public static final int ERR_SSN_SRVC = 0x02;

    // name service error codes
    public static final int FMT_ERR = 0x1;
    public static final int SRV_ERR = 0x2;
    public static final int IMP_ERR = 0x4;
    public static final int RFS_ERR = 0x5;
    public static final int ACT_ERR = 0x6;
    public static final int CFT_ERR = 0x7;

    // session service error codes
    public static final int CONNECTION_REFUSED    = -1; 

    }
  }

  private fun shouldIgnoreAndWaitForRealResponse(
    code: Int,
    exchange: Exchange,
  ): Boolean =
    when {
      // Server sent a 100-continue even though we did not request one. Try again to read the
      // actual response status.
      code == 100 -> true

      // Handle Processing (102) & Early Hints (103) and any new codes without failing
      // 100 and 101 are the exceptions with different meanings

The status codes in the 400 range mean that there was an error from the client.

Remember all those **"404 Not Found"** errors (and jokes)?

## Use `HTTPException`

To return HTTP responses with errors to the client you use `HTTPException`.

### Import `HTTPException`

```Python hl_lines="1"

///

## Schreiben des Codes, der den Callback dokumentiert

Dieser Code wird nicht in Ihrer Anwendung ausgeführt, wir benötigen ihn nur, um zu *dokumentieren*, wie diese *externe API* aussehen soll.

frontend-app@1.0.0 generate-client /home/user/code/frontend-app
> openapi-ts --input http://localhost:8000/openapi.json --output ./src/client --client axios
```

</div>

Dieser Befehl generiert Code in `./src/client` und verwendet intern `axios` (die Frontend-HTTP-Bibliothek).

### Den Client-Code ausprobieren

}

// STSError structure
type STSError struct {
	Code           string
	Description    string
	HTTPStatusCode int
}

// STSErrorResponse - error response format
type STSErrorResponse struct {
	XMLName xml.Name `xml:"https://sts.amazonaws.com/doc/2011-06-15/ ErrorResponse" json:"-"`
	Error   struct {
		Type    string `xml:"Type"`
		Code    string `xml:"Code"`
		Message string `xml:"Message"`
	} `xml:"Error"`

	return blobBody
}

// WriteHeader - writes http status code
func (lrw *ResponseRecorder) WriteHeader(code int) {
	if !lrw.headersLogged {
		lrw.ttfbHeader = time.Now().UTC().Sub(lrw.StartTime)
		lrw.StatusCode = code
		lrw.writeHeaders(&lrw.headers, code, lrw.ResponseWriter.Header())
		lrw.headersLogged = true
		lrw.ResponseWriter.WriteHeader(code)
	}
}

// Flush - Calls the underlying Flush.

* **Uvicorn**:
    * Bietet die beste Leistung, da außer dem Server selbst nicht viel zusätzlicher Code vorhanden ist.

    end

    rect rgba(0, 255, 0, .1)
        code ->> function: say_hi(name="Rick")
        function ->> execute: führe Code der Funktion aus
        execute ->> code: gib das Resultat zurück
    end

    rect rgba(0, 255, 0, .1)
        code ->> function: say_hi(name="Rick", salutation="Mr.")
        function ->> execute: führe Code der Funktion aus

* etc.


Nesses casos, você normalmente retornaria um **HTTP status code** próximo ao status code na faixa do status code **400** (do 400 ao 499).

Isso é bastante similar ao caso do HTTP status code 200 (do 200 ao 299). Esses "200" status codes significam que, de algum modo, houve sucesso na requisição.

Os status codes na faixa dos 400 significam que houve um erro por parte do cliente.