But still, FastAPI got quite some inspiration from Requests.

**Requests** is a library to *interact* with APIs (as a client), while **FastAPI** is a library to *build* APIs (as a server).

They are, more or less, at opposite ends, complementing each other.

Requests has a very simple and intuitive design, it's very easy to use, with sensible defaults. But at the same time, it's very powerful and customizable.

That's why, as said in the official website:

    start_datetime: datetime = Body(),
    end_datetime: datetime = Body(),
    process_after: timedelta = Body(),
    repeat_at: Union[time, None] = Body(default=None),
):
    start_process = start_datetime + process_after
    duration = end_datetime - start_process
    return {
        "item_id": item_id,
        "start_datetime": start_datetime,
        "end_datetime": end_datetime,
        "process_after": process_after,

                            "type": "string",
                            "format": "date-time",
                        },
                        "end_datetime": {
                            "title": "End Datetime",
                            "type": "string",
                            "format": "date-time",
                        },
                        "repeat_at": IsDict(

    opt Tasks
        operation -->> tasks: Send background tasks
    end
    opt Raise other exception
        tasks -->> dep: Raise other exception
    end
    Note over dep: After yield
    opt Handle other exception
        dep -->> dep: Handle exception, can't change response. E.g. close DB session.
    end
```

!!! info
    🕴 **1️⃣ 📨** 🔜 📨 👩‍💻. ⚫️ 💪 1️⃣ ❌ 📨 ⚖️ ⚫️ 🔜 📨 ⚪️➡️ *➡ 🛠️*.

        execute ->> code: return the result
    end

    rect rgba(0, 255, 255, .1)
        code ->> function: say_hi(name="Camila")
        function ->> code: return stored result
    end

    rect rgba(0, 255, 0, .1)
        code ->> function: say_hi(name="Rick")
        function ->> execute: execute function code
        execute ->> code: return the result
    end

    rect rgba(0, 255, 0, .1)

So, let's review it from that simplified point of view:

* The user types the `username` and `password` in the frontend, and hits `Enter`.
* The frontend (running in the user's browser) sends that `username` and `password` to a specific URL in our API (declared with `tokenUrl="token"`).
* The API checks that `username` and `password`, and responds with a "token" (we haven't implemented any of this yet).

Sie übergeben `Depends` nur einen einzigen Parameter.

Dieser Parameter muss so etwas wie eine Funktion sein.

Sie **rufen diese nicht direkt auf** (fügen Sie am Ende keine Klammern hinzu), sondern übergeben sie einfach als Parameter an `Depends()`.

Und diese Funktion akzeptiert Parameter auf die gleiche Weise wie *Pfadoperation-Funktionen*.

!!! tip "Tipp"

Sie wird direkt in FastAPI importiert/inkludiert, sodass Sie sie von `fastapi` importieren können und vermeiden, versehentlich das alternative `BackgroundTask` (ohne das `s` am Ende) von `starlette.background` zu importieren.

<img src="/img/tutorial/path-operation-configuration/image01.png">

### Tags mittels Enumeration

Wenn Sie eine große Anwendung haben, können sich am Ende **viele Tags** anhäufen, und Sie möchten sicherstellen, dass Sie für verwandte *Pfadoperationen* immer den **gleichen Tag** nehmen.

In diesem Fall macht es Sinn, die Tags in einem `Enum` zu speichern.

### HTTPS Request

Now that the client and server (specifically the browser and the TLS Termination Proxy) have an **encrypted TCP connection**, they can start the **HTTP communication**.

So, the client sends an **HTTPS request**. This is just an HTTP request through an encrypted TLS connection.

<img src="/img/deployment/https/https04.svg">

### Decrypt the Request