from fastapi import FastAPI, File, UploadFile

app = FastAPI()


@app.post("/files/")
async def create_file(file: Union[bytes, None] = File(default=None)):
    if not file:
        return {"message": "No file sent"}
    else:
        return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(file: Union[UploadFile, None] = None):
    if not file:

def query_or_cookie_extractor(
    q: str = Depends(query_extractor), last_query: str | None = Cookie(default=None)
):
    if not q:
        return last_query
    return q


@app.get("/items/")
async def read_query(query_or_default: str = Depends(query_or_cookie_extractor)):

class CommonHeaders(BaseModel):
    host: str
    save_data: bool
    if_modified_since: Union[str, None] = None
    traceparent: Union[str, None] = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: Annotated[CommonHeaders, Header()]):

```Python
with open("file.txt") as file:
    file.read()
```

В последних версиях Python есть также асинхронный менеджер контекста. Его используют с `async with`:

```Python
async with lifespan(app):
    await do_stuff()
```

    description: str | None = None
    price: float
    tax: float | None = None
    tags: list[str] = []


@app.post("/items/", response_model=Item)
async def create_item(item: Item) -> Any:
    return item


@app.get("/items/", response_model=list[Item])
async def read_items() -> Any:
    return [
        {"name": "Portal Gun", "price": 42.0},
        {"name": "Plumbus", "price": 32.0},

@app.exception_handler(RequestValidationError)
async def validation_exception_handler(request: Request, exc: RequestValidationError):
    return JSONResponse(
        status_code=422,
        content=jsonable_encoder({"detail": exc.errors(), "body": exc.body}),
    )


class Item(BaseModel):
    title: str
    size: int


@app.post("/items/")
async def create_item(item: Item):

	"context"
	"errors"
	"fmt"
	"io"
	"math/rand"
	"net/http"
	"net/url"
	"runtime"
	"sync"
	"time"

	"github.com/cespare/xxhash/v2"
	"github.com/klauspost/compress/zip"
	"github.com/minio/madmin-go/v3"
	xioutil "github.com/minio/minio/internal/ioutil"
	xnet "github.com/minio/pkg/v3/net"
	"github.com/minio/pkg/v3/sync/errgroup"
	"github.com/minio/pkg/v3/workers"

	"github.com/minio/minio/internal/bucket/bandwidth"

//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"sync"

	"github.com/dustin/go-humanize"
)

const (
	// Block size used for all internal operations version 1.

	// TLDR..
	// Not used anymore xl.meta captures the right blockSize

class Product(BaseModel):
    name: str
    price: float


class Shop(BaseModel):
    name: str


@app.post("/products")
async def create_product(data: Product = Body(media_type=media_type, embed=True)):
    pass  # pragma: no cover


@app.post("/shops")
async def create_shop(
    data: Shop = Body(media_type=media_type),
    included: list[Product] = Body(default=[], media_type=media_type),
):

    q: Annotated[str, Depends(query_extractor)],
    last_query: Annotated[str | None, Cookie()] = None,
):
    if not q:
        return last_query
    return q


@app.get("/items/")
async def read_query(
    query_or_default: Annotated[str, Depends(query_or_cookie_extractor)],
):