app = FastAPI()

api_key = APIKeyCookie(name="key", auto_error=False)


class User(BaseModel):
    username: str


def get_current_user(oauth_header: Optional[str] = Security(api_key)):
    if oauth_header is None:
        return None
    user = User(username=oauth_header)
    return user


@app.get("/users/me")
def read_current_user(current_user: User = Depends(get_current_user)):
    if current_user is None:

          url = "https://url-host.com:${server.port}/".toHttpUrl(),
          headers = headersOf("Host", "header-host"),
        ),
      )
    val response = call.execute()
    assertThat(response.isSuccessful).isTrue()

    val recordedRequest = server.takeRequest()
    assertThat(recordedRequest.requestUrl!!.host).isEqualTo("header-host")
    assertThat(recordedRequest.handshakeServerNames).containsExactly("url-host.com")

{!../../../docs_src/middleware/tutorial001.py!}
```

!!! tip "Tipp"
    Beachten Sie, dass benutzerdefinierte proprietäre Header hinzugefügt werden können. <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">Verwenden Sie dafür das Präfix 'X-'</a>.

from typing_extensions import Annotated


async def verify_token(x_token: Annotated[str, Header()]):
    if x_token != "fake-super-secret-token":
        raise HTTPException(status_code=400, detail="X-Token header invalid")


async def verify_key(x_key: Annotated[str, Header()]):
    if x_key != "fake-super-secret-key":
        raise HTTPException(status_code=400, detail="X-Key header invalid")

        verifyTokenKeep(() -> asListHtml(this::saveToken));

        String header = null;
        final StringBuilder buf = new StringBuilder(1000);
        try (final BufferedReader reader = new BufferedReader(new InputStreamReader(form.requestFile.getInputStream(), Constants.UTF_8))) {
            header = ReaderUtil.readLine(reader);
            if (header == null) {

    assertThat(request.header("Referer")).isEqualTo("foo")
    assertThat(request.body).isNull()
  }

  @Test
  fun userAgent() {
    val request = fromArgs("-A", "foo", "http://example.com").createRequest()
    assertThat(request.method).isEqualTo("GET")
    assertThat(request.url.toString()).isEqualTo("http://example.com/")
    assertThat(request.header("User-Agent")).isEqualTo("foo")

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(x_token: list[str] | None = Header(default=None)):

from typing import Annotated

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(user_agent: Annotated[str | None, Header()] = None):

from typing import Annotated, Union

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(user_agent: Annotated[Union[str, None], Header()] = None):

	"runtime"
	"sync"

	"github.com/bcicen/jstream"
	"github.com/minio/minio/internal/s3select/sql"
)

// PReader - JSON record reader for S3Select.
// Operates concurrently on line-delimited JSON.
type PReader struct {
	args        *ReaderArgs
	readCloser  io.ReadCloser   // raw input
	buf         *bufio.Reader   // input to the splitter
	current     []jstream.KVS   // current block of results to be returned