Standardmäßig gibt **FastAPI** die Responses mittels `JSONResponse` zurück.

Sie können das überschreiben, indem Sie direkt eine `Response` zurückgeben, wie in [Eine Response direkt zurückgeben](response-directly.md){.internal-link target=_blank} gezeigt.

		log.Printf("%s: contains a blank line", filename)
		exitCode = 1
	}
	if s == "" {
		log.Printf("%s: empty file", filename)
		exitCode = 1
	} else if s[len(s)-1] != '\n' {
		log.Printf("%s: missing final newline", filename)
		exitCode = 1
	}
	s = aliasReplacer.Replace(s)
	lines := strings.Split(s, "\n")
	var nonblank []string
	for i, line := range lines {
		line = strings.TrimSpace(line)

			j++
		} else {
			j--
		}
		line := tmp.String() // We use the string-valued token here, for variety.
		if s.Text() != line {
			t.Errorf("%d: bad line: %d %d\n%.100q\n%.100q\n", lineNum, len(s.Bytes()), len(line), s.Text(), line)
		}
	}
	err := s.Err()
	if err != nil {
		t.Fatal(err)
	}
}

// Test that the line splitter errors out on a long line.
func TestScanLineTooLong(t *testing.T) {

```Python hl_lines="1"
{!../../docs_src/handling_errors/tutorial001.py!}
```

### Eine `HTTPException` in Ihrem Code auslösen

`HTTPException` ist eine normale Python-<abbr title="Exception – Ausnahme, Fehler: Python-Objekt, das einen Fehler nebst Metadaten repräsentiert">Exception</abbr> mit einigen zusätzlichen Daten, die für APIs relevant sind.

Weil es eine Python-Exception ist, geben Sie sie nicht zurück, (`return`), sondern Sie lösen sie aus (`raise`).

@ElementTypesAreNonnullByDefault
abstract class LineBuffer {
  /** Holds partial line contents. */
  private StringBuilder line = new StringBuilder();
  /** Whether a line ending with a CR is pending processing. */
  private boolean sawReturn;

  /**
   * Process additional characters from the stream. When a line separator is found the contents of
   * the line and the line separator itself are passed to the abstract {@link #handleLine} method.
   *

@ElementTypesAreNonnullByDefault
abstract class LineBuffer {
  /** Holds partial line contents. */
  private StringBuilder line = new StringBuilder();
  /** Whether a line ending with a CR is pending processing. */
  private boolean sawReturn;

  /**
   * Process additional characters from the stream. When a line separator is found the contents of
   * the line and the line separator itself are passed to the abstract {@link #handleLine} method.
   *

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

   * '\n'}), a carriage return ({@code '\r'}), or a carriage return followed immediately by a
   * linefeed ({@code "\r\n"}).
   *
   * @return a {@code String} containing the contents of the line, not including any
   *     line-termination characters, or {@code null} if the end of the stream has been reached.
   * @throws IOException if an I/O error occurs
   */
  @CanIgnoreReturnValue // to skip a line
  @CheckForNull

 */
class HeadersReader(val source: BufferedSource) {
  private var headerLimit = HEADER_LIMIT.toLong()

  /** Read a single line counted against the header size limit. */
  fun readLine(): String {
    val line = source.readUtf8LineStrict(headerLimit)
    headerLimit -= line.length.toLong()
    return line
  }

  /** Reads headers or trailers. */

		}
	}
	in.Push(NewTokenizer(name, fd, fd))
}

// #line processing.
func (in *Input) line() {
	// Only need to handle Plan 9 format: #line 337 "filename"
	tok := in.Stack.Next()
	if tok != scanner.Int {
		in.expectText("expected line number after #line")
	}
	line, err := strconv.Atoi(in.Stack.Text())
	if err != nil {
		in.Error("error parsing #line (cannot happen):", err)
	}
	tok = in.Stack.Next()