* Ihre Abhängigkeitsfunktion („Dependable“) mit den richtigen Parametern aufzurufen.
* Sich das Ergebnis von dieser Funktion zu holen.
* Dieses Ergebnis dem Parameter Ihrer *Pfadoperation-Funktion* zuzuweisen.

```mermaid
graph TB

common_parameters(["common_parameters"])
read_items["/items/"]
read_users["/users/"]

common_parameters --> read_items
common_parameters --> read_users
```

* Получении результата из вашей функции.
* Назначении результата в параметр в вашей *функции обработки пути*.

```mermaid
graph TB

common_parameters(["common_parameters"])
read_items["/items/"]
read_users["/users/"]

common_parameters --> read_items
common_parameters --> read_users
```

Таким образом, вы пишете общий код один раз, и **FastAPI** позаботится о его вызове для ваших *операций с путями*.

    * le <abbr title="JavaScript Object Notation">JSON</abbr>.
    * <abbr title="en anglais : path parameters">les paramètres du chemin</abbr>.
    * <abbr title="en anglais : query parameters">les paramètres de la requête</abbr>.
    * les cookies.
    * <abbr title="en anglais : headers">les en-têtes</abbr>.
    * <abbr title="en anglais : forms">les formulaires</abbr>.

* <abbr title="en inglés: serialization, parsing, marshalling">Conversión</abbr> de datos de input: viniendo de la red a datos y tipos de Python. Leyendo desde:
    * JSON.
    * Path parameters.
    * Query parameters.
    * Cookies.
    * Headers.
    * Formularios.
    * Archivos.

* Anche la documentazione alternativa dell'API mostrerà il nuovo parametro della query e il _body_:

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Riepilogo

Ricapitolando, è sufficiente dichiarare **una sola volta** i tipi dei parametri, del body, ecc. come parametri di funzioni.

Questo con le annotazioni per i tipi standard di Python.

    * Eğer `None` olmasa zorunlu bir parametre olacaktı (`PUT` metodunun gövdesinde olduğu gibi).
* `PUT` isteği için `/items/{item_id}`'nin gövdesini, JSON olarak doğrulayıp okuyacak:
    * `name` adında zorunlu bir parametre olup olmadığını ve varsa tipinin `str` olup olmadığını kontol edecek.

* Mindkét _útvonal_ a `GET` műveletet használja (másik elnevezés: HTTP _metódus_).
* A `/items/{item_id}` _útvonalnak_ van egy _path paramétere_, az `item_id`, aminek `int` típusúnak kell lennie.
* A `/items/{item_id}` _útvonalnak_ még van egy opcionális, `str` típusú _query paramétere_ is, a `q`.

### Interaktív API dokumentáció

* The alternative documentation will also reflect the new query parameter and body:

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Recap

In summary, you declare **once** the types of parameters, body, etc. as function parameters.

You do that with standard modern Python types.

# Security Tools

When you need to declare dependencies with OAuth2 scopes you use `Security()`.

But you still need to define what is the dependable, the callable that you pass as a parameter to `Depends()` or `Security()`.

There are multiple tools that you can use to create those dependables, and they get integrated into OpenAPI so they are shown in the automatic docs UI, they can be used by automatically generated clients and SDKs, etc.

* Calling your dependency ("dependable") function with the correct parameters.
* Get the result from your function.
* Assign that result to the parameter in your *path operation function*.

```mermaid
graph TB

common_parameters(["common_parameters"])
read_items["/items/"]
read_users["/users/"]

common_parameters --> read_items
common_parameters --> read_users
```