It might also help avoid confusion for new developers that see an unused parameter in your code and could think it's unnecessary.

///

/// info

In this example we use invented custom headers `X-Key` and `X-Token`.

But in real cases, when implementing security, you would get more benefits from using the integrated [Security utilities (the next chapter)](../security/index.md){.internal-link target=_blank}.

///

    *,
    settings: Settings,
    query: str,
    after: str | None = None,
) -> dict[str, Any]:
    headers = {"Authorization": f"token {settings.github_token.get_secret_value()}"}
    variables = {"after": after}
    response = httpx.post(
        github_graphql_url,
        headers=headers,
        timeout=settings.httpx_timeout,
        json={"query": query, "variables": variables, "operationName": "Q"},
    )

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

  forObsoleteRfc2965: Boolean,
): String = cookie.toString(forObsoleteRfc2965)

internal fun addHeaderLenient(
  builder: Headers.Builder,
  line: String,
): Headers.Builder = builder.addLenient(line)

internal fun addHeaderLenient(
  builder: Headers.Builder,
  name: String,
  value: String,
): Headers.Builder = builder.addLenient(name, value)

internal fun cacheGet(
  cache: Cache,
  request: Request,

* 创建一个允许的源列表（由字符串组成）。
* 将其作为「中间件」添加到你的 **FastAPI** 应用中。

你也可以指定后端是否允许：

* 凭证（授权 headers，Cookies 等）。
* 特定的 HTTP 方法（`POST`，`PUT`）或者使用通配符 `"*"` 允许所有方法。
* 特定的 HTTP headers 或者使用通配符 `"*"` 允许所有 headers。

{* ../../docs_src/cors/tutorial001.py hl[2,6:11,13:19] *}

默认情况下，这个 `CORSMiddleware` 实现所使用的默认参数较为保守，所以你需要显式地启用特定的源、方法或者 headers，以便浏览器能够在跨域上下文中使用它们。

支持以下参数：

		t.Fatalf("no error should happen when migrate scanner, valuer struct, got error %v", err)
	}

	data := ScannerValuerStruct{
		Name:     sql.NullString{String: "name", Valid: true},
		Gender:   &sql.NullString{String: "M", Valid: true},
		Age:      sql.NullInt64{Int64: 18, Valid: true},
		Male:     sql.NullBool{Bool: true, Valid: true},
		Height:   sql.NullFloat64{Float64: 1.8888, Valid: true},

## Version 4.9.2

_2021-09-30_

 *  Fix: Don't include potentially-sensitive header values in `Headers.toString()` or exceptions.
    This applies to `Authorization`, `Cookie`, `Proxy-Authorization`, and `Set-Cookie` headers.
 *  Fix: Don't crash with an `InaccessibleObjectException` when running on JDK17+ with strong
    encapsulation enabled.

type Identity struct {
	Type        string `json:"type"`
	PrincipalID string `json:"principalId"`
	AccessKeyID string `json:"accessKeyId"`
}

// UserRequest user request headers
type UserRequest struct {
	URL     string      `json:"url"`
	Headers http.Header `json:"headers"`
}

// GetObjectContext provides the necessary details to perform
// download of the object, and return back the processed response
// to the server.

        // Mock getHeaderFields to return our headers
        Map<String, List<String>> allHeaders = headers != null ? new HashMap<>(headers) : new HashMap<>();
        allHeaders.put(null, Collections.singletonList(statusLine)); // Status line
        when(conn.getHeaderFields()).thenReturn(allHeaders);

        // Mock individual header access by both string key and index
        if (headers != null) {
            // Mock by header name

Mas lembre-se que quando você importa `Query`, `Path`, `Header`, e outras de `fastapi`, elas são na verdade funções que retornam classes especiais.

///

/// info | Informação

Para declarar headers, você precisa usar `Header`, caso contrário, os parâmetros seriam interpretados como parâmetros de consulta.

///

## Conversão automática { #automatic-conversion }