val partAbc = parts.nextPart()!!
    assertThat(partAbc.headers).isEqualTo(
      headersOf(
        "Content-Type",
        "text/plain; charset=utf-8",
        "Content-ID",
        "abc",
      ),
    )
    assertThat(partAbc.body.readUtf8()).isEqualTo("abcd\r\nefgh")

    val partIjk = parts.nextPart()!!
    assertThat(partIjk.headers).isEqualTo(
      headersOf(
        "Content-Type",

        method = self.METHOD

        def fetch_credentials():
            # HTTP headers are case insensitive filter out
            # all duplicate headers and pick one.
            headers = {}
            headers['content-type'] = 'application/x-www-form-urlencoded'
            headers['authorization'] = urllib3.make_headers(
                basic_auth='%s:%s' % (self.cid, self.csec))['authorization']

import com.google.common.collect.testing.testers.MapIsEmptyTester;
import com.google.common.collect.testing.testers.MapPutAllTester;
import com.google.common.collect.testing.testers.MapPutTester;
import com.google.common.collect.testing.testers.MapRemoveTester;
import com.google.common.collect.testing.testers.MapSerializationTester;
import com.google.common.collect.testing.testers.MapSizeTester;

def test_gzip_request(client: TestClient, compress):
    n = 1000
    headers = {}
    body = [1] * n
    data = json.dumps(body).encode()
    if compress:
        data = gzip.compress(data)
        headers["Content-Encoding"] = "gzip"
    headers["Content-Type"] = "application/json"
    response = client.post("/sum", content=data, headers=headers)
    assert response.json() == {"sum": n}

    val localPrincipal: Principal? = handshake.localPrincipal()
  }

  @Test @Disabled
  fun headers() {
    var headers: Headers = Headers.of("", "")
    headers = Headers.of(mapOf("" to ""))
    val size: Int = headers.size()
  }

  @Test @Disabled
  fun httpLoggingInterceptor() {
    val interceptor = HttpLoggingInterceptor()

  @SuppressWarnings("rawtypes") // class literals
  @Override
  protected List<Class<? extends AbstractTester>> getTesters() {
    List<Class<? extends AbstractTester>> testers = copyToList(super.getTesters());
    testers.addAll(ConcurrentMapTestSuiteBuilder.TESTERS);
    return testers;
  }

  @Override
  NavigableMapTestSuiteBuilder<K, V> subSuiteUsing(TestSortedMapGenerator<K, V> generator) {
    return using(generator);
  }

from fastapi import FastAPI
from fastapi.responses import JSONResponse

app = FastAPI()


@app.get("/headers/")
def get_headers():
    content = {"message": "Hello World"}
    headers = {"X-Cat-Dog": "alone in the world", "Content-Language": "en-US"}

    assert response.status_code == 401, response.text
    assert response.headers["WWW-Authenticate"] == "Basic"


def test_security_http_basic_invalid_credentials(client: TestClient):
    response = client.get(
        "/users/me", headers={"Authorization": "Basic notabase64token"}
    )
    assert response.status_code == 401, response.text
    assert response.headers["WWW-Authenticate"] == "Basic"

**FastAPI** 将从请求中接收到的 **headers** 中**提取**出**每个字段**的数据，并提供您定义的 Pydantic 模型。

## 查看文档

您可以在文档 UI 的 `/docs` 中查看所需的 headers：

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

## 禁止额外的 Headers

在某些特殊使用情况下（可能并不常见），您可能希望**限制**您想要接收的 headers。

您可以使用 Pydantic 的模型配置来禁止（ `forbid` ）任何额外（ `extra` ）字段：

def test_read_item():
    response = client.get("/items/foo", headers={"X-Token": "coneofsilence"})
    assert response.status_code == 200
    assert response.json() == {
        "id": "foo",
        "title": "Foo",
        "description": "There goes my hero",
    }


def test_read_item_bad_token():
    response = client.get("/items/foo", headers={"X-Token": "hailhydra"})
    assert response.status_code == 400