assert response.status_code == 200, response.text
    assert response.json() == {"status": "ok"}


@needs_py39
def test_read_system_status_no_token(client: TestClient):

@needs_py310
def test_read_system_status(client: TestClient):
    access_token = get_access_token(client=client)
    response = client.get(
        "/status/", headers={"Authorization": f"Bearer {access_token}"}
    )
    assert response.status_code == 200, response.text
    assert response.json() == {"status": "ok"}


@needs_py310
def test_read_system_status_no_token(client: TestClient):

### OpenID (nicht „OpenID Connect“)

Es gab auch eine „OpenID“-Spezifikation. Sie versuchte das Gleiche zu lösen wie **OpenID Connect**, basierte aber nicht auf OAuth2.

Es handelte sich also um ein komplett zusätzliches System.

Heutzutage ist es nicht sehr populär und wird kaum verwendet.

## OpenAPI

OpenAPI (früher bekannt als Swagger) ist die offene Spezifikation zum Erstellen von APIs (jetzt Teil der Linux Foundation).

An <a href="https://en.wikipedia.org/wiki/Environment_variable" class="external-link" target="_blank">environment variable</a> (also known as "env var") is a variable that lives outside of the Python code, in the operating system, and could be read by your Python code (or by other programs as well).

You can create and use environment variables in the shell, without needing Python:

=== "Linux, macOS, Windows Bash"

    <div class="termy">

# Classes as Dependencies

Before diving deeper into the **Dependency Injection** system, let's upgrade the previous example.

## A `dict` from the previous example

In the previous example, we were returning a `dict` from our dependency ("dependable"):

=== "Python 3.10+"

    ```Python hl_lines="9"
    {!> ../../../docs_src/dependencies/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="11"

    In diesem Fall müssen Sie sich darüber keine Sorgen machen. 🤷

### Beispiele für Strategien für Vorab-Schritte

Es hängt **stark** davon ab, wie Sie **Ihr System bereitstellen**, und hängt wahrscheinlich mit der Art und Weise zusammen, wie Sie Programme starten, Neustarts durchführen, usw.

Hier sind einige mögliche Ideen:

* How to set **validation constraints** as `maximum_length` or `regex`.
* A very powerful and easy to use **<abbr title="also known as components, resources, providers, services, injectables">Dependency Injection</abbr>** system.
* Security and authentication, including support for **OAuth2** with **JWT tokens** and **HTTP Basic** auth.
* More advanced (but equally easy) techniques for declaring **deeply nested JSON models** (thanks to Pydantic).

* Wie man **Validierungseinschränkungen** wie `maximum_length` oder `regex` setzt.
* Ein sehr leistungsfähiges und einfach zu bedienendes System für **<abbr title="Dependency Injection – Einbringen von Abhängigkeiten: Auch bekannt als Komponenten, Ressourcen, Provider, Services, Injectables">Dependency Injection</abbr>**.