& 👥 💪 🚮 📇 `dependencies` 👈 🔜 🚮 🌐 *➡ 🛠️* 📻 & 🔜 🛠️/❎ 🔠 📨 ⚒ 👫.

/// tip

🗒 👈, 🌅 💖 [🔗 *➡ 🛠️ 👨‍🎨*](dependencies/dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, 🙅‍♂ 💲 🔜 🚶‍♀️ 👆 *➡ 🛠️ 🔢*.

///

🔚 🏁 👈 🏬 ➡ 🔜:

* `/items/`
* `/items/{item_id}`

...👥 🎯.

* 👫 🔜 ™ ⏮️ 📇 🔖 👈 🔌 👁 🎻 `"items"`.

would be valid to use as a **FastAPI** dependency.

In fact, FastAPI uses those two decorators internally.

///

## A database dependency with `yield` { #a-database-dependency-with-yield }

For example, you could use this to create a database session and close it after finishing.

/// tip | Consejo

Nota que, al igual que [dependencias en decoradores de *path operations*](dependencies/dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, ningún valor será pasado a tu *path operation function*.

///

El resultado final es que los paths de item son ahora:

* `/items/`

/// tip | Dica

Observe que, assim como [dependências em *decoradores de operação de rota*](dependencies/dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, nenhum valor será passado para sua *função de operação de rota*.

///

O resultado final é que os caminhos dos itens agora são:

## Additional Response with `model` { #additional-response-with-model }

You can pass to your *path operation decorators* a parameter `responses`.

It receives a `dict`: the keys are status codes for each response (like `200`), and the values are other `dict`s with the information for each of them.

You put it on top of a function. Like a pretty decorative hat (I guess that's where the term came from).

A "decorator" takes the function below and does something with it.

In our case, this decorator tells **FastAPI** that the function below corresponds to the **path** `/` with an **operation** `get`.

It is the "**path operation decorator**".

///

You can also use the other operations:

* `@app.post()`

    * Zuerst werden die Router-Abhängigkeiten ausgeführt, dann die [`dependencies` im Dekorator](dependencies/dependencies-in-path-operation-decorators.md){.internal-link target=_blank} und dann die normalen Parameterabhängigkeiten.

      - tutorial/dependencies/index.md
      - tutorial/dependencies/classes-as-dependencies.md
      - tutorial/dependencies/sub-dependencies.md
      - tutorial/dependencies/dependencies-in-path-operation-decorators.md
      - tutorial/dependencies/global-dependencies.md
      - tutorial/dependencies/dependencies-with-yield.md
    - Security:
      - tutorial/security/index.md
      - tutorial/security/first-steps.md

## `Security` en `dependencies` del decorador

compilation to JavaScript, it cannot rely on the types to define validation, serialization and documentation at the same time. Due to this and some design decisions, to get validation, serialization and automatic schema generation, it's needed to add decorators in many places. So, it becomes quite verbose.

It can't handle nested models very well. So, if the JSON body in the request is a JSON object that has inner fields that in turn are nested JSON objects, it cannot be properly documented and...