* **TCP weiß nichts über „<abbr title="Domäne, Bereich, Wirkungsraum">Domains</abbr>“**. Nur über IP-Adressen.
    * Die Informationen über die angeforderte **spezifische Domain** befinden sich in den **HTTP-Daten**.
* Die **HTTPS-Zertifikate** „zertifizieren“ eine **bestimmte Domain**, aber das Protokoll und die Verschlüsselung erfolgen auf TCP-Ebene, **ohne zu wissen**, um welche Domain es sich handelt.

```Python hl_lines="2  6-8"
{!../../../docs_src/advanced_middleware/tutorial002.py!}
```

The following arguments are supported:

* `allowed_hosts` - A list of domain names that should be allowed as hostnames. Wildcard domains such as `*.example.com` are supported for matching subdomains. To allow any hostname either use `allowed_hosts=["*"]` or omit the middleware.

* **Flower** für die Überwachung von Celery-Jobs.
* Load Balancing zwischen Frontend und Backend mit **Traefik**, sodass Sie beide unter derselben Domain haben können, getrennt durch den Pfad, aber von unterschiedlichen Containern ausgeliefert.
* Traefik-Integration, einschließlich automatischer Generierung von Let's Encrypt-**HTTPS**-Zertifikaten.

* **TCP doesn't know about "domains"**. Only about IP addresses.
    * The information about the **specific domain** requested goes in the **HTTP data**.
* The **HTTPS certificates** "certify" a **certain domain**, but the protocol and encryption happen at the TCP level, **before knowing** which domain is being dealt with.

## Origin

An origin is the combination of protocol (`http`, `https`), domain (`myapp.com`, `localhost`, `localhost.tiangolo.com`), and port (`80`, `443`, `8080`).

So, all these are different origins:

* `http://localhost`
* `https://localhost`
* `http://localhost:8080`

* **PGAdmin** PostgreSQL database admin tool'u, PHPMyAdmin ve MySQL ile kolayca değiştirilebilir.
* **Flower** ile Celery job'larını monitörleme.
* **Traefik** ile backend ve frontend arasında yük dengeleme, böylece her ikisini de aynı domain altında, path ile ayrılmış, ancak farklı kapsayıcılar tarafından sunulabilirsiniz.
* Let's Encrypt **HTTPS** sertifikalarının otomatik oluşturulması dahil olmak üzere Traefik entegrasyonu.

}

app = FastAPI()


class Item(BaseModel):
    id: str
    title: str
    description: Union[str, None] = None


@app.get("/items/{item_id}", response_model=Item)
async def read_main(item_id: str, x_token: str = Header()):
    if x_token != fake_secret_token:
        raise HTTPException(status_code=400, detail="Invalid X-Token header")
    if item_id not in fake_db:

Sebastián Ramírez <******@****.***> 1606671138 +0100

Sebastián Ramírez <******@****.***> 1698179166 +0400

from fastapi.testclient import TestClient

from .main import app

client = TestClient(app)


def test_read_item():
    response = client.get("/items/foo", headers={"X-Token": "coneofsilence"})
    assert response.status_code == 200
    assert response.json() == {
        "id": "foo",
        "title": "Foo",
        "description": "There goes my hero",
    }


def test_read_item_bad_token():