{"item_id":3}
```

/// check | Testen

Beachten Sie, dass der Wert, den Ihre Funktion erhält und zurückgibt, die Zahl `3` ist, also ein `int`. Nicht der String `"3"`, also ein `str`.

Sprich, mit dieser Typdeklaration wird **FastAPI** den <abbr title="Request – Anfrage: Daten, die der Client zum Server sendet">Request</abbr> automatisch <abbr title="Den String, der von einem HTTP-Request kommt, in Python-Objekte konvertieren">„parsen“</abbr>.

///

from typing import Annotated, Union

from fastapi import Depends, FastAPI, HTTPException, Query
from sqlmodel import Field, Session, SQLModel, create_engine, select


class HeroBase(SQLModel):
    name: str = Field(index=True)
    age: Union[int, None] = Field(default=None, index=True)


class Hero(HeroBase, table=True):
    id: Union[int, None] = Field(default=None, primary_key=True)
    secret_name: str


class HeroPublic(HeroBase):

import importlib

import pytest
from fastapi.testclient import TestClient

from ...utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial005_py39"),
        pytest.param("tutorial005_py310", marks=needs_py310),
        pytest.param("tutorial005_an_py39"),
        pytest.param("tutorial005_an_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):

/// info

- 除非在 `responses` 参数中明确指定不同的媒体类型，否则**FastAPI**将假定响应与主响应类具有相同的媒体类型（默认为` application/json` ）。
- 但是如果您指定了一个自定义响应类，并将 `None `作为其媒体类型，**FastAPI**将使用 `application/json` 作为具有关联模型的任何其他响应。

///

## 组合信息
您还可以联合接收来自多个位置的响应信息，包括 `response_model `、 `status_code` 和 `responses `参数。

您可以使用默认的状态码 `200` （或者您需要的自定义状态码）声明一个 `response_model `，然后直接在OpenAPI模式中在 `responses` 中声明相同响应的其他信息。

**FastAPI**将保留来自 `responses` 的附加信息，并将其与模型中的JSON Schema结合起来。

/// note | Nota

FastAPI sabrá que el valor de `q` no es requerido debido al valor por defecto `= None`.

El `str | None` (Python 3.10+) o `Union` en `Union[str, None]` (Python 3.9+) no es utilizado por FastAPI para determinar que el valor no es requerido, sabrá que no es requerido porque tiene un valor por defecto de `= None`.

///

## Type hints no **FastAPI** { #type-hints-in-fastapi }

O **FastAPI** aproveita esses type hints para fazer várias coisas.

Com o **FastAPI**, você declara parâmetros com type hints e obtém:

* **Suporte ao editor**.
* **Verificações de tipo**.

... e o **FastAPI** usa as mesmas declarações para:

///

## Anotaciones de tipos en **FastAPI** { #type-hints-in-fastapi }

**FastAPI** aprovecha estas anotaciones de tipos para hacer varias cosas.

Con **FastAPI** declaras parámetros con anotaciones de tipos y obtienes:

* **Soporte del editor**.
* **Chequeo de tipos**.

...y **FastAPI** usa las mismas declaraciones para:

# External Links

**FastAPI** has a great community constantly growing.

There are many posts, articles, tools, and projects, related to **FastAPI**.

You could easily use a search engine or video platform to find many resources related to FastAPI.

/// info

Before, this page used to list links to external articles.

# Sub Applications - Mounts { #sub-applications-mounts }

If you need to have two independent FastAPI applications, with their own independent OpenAPI and their own docs UIs, you can have a main app and "mount" one (or more) sub-application(s).

## Mounting a **FastAPI** application { #mounting-a-fastapi-application }

You can use the `Jinja2Templates` class to render Jinja templates.

Read more about it in the [FastAPI docs for Templates](https://fastapi.tiangolo.com/advanced/templates/).

You can import it directly from `fastapi.templating`:

```python
from fastapi.templating import Jinja2Templates
```