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"}

        Map<String, List<String>> headers = new HashMap<>();
        headers.put("Content-Type", Arrays.asList("application/json"));
        headers.put("Content-Length", Arrays.asList("100"));

        response.setHeaders(headers);

        Map<String, List<String>> result = response.getHeaders();
        assertNotNull(result);
        // Headers should be stored in lowercase

**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：

 * limitations under the License.
 */
package okhttp3.mockwebserver

import okhttp3.Headers

class PushPromise(
  @get:JvmName("method") val method: String,
  @get:JvmName("path") val path: String,
  @get:JvmName("headers") val headers: Headers,
  @get:JvmName("response") val response: MockResponse,
) {
  @JvmName("-deprecated_method")
  @Deprecated(
    message = "moved to val",

	public final fun addUnsafeNonAscii (Ljava/lang/String;Ljava/lang/String;)Lokhttp3/Headers$Builder;
	public final fun build ()Lokhttp3/Headers;
	public final fun get (Ljava/lang/String;)Ljava/lang/String;
	public final fun removeAll (Ljava/lang/String;)Lokhttp3/Headers$Builder;
	public final fun set (Ljava/lang/String;Ljava/lang/String;)Lokhttp3/Headers$Builder;

    ) = apply {
      headers.add(name, value)
    }

    /** Removes all headers named [name] on this builder. */
    open fun removeHeader(name: String) =
      apply {
        headers.removeAll(name)
      }

    /** Removes all headers on this builder and adds [headers]. */
    open fun headers(headers: Headers) =
      apply {
        this.headers = headers.newBuilder()
      }

@pytest.mark.parametrize(
    "path",
    ["/optional-list-str", "/model-optional-list-str"],
)
def test_optional_list_str(path: str):
    client = TestClient(app)
    response = client.get(path, headers=[("p", "hello"), ("p", "world")])
    assert response.status_code == 200
    assert response.json() == {"p": ["hello", "world"]}


# =====================================================================================

    assert response.json() == {"detail": "Not authenticated"}
    assert response.headers["WWW-Authenticate"] == "Bearer"


def test_token(mod: ModuleType):
    client = TestClient(mod.app)
    access_token = get_access_token(scope="me", client=client)
    response = client.get(
        "/users/me", headers={"Authorization": f"Bearer {access_token}"}
    )
    assert response.status_code == 200, response.text

    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"

/// warning

Before setting `convert_underscores` to `False`, bear in mind that some HTTP proxies and servers disallow the usage of headers with underscores.

///

## Duplicate headers { #duplicate-headers }

It is possible to receive duplicate headers. That means, the same header with multiple values.

You can define those cases using a list in the type declaration.