### Expiry or removal events

Avant de définir `convert_underscores` sur `False`, gardez à l'esprit que certains proxies et serveurs HTTP interdisent l'utilisation d'en-têtes contenant des traits bas.

///

## Gérer les en-têtes dupliqués { #duplicate-headers }

Il est possible de recevoir des en-têtes en double. Autrement dit, le même en-tête avec plusieurs valeurs.

Vous pouvez définir ces cas à l'aide d'une liste dans la déclaration de type.

    assert response.status_code == 200, response.text
    assert response.headers["content-type"] == "text/html; charset=utf-8"
    assert "window.opener.swaggerUIRedirectOauth2" in response.text


def test_redoc():
    response = client.get("/redoc")
    assert response.status_code == 200, response.text
    assert response.headers["content-type"] == "text/html; charset=utf-8"
    assert "redoc@2" in response.text

 * limitations under the License.
 */
package okhttp3.internal.connection

import java.io.IOException
import java.net.ProtocolException
import okhttp3.EventListener
import okhttp3.Headers
import okhttp3.Request
import okhttp3.Response
import okhttp3.ResponseBody
import okhttp3.internal.http.ExchangeCodec
import okhttp3.internal.http.RealResponseBody
import okio.Buffer
import okio.ForwardingSink

			return
		}
		if globalBucketVersioningSys.PrefixEnabled(srcBucket, srcObject) && gr != nil {
			// Versioning enabled quite possibly object is deleted might be delete-marker
			// if present set the headers, no idea why AWS S3 sets these headers.
			if gr.ObjInfo.VersionID != "" && gr.ObjInfo.DeleteMarker {
				w.Header()[xhttp.AmzVersionID] = []string{gr.ObjInfo.VersionID}

Cache Miss will be typical if the item has not been read from the network, is uncacheable, or is past it's
lifetime based on Response cache headers.

 - CallStart
 - **CacheMiss**
 - ProxySelectStart
 - ... Standard Events ...
 - CallEnd

### Conditional Cache Hit

# Using the Request Directly { #using-the-request-directly }

Up to now, you have been declaring the parts of the request that you need with their types.

Taking data from:

* The path as parameters.
* Headers.
* Cookies.
* etc.

And by doing so, **FastAPI** is validating that data, converting it and generating documentation for your API automatically.

But there are situations where you might need to access the `Request` object directly.

/// warning | Uyarı

`convert_underscores`'u `False` yapmadan önce, bazı HTTP proxy'lerinin ve server'ların underscore içeren header'ların kullanımına izin vermediğini unutmayın.

///

## Yinelenen Header'lar { #duplicate-headers }

Yinelenen header'lar almak mümkündür. Yani aynı header'ın birden fazla değeri olabilir.

Bu tür durumları, type tanımında bir list kullanarak belirtebilirsiniz.

///

### `Response` { #response }

其他全部的响应都继承自主类 `Response`。

你可以直接返回它。

`Response` 类接受如下参数：

* `content` - 一个 `str` 或者 `bytes`。
* `status_code` - 一个 `int` 类型的 HTTP 状态码。
* `headers` - 一个由字符串组成的 `dict`。
* `media_type` - 一个给出媒体类型的 `str`，比如 `"text/html"`。

FastAPI（实际上是 Starlette）将自动包含 Content-Length 的头。它还将包含一个基于 `media_type` 的 Content-Type 头，并为文本类型附加一个字符集。

但在實際情況下，當你實作安全機制時，使用整合的 [Security utilities（下一章）](../security/index.md) 會獲得更多好處。

///

## 依賴的錯誤與回傳值 { #dependencies-errors-and-return-values }

你可以使用與平常相同的依賴函式。

### 依賴的需求 { #dependency-requirements }

它們可以宣告請求需求（例如標頭（headers））或其他子依賴：

{* ../../docs_src/dependencies/tutorial006_an_py310.py hl[8,13] *}

### 拋出例外 { #raise-exceptions }

這些依賴可以 `raise` 例外，與一般依賴相同：

{* ../../docs_src/dependencies/tutorial006_an_py310.py hl[10,15] *}