def test_post_upload_file(tmp_path):
    path = tmp_path / "test.txt"
    path.write_bytes(b"<file content>")

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


def test_openapi_schema():
    response = client.get("/openapi.json")

@needs_py39
def test_post_upload_file(tmp_path, client: TestClient):
    path = tmp_path / "test.txt"
    path.write_bytes(b"<file content>")

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


@needs_py39
def test_openapi_schema(client: TestClient):

from pathlib import Path
from typing import Optional

from fastapi import APIRouter, FastAPI, File, UploadFile
from fastapi.exceptions import HTTPException
from fastapi.testclient import TestClient

app = FastAPI()

router = APIRouter()


class ContentSizeLimitMiddleware:
    """Content size limiting middleware for ASGI applications
    Args:
      app (ASGI application): ASGI application

        if (form.uploadFile == null) {
            throwValidationError(messages -> messages.addErrorsStorageNoUploadFile(GLOBAL), () -> asListHtml(form.path));
        }
        verifyToken(() -> asListHtml(form.path));
        try {
            uploadObject(getObjectName(form.path, form.uploadFile.getFileName()), form.uploadFile);
        } catch (final StorageException e) {

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

app = FastAPI()


@app.post("/files/")
async def create_files(files: 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]}


@app.get("/")
async def main():

    assert response.status_code == 200, response.text
    assert response.json() == {"message": "No file sent"}


@needs_py310
def test_post_uploadfile_no_body(client: TestClient):
    response = client.post("/uploadfile/")
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "No upload file sent"}


@needs_py310
def test_post_file(tmp_path: Path, client: TestClient):

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

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]):

    response = client.post("/files/")
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "No file sent"}


def test_post_uploadfile_no_body():
    response = client.post("/uploadfile/")
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "No upload file sent"}


def test_post_file(tmp_path):
    path = tmp_path / "test.txt"

    assert response.status_code == 200, response.text
    assert response.json() == {"message": "No file sent"}


@needs_py310
def test_post_uploadfile_no_body(client: TestClient):
    response = client.post("/uploadfile/")
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "No upload file sent"}


@needs_py310
def test_post_file(tmp_path: Path, client: TestClient):

```

## 定义 `File` 与 `Form` 参数

创建文件和表单参数的方式与 `Body` 和 `Query` 一样：

```Python hl_lines="8"
{!../../docs_src/request_forms_and_files/tutorial001.py!}
```

文件和表单字段作为表单数据上传与接收。

声明文件可以使用 `bytes` 或 `UploadFile` 。

/// warning | "警告"

可在一个*路径操作*中声明多个 `File` 与 `Form` 参数，但不能同时声明要接收 JSON 的 `Body` 字段。因为此时请求体的编码为 `multipart/form-data`，不是 `application/json`。

这不是 **FastAPI** 的问题，而是 HTTP 协议的规定。

///

## 小结