But there are several cases in which you might benefit from using `UploadFile`.

## File Parameters with `UploadFile` { #file-parameters-with-uploadfile }

Define a file parameter with a type of `UploadFile`:

{* ../../docs_src/request_files/tutorial001_an_py310.py hl[14] *}

Using `UploadFile` has several advantages over `bytes`:

* You don't have to use `File()` in the default value of the parameter.

Mas há muitos casos em que você pode se beneficiar do uso de `UploadFile`.

## Parâmetros de Arquivo com `UploadFile` { #file-parameters-with-uploadfile }

Defina um parâmetro de arquivo com um tipo de `UploadFile`:

{* ../../docs_src/request_files/tutorial001_an_py310.py hl[14] *}

Utilizar `UploadFile` tem várias vantagens sobre `bytes`:

如果你將路徑操作函式（path operation function）的參數型別宣告為 `bytes`，**FastAPI** 會替你讀取檔案，你會以 `bytes` 取得內容。

請注意，這表示整個內容會存放在記憶體中，適合小檔案。

但在許多情況下，使用 `UploadFile` 會更好。

## 使用 `UploadFile` 的檔案參數 { #file-parameters-with-uploadfile }

將檔案參數型別設為 `UploadFile`：

{* ../../docs_src/request_files/tutorial001_an_py310.py hl[14] *}

使用 `UploadFile` 相較於 `bytes` 有數個優點：

* 你不必在參數的預設值使用 `File()`。
* 它使用「spooled」檔案：
    * 檔案在記憶體中保存到某個大小上限，超過上限後會存到磁碟。

    app = FastAPI()

    testing_file_store: list[UploadFile] = []

    @app.post("/uploadfile/")
    def create_upload_file(file: UploadFile):
        testing_file_store.append(file)
        return {"filename": file.filename}

    client = TestClient(app)
    with path.open("rb") as file:
        response = client.post("/uploadfile/", files={"file": file})
    assert response.status_code == 200, response.text

Ancak bazı durumlarda `UploadFile` kullanmak size fayda sağlayabilir.

## `UploadFile` ile Dosya Parametreleri { #file-parameters-with-uploadfile }

Tipi `UploadFile` olan bir dosya parametresi tanımlayın:

{* ../../docs_src/request_files/tutorial001_an_py310.py hl[14] *}

`UploadFile` kullanmanın `bytes`’a göre birkaç avantajı vardır:

from typing import Annotated

from fastapi import FastAPI, File, UploadFile

app = FastAPI()


@app.post("/files/")
async def create_file(file: Annotated[bytes, File(description="A file read as bytes")]):
    return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(
    file: Annotated[UploadFile, File(description="A file read as UploadFile")],
):

def is_uploadfile_or_nonable_uploadfile_annotation(annotation: Any) -> bool:
    if lenient_issubclass(annotation, UploadFile):
        return True
    origin = get_origin(annotation)
    if origin is Union or origin is UnionType:
        for arg in get_args(annotation):
            if lenient_issubclass(arg, UploadFile):
                return True
    return False


def is_bytes_sequence_annotation(annotation: Any) -> bool:

Однако возможны случаи, когда использование `UploadFile` может оказаться полезным.

## Параметры файла с `UploadFile` { #file-parameters-with-uploadfile }

Определите параметр файла с типом `UploadFile`:

{* ../../docs_src/request_files/tutorial001_an_py310.py hl[14] *}

Использование `UploadFile` имеет ряд преимуществ перед `bytes`:

__version__ = "0.135.3"

from starlette import status as status

from .applications import FastAPI as FastAPI
from .background import BackgroundTasks as BackgroundTasks
from .datastructures import UploadFile as UploadFile
from .exceptions import HTTPException as HTTPException
from .exceptions import WebSocketException as WebSocketException
from .param_functions import Body as Body
from .param_functions import Cookie as Cookie

이것은 전체 내용이 메모리에 저장된다는 것을 의미한다는 걸 염두하기 바랍니다. 이는 작은 크기의 파일들에 적합합니다.

어떤 경우에는 `UploadFile` 을 사용하는 것이 더 유리합니다.

## `UploadFile`을 사용하는 `File` 매개변수 { #file-parameters-with-uploadfile }

`File` 매개변수를 `UploadFile` 타입으로 정의합니다:

{* ../../docs_src/request_files/tutorial001_an_py310.py hl[14] *}

`UploadFile` 을 사용하는 것은 `bytes` 과 비교해 다음과 같은 장점이 있습니다:

* 매개변수의 기본값에서 `File()`을 사용할 필요가 없습니다.
* "스풀 파일"을 사용합니다.