val derReader = DerReader(buffer)

    derReader.read("test") { header ->
      assertThat(header.tag).isEqualTo(7L)
      assertThat(header.tagClass).isEqualTo(DerHeader.TAG_CLASS_APPLICATION)
      assertThat(header.length).isEqualTo(7L)

      derReader.read("test") { header2 ->
        assertThat(header2.tag).isEqualTo(3L)
        assertThat(header2.tagClass).isEqualTo(DerHeader.TAG_CLASS_APPLICATION)

* <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/X-Forwarded-Host" class="external-link" target="_blank">X-Forwarded-Host</a>

///

Trotzdem, da der **Anwendungsserver** nicht weiß, dass er sich hinter einem vertrauenswürdigen **Proxy** befindet, würde er diesen Headern standardmäßig nicht vertrauen.

                                "Header One": {
                                    "summary": "Header One Summary",
                                    "description": "Header One Description",
                                    "value": "header1",
                                },
                                "Header Two": {"value": "header2"},
                            },
                        }

* <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/X-Forwarded-Proto" class="external-link" target="_blank">X-Forwarded-Proto</a>
* <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/X-Forwarded-Host" class="external-link" target="_blank">X-Forwarded-Host</a>

///

### Proxy-Forwarded-Header aktivieren { #enable-proxy-forwarded-headers }

// getCanonicalHeaders generate a list of request headers with their values
func getCanonicalHeaders(signedHeaders http.Header) string {
	var headers []string
	vals := make(http.Header, len(signedHeaders))
	for k, vv := range signedHeaders {
		k = strings.ToLower(k)
		headers = append(headers, k)
		vals[k] = vv
	}
	sort.Strings(headers)

	var buf bytes.Buffer
	for _, k := range headers {
		buf.WriteString(k)
		buf.WriteByte(':')

# Header 参数

定义 `Header` 参数的方式与定义 `Query`、`Path`、`Cookie` 参数相同。

## 导入 `Header`

首先，导入 `Header`：

{* ../../docs_src/header_params/tutorial001_an_py310.py hl[3] *}

## 声明 `Header` 参数

然后，使用和 `Path`、`Query`、`Cookie` 一样的结构定义 header 参数。

第一个值是默认值，还可以传递所有验证参数或注释参数：

{* ../../docs_src/header_params/tutorial001_an_py310.py hl[9] *}

/// note | 技术细节

`Header` 是 `Path`、`Query`、`Cookie` 的**兄弟类**，都继承自共用的 `Param` 类。

    response = client.get(path, headers=[("p", "hello"), ("p", "world")])
    assert response.status_code == 200
    assert response.json() == {"p": ["hello", "world"]}


# =====================================================================================
# Alias


@app.get("/optional-list-alias")
async def read_optional_list_alias(
    p: Annotated[Optional[list[str]], Header(alias="p_alias")] = None,
):

                "msg": "Field required",
                "input": AnyThing,
            }
        ]
    }


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

      )

    fun http2HeadersList(request: Request): List<Header> {
      val headers = request.headers
      val result = ArrayList<Header>(headers.size + 4)
      result.add(Header(TARGET_METHOD, request.method))
      result.add(Header(TARGET_PATH, RequestLine.requestPath(request.url)))
      val host = request.header("Host")
      if (host != null) {
        result.add(Header(TARGET_AUTHORITY, host)) // Optional.
      }

        return contentException;
    }

    /**
     * Sets the headers for the response.
     *
     * @param headers the headers to set.
     */
    public void setHeaders(final Map<String, List<String>> headers) {
        if (headers != null) {
            final Map<String, List<String>> map = new HashMap<>();
            headers.entrySet().stream().filter(e -> e.getKey() != null).forEach(