private fun String.asciiToLowercase(): String =
    when {
      isAscii() -> lowercase(Locale.US)

      // This is an ASCII string.
      else -> this
    }

  /** Returns true if the [String] is ASCII encoded (0-127). */
  private fun String.isAscii() = length == utf8Size().toInt()

  /**
   * Returns true if [hostname] matches the domain name [pattern].
   *
   * @param hostname lower-case host name.

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[28:31] hl[29] *}

### Dönüş Tipi Olmadan { #no-return-type }

Dönüş tipini belirtmeyebilirsiniz. FastAPI, veriyi dönüştürmek ve göndermek için [`jsonable_encoder`](./encoder.md) kullanır.

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[34:37] hl[35] *}

## `ServerSentEvent` { #serversentevent }

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[28:31] hl[29] *}

### Без объявленного типа возврата { #no-return-type }

Вы также можете опустить тип возврата. FastAPI использует [`jsonable_encoder`](./encoder.md) для преобразования данных и их отправки.

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[34:37] hl[35] *}

## `ServerSentEvent` { #serversentevent }

import okhttp3.internal.http2.Header.Companion.TARGET_SCHEME_UTF8
import okhttp3.internal.immutableListOf
import okio.Sink
import okio.Socket
import okio.Source

/** Encode requests and responses using HTTP/2 frames. */
class Http2ExchangeCodec(
  client: OkHttpClient,
  override val carrier: Carrier,
  private val chain: RealInterceptorChain,
  private val http2Connection: Http2Connection,

		// io.Discard is just used to create the writer. Actual destination
		// writer is set later by Reset() before using it.
		return bufio.NewWriter(xioutil.Discard)
	},
}

// UnmarshalXML - decodes XML data.
func (c *CompressionType) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
	var s string
	if err := d.DecodeElement(&s, &start); err != nil {
		return errMalformedXML(err)
	}

                    if (CharUtil.isUrlChar(c) || c == ' ') {
                        buf.append(c);
                    } else {
                        try {
                            buf.append(URLEncoder.encode(String.valueOf(c), Constants.UTF_8));
                        } catch (final UnsupportedEncodingException e) {
                            // NOP
                        }
                    }
                }

        dstIndex += 1;

        // Write SMB2_RDMA_TRANSFORM if using RDMA channel
        if (rdmaChannelInfo != null && channel == Smb2Constants.SMB2_CHANNEL_RDMA_V1) {
            rdmaChannelInfo.encode(dst, dstIndex);
            dstIndex += 16;
        }

        return dstIndex - start;
    }

    /**
     * {@inheritDoc}
     *

				return
			}
		default:
			err = dc.Skip()
			if err != nil {
				err = msgp.WrapError(err)
				return
			}
		}
	}
	return
}

// EncodeMsg implements msgp.Encodable
func (z *WalkDirOptions) EncodeMsg(en *msgp.Writer) (err error) {
	// map header, size 8
	// write "Bucket"
	err = en.Append(0x88, 0xa6, 0x42, 0x75, 0x63, 0x6b, 0x65, 0x74)
	if err != nil {
		return
	}

	// Total object size.
	Size int64

	// Actual size is the real size of the object uploaded by client.
	ActualSize *int64

	// IsDir indicates if the object is prefix.
	IsDir bool

	// Hex encoded unique entity tag of the object.
	ETag string

	// Version ID of this object.
	VersionID string

	// IsLatest indicates if this is the latest current version

關於如何把資料傳給後端（使用 `httpx` 或 `TestClient`），更多資訊請參考 [HTTPX 文件](https://www.python-httpx.org)。

/// info

請注意，`TestClient` 接收的是可轉為 JSON 的資料，而不是 Pydantic models。

如果你的測試裡有一個 Pydantic model，並想在測試時把它的資料送給應用，你可以使用[JSON 相容編碼器](encoder.md)中介紹的 `jsonable_encoder`。

///

## 執行 { #run-it }

接下來，你只需要安裝 `pytest`。

請先建立並啟用一個[虛擬環境](../virtual-environments.md)，然後安裝，例如：

<div class="termy">

```console