This is not a limitation of **FastAPI**, it's part of the HTTP protocol.

///

## Optional File Upload

You can make a file optional by using standard type annotations and setting a default value of `None`:

//// tab | Python 3.10+

```Python hl_lines="9  17"
{!> ../../docs_src/request_files/tutorial001_02_an_py310.py!}
```

////

   * </ul>
   *
   * <p>This escaper is suitable for escaping parameter names and values even when <a
   * href="https://www.w3.org/TR/html401/appendix/notes.html#h-B.2.2">using the non-standard
   * semicolon</a>, rather than the ampersand, as a parameter delimiter. Nevertheless, we recommend
   * using the ampersand unless you must interoperate with systems that require semicolons.
   *

# FastAPI CLI

**FastAPI CLI**는 FastAPI 애플리케이션을 실행하고, 프로젝트를 관리하는 등 다양한 작업을 수행할 수 있는 커맨드 라인 프로그램입니다.

FastAPI를 설치할 때 (예: `pip install "fastapi[standard]"` 명령어를 사용할 경우), `fastapi-cli`라는 패키지가 포함됩니다. 이 패키지는 터미널에서 사용할 수 있는 `fastapi` 명령어를 제공합니다.

개발용으로 FastAPI 애플리케이션을 실행하려면 다음과 같이 `fastapi dev` 명령어를 사용할 수 있습니다:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:single">main.py</u>

 * implement subtleties of the API improperly.
 *
 * <p><b>Custom implementation</b>: Avoid implementing {@code ListenableFuture} from scratch. If you
 * can't get by with the standard implementations, prefer to derive a new {@code Future} instance
 * with the methods in {@link Futures} or, if necessary, to extend {@link AbstractFuture}.
 *

    case $link in             #(
      /*)   app_path=$link ;; #(
      *)    app_path=$APP_HOME$link ;;
    esac
done

# This is normally unused
# shellcheck disable=SC2034
APP_BASE_NAME=${0##*/}
# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit

# Use the maximum available, or set MAX_FD != -1 to use that value.
MAX_FD=maximum

 * implement subtleties of the API improperly.
 *
 * <p><b>Custom implementation</b>: Avoid implementing {@code ListenableFuture} from scratch. If you
 * can't get by with the standard implementations, prefer to derive a new {@code Future} instance
 * with the methods in {@link Futures} or, if necessary, to extend {@link AbstractFuture}.
 *

```Python hl_lines="4"
{!> ../../docs_src/body/tutorial001.py!}
```

////

## Erstellen Sie Ihr Datenmodell

Dann deklarieren Sie Ihr Datenmodell als eine Klasse, die von `BaseModel` erbt.

Verwenden Sie Standard-Python-Typen für die Klassenattribute:

//// tab | Python 3.10+

```Python hl_lines="5-9"
{!> ../../docs_src/body/tutorial001_py310.py!}
```

////

//// tab | Python 3.8+

<div class="termy">

```console
$ pip install "fastapi[standard]"

---> 100%
```

</div>

👆 🔜 💪 🔫 💽, 🏭 ✅ <a href="https://www.uvicorn.org" class="external-link" target="_blank">Uvicorn</a> ⚖️ <a href="https://github.com/pgjones/hypercorn" class="external-link" target="_blank">Hypercorn</a>.

<div class="termy">

```console
$ pip install "uvicorn[standard]"

---> 100%
```

</div>

Todo está basado en las declaraciones de tipo de **Python 3.8** estándar (gracias a Pydantic). No necesitas aprender una sintaxis nueva, solo Python moderno.

Si necesitas un repaso de 2 minutos de cómo usar los tipos de Python (así no uses FastAPI) prueba el tutorial corto: [Python Types](python-types.md){.internal-link target=_blank}.

Escribes Python estándar con tipos así:

```Python
from datetime import date

	if forceStr := r.Form.Get("force"); forceStr != "" {
		ignoreInUse, _ = strconv.ParseBool(forceStr)
	}

	// Disallow remote tiers with internal storage class names
	switch cfg.Name {
	case storageclass.STANDARD, storageclass.RRS:
		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, errTierReservedName), r.URL)
		return
	}

	// Refresh from the disk in case we had missed notifications about edits from peers.