from fastapi import FastAPI, Header
from pydantic import BaseModel

app = FastAPI()


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


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

                "loc": ["header", "p"],
                "msg": "Field required",
                "input": AnyThing,
            }
        ]
    }


@pytest.mark.parametrize(
    "path",
    ["/required-list-str", "/model-required-list-str"],
)
def test_required_list_str(path: str):
    client = TestClient(app)
    response = client.get(path, headers=[("p", "hello"), ("p", "world")])

from fastapi import FastAPI, Header
from pydantic import BaseModel

app = FastAPI()


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: CommonHeaders = Header()):

 */
interface TrailersSource {
  @Throws(IOException::class)
  fun peek(): Headers? = null

  @Throws(IOException::class)
  fun get(): Headers

  companion object {
    @JvmField
    val EMPTY: TrailersSource =
      object : TrailersSource {
        override fun peek() = Headers.EMPTY

        override fun get() = Headers.EMPTY
      }
  }

Você pode ver os headers necessários na interface gráfica da documentação em `/docs`:

<div class="screenshot">
<img src="/img/tutorial/header-param-models/image01.png">
</div>

## Proibindo Cabeçalhos adicionais { #forbid-extra-headers }

Em alguns casos de uso especiais (provavelmente não muito comuns), você pode querer **restringir** os cabeçalhos que você quer receber.

    get() {
      val result = mutableListOf<Header>()
      for (inputHeader in headers) {
        val (key, value) = inputHeader.entries.iterator().next()
        result.add(Header(key, value))
      }
      return result
    }

  public override fun clone() = Case(seqno, this.wire, headers)

	if proto := r.Header.Get(xForwardedProto); proto != "" {
		scheme = strings.ToLower(proto)
	} else if proto = r.Header.Get(xForwardedScheme); proto != "" {
		scheme = strings.ToLower(proto)
	} else if proto := r.Header.Get(forwarded); proto != "" {
		// match should contain at least two elements if the protocol was
		// specified in the Forwarded header. The first element will always be

		return map[string]string{}
	}
	return map[string]string{
		"requestId":      w.Header().Get(xhttp.AmzRequestID),
		"nodeId":         w.Header().Get(xhttp.AmzRequestHostID),
		"content-length": w.Header().Get(xhttp.ContentLength),
		// Add more fields here.
	}
}

// Trims away `aws-chunked` from the content-encoding header if present.
// Streaming signature clients can have custom content-encoding such as

    }

  fun assertHeader(
    name: String,
    vararg values: String?,
  ) = apply {
    assertThat(response!!.headers(name)).containsExactly(*values)
  }

  fun assertHeaders(headers: Headers) =
    apply {
      assertThat(response!!.headers).isEqualTo(headers)
    }

  fun assertBody(expectedBody: String) =
    apply {
      assertThat(body).isEqualTo(expectedBody)
    }

    return client


@pytest.mark.parametrize(
    "path,headers,expected_status,expected_response",
    [
        ("/items", None, 200, {"User-Agent": "testclient"}),
        ("/items", {"X-Header": "notvalid"}, 200, {"User-Agent": "testclient"}),
        ("/items", {"User-Agent": "FastAPI test"}, 200, {"User-Agent": "FastAPI test"}),
    ],
)
def test(path, headers, expected_status, expected_response, client: TestClient):