from typing import Annotated, Union

from fastapi import Cookie, Depends, FastAPI

app = FastAPI()


def query_extractor(q: Union[str, None] = None):
    return q


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


@app.get("/items/")
async def read_query(

    - advanced/additional-status-codes.md
    - advanced/response-directly.md
    - advanced/custom-response.md
    - advanced/additional-responses.md
    - advanced/response-cookies.md
    - advanced/response-headers.md
    - advanced/response-change-status-code.md
    - advanced/advanced-dependencies.md
    - Advanced Security:
      - advanced/security/index.md

* HTTP 基本认证。
* **OAuth2** (也使用 **JWT tokens**)。在 [OAuth2 with JWT](tutorial/security/oauth2-jwt.md){.internal-link target=_blank}查看教程。
* API 密钥，在:
    * 请求头。
    * 查询参数。
    * Cookies, 等等。

加上来自 Starlette（包括 **session cookie**）的所有安全特性。

所有的这些都是可复用的工具和组件，可以轻松与你的系统，数据仓库，关系型以及 NoSQL 数据库等等集成。



### 依赖注入

# `Response` class

You can declare a parameter in a *path operation function* or dependency to be of type `Response` and then you can set data for the response like headers or cookies.

You can also use it directly to create an instance of it and return it from your *path operations*.

You can import it directly from `fastapi`:

```python
from fastapi import Response
```

    authorizationResponse:
      allowedClientHeaders:
        patterns:
        - exact: Set-cookie
          ignoreCase: true
        - ignoreCase: true
          prefix: x-prefix-
        - ignoreCase: true
          suffix: -suffix
      allowedClientHeadersOnSuccess:
        patterns:
        - exact: Set-cookie
          ignoreCase: true
        - ignoreCase: true
          prefix: x-prefix-

# `Response`-Klasse

Sie können einen Parameter in einer *Pfadoperation-Funktion* oder einer Abhängigkeit als `Response` deklarieren und dann Daten für die Response wie Header oder Cookies festlegen.

Diese können Sie auch direkt verwenden, um eine Instanz davon zu erstellen und diese von Ihren *Pfadoperationen* zurückzugeben.

Sie können sie direkt von `fastapi` importieren:

```python
from fastapi import Response
```

    from typing import Annotated

    from fastapi import (
        Cookie,
        FastAPI,
        WebSocket,
        WebSocketException,
        status,
    )

    app = FastAPI()

    @app.websocket("/items/{item_id}/ws")
    async def websocket_endpoint(
        *,
        websocket: WebSocket,
        session: Annotated[str | None, Cookie()] = None,
        item_id: str,
    ):
        if session is None:

pkg net, type ListenConfig struct, KeepAliveConfig KeepAliveConfig #62254
pkg net/http, func ParseCookie(string) ([]*Cookie, error) #66008
pkg net/http, func ParseSetCookie(string) (*Cookie, error) #66008
pkg net/http, method (*Request) CookiesNamed(string) []*Cookie #61472
pkg net/http, type Cookie struct, Partitioned bool #62490
pkg net/http, type Cookie struct, Quoted bool #46443
pkg net/http, type Request struct, Pattern string #66405

//go:linkname badRoundTrip net/http.(*Transport).RoundTrip
func badRoundTrip(*Transport, *Request) (*Response, error)

// RoundTrip implements the [RoundTripper] interface.
//
// For higher-level HTTP client support (such as handling of cookies
// and redirects), see [Get], [Post], and the [Client] type.
//
// Like the RoundTripper interface, the error types returned
// by RoundTrip are unspecified.
func (t *Transport) RoundTrip(req *Request) (*Response, error) {

// We treat this like an ordinary system call rather than a call
// that tries to fill the buffer.
func (fd *FD) ReadDir(buf []byte, cookie syscall.Dircookie) (int, error) {
	if err := fd.incref(); err != nil {
		return 0, err
	}
	defer fd.decref()
	for {
		n, err := syscall.ReadDir(fd.Sysfd, buf, cookie)
		if err != nil {
			n = 0
			if err == syscall.EAGAIN && fd.pd.pollable() {