# `UploadFile` class

You can define *path operation function* parameters to be of the type `UploadFile` to receive files from the request.

You can import it directly from `fastapi`:

```python
from fastapi import UploadFile
```

::: fastapi.UploadFile
    options:
        members:
            - file
            - filename
            - size
            - headers
            - content_type
            - read

from typing import Annotated

from fastapi import FastAPI, File, UploadFile

app = FastAPI()


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


@app.post("/uploadfile/")
async def create_upload_file(file: UploadFile):

from typing import Annotated

from fastapi import FastAPI, File, UploadFile
from fastapi.responses import HTMLResponse

app = FastAPI()


@app.post("/files/")
async def create_files(files: Annotated[list[bytes], File()]):
    return {"file_sizes": [len(file) for file in files]}


@app.post("/uploadfiles/")
async def create_upload_files(files: list[UploadFile]):
    return {"filenames": [file.filename for file in files]}

Aber es gibt viele Fälle, in denen Sie davon profitieren, `UploadFile` zu verwenden.

## Datei-Parameter mit `UploadFile` { #file-parameters-with-uploadfile }

Definieren Sie einen Datei-Parameter mit dem Typ `UploadFile`:

{* ../../docs_src/request_files/tutorial001_an_py39.py hl[14] *}

`UploadFile` zu verwenden, hat mehrere Vorzüge gegenüber `bytes`:

    return {"file_size": len(p) if p else None}


@app.post("/optional-uploadfile", operation_id="optional_uploadfile")
async def read_optional_uploadfile(p: Annotated[Optional[UploadFile], File()] = None):
    return {"file_size": p.size if p else None}


@pytest.mark.parametrize(
    "path",
    [
        "/optional-bytes",
        "/optional-uploadfile",
    ],
)
def test_optional_schema(path: str):

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")],
):

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_py39.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_py39.py hl[14] *}

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

Pero hay varios casos en los que podrías beneficiarte de usar `UploadFile`.

## Parámetros de Archivo con `UploadFile` { #file-parameters-with-uploadfile }

Define un parámetro de archivo con un tipo de `UploadFile`:

{* ../../docs_src/request_files/tutorial001_an_py39.py hl[14] *}

Usar `UploadFile` tiene varias ventajas sobre `bytes`:

///

文件作为「表单数据」上传。

如果把*路径操作函数*参数的类型声明为 `bytes`，**FastAPI** 将以 `bytes` 形式读取和接收文件内容。

这种方式把文件的所有内容都存储在内存里，适用于小型文件。

不过，很多情况下，`UploadFile` 更好用。

## 含 `UploadFile` 的文件参数

定义文件参数时使用 `UploadFile`：

{* ../../docs_src/request_files/tutorial001.py hl[12] *}

`UploadFile` 与 `bytes` 相比有更多优势：

* 使用 `spooled` 文件：
    * 存储在内存的文件超出最大上限时，FastAPI 会把文件存入磁盘；
* 这种方式更适于处理图像、视频、二进制文件等大型文件，好处是不会占用所有内存；
* 可获取上传文件的元数据；