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

Você se lembra de todos aqueles erros (e piadas) a respeito do "**404 Not Found**"?

## Use o `HTTPException`

Para retornar ao cliente *responses* HTTP com erros, use o `HTTPException`.

### Import `HTTPException`

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

```
1 validation error
path -> item_id
  value is not a valid integer (type=type_error.integer)
```

#### `RequestValidationError` vs. `ValidationError`

!!! warning "Achtung"
    Das folgende sind technische Details, die Sie überspringen können, wenn sie für Sie nicht wichtig sind.

pkg p1, type EmbedURLPtr struct
pkg p1, type EmbedURLPtr struct, embedded *URL
pkg p1, type Embedded struct
pkg p1, type Error interface { Error, Temporary }
pkg p1, type Error interface, Error() string
pkg p1, type Error interface, Temporary() bool
pkg p1, type FuncType func(int, int, string) (*B, error)
pkg p1, type I interface, Get(string) int64
pkg p1, type I interface, Get //deprecated
pkg p1, type I interface, GetNamed(string) int64

pkg net/netip, func ParseAddr(string) (Addr, error)
pkg net/netip, func ParseAddrPort(string) (AddrPort, error)
pkg net/netip, func ParsePrefix(string) (Prefix, error)
pkg net/netip, func PrefixFrom(Addr, int) Prefix
pkg net/netip, method (*Addr) UnmarshalBinary([]uint8) error
pkg net/netip, method (*Addr) UnmarshalText([]uint8) error
pkg net/netip, method (*AddrPort) UnmarshalBinary([]uint8) error

### Override the `HTTPException` error handler

The same way, you can override the `HTTPException` handler.

For example, you could want to return a plain text response instead of JSON for these errors:

```Python hl_lines="3-4  9-11  22"
{!../../../docs_src/handling_errors/tutorial004.py!}
```

pkg bufio, method (ReadWriter) ReadString(uint8) (string, error)
pkg bufio, method (ReadWriter) UnreadByte() error
pkg bufio, method (ReadWriter) UnreadRune() error
pkg bufio, method (ReadWriter) Write([]uint8) (int, error)
pkg bufio, method (ReadWriter) WriteByte(uint8) error
pkg bufio, method (ReadWriter) WriteRune(int32) (int, error)
pkg bufio, method (ReadWriter) WriteString(string) (int, error)
pkg bufio, type ReadWriter struct

pkg image/color, var NYCbCrAModel Model
pkg math/big, method (*Float) MarshalText() ([]uint8, error)
pkg math/big, method (*Float) UnmarshalText([]uint8) error
pkg math/big, method (*Int) Append([]uint8, int) []uint8
pkg math/big, method (*Int) Text(int) string
pkg math/rand, func Read([]uint8) (int, error)
pkg math/rand, method (*Rand) Read([]uint8) (int, error)
pkg net, type DNSError struct, IsTemporary bool

      }
    }

    override fun iterator() = error("unsupported")

    override fun offer(e: T) = error("unsupported")

    override fun peek(): T = error("unsupported")

    override fun offer(
      element: T,
      timeout: Long,
      unit: TimeUnit,
    ) = error("unsupported")

    override fun take() = error("unsupported")

    message = "moved to val",
    replaceWith = ReplaceWith(expression = "noCache"),
    level = DeprecationLevel.ERROR,
  )
  fun noCache(): Boolean = noCache

  @JvmName("-deprecated_noStore")
  @Deprecated(
    message = "moved to val",
    replaceWith = ReplaceWith(expression = "noStore"),
    level = DeprecationLevel.ERROR,
  )
  fun noStore(): Boolean = noStore

  @JvmName("-deprecated_maxAgeSeconds")
  @Deprecated(

    replaceWith = ReplaceWith(expression = "tlsVersion"),
    level = DeprecationLevel.ERROR,
  )
  fun tlsVersion(): TlsVersion = tlsVersion

  @JvmName("-deprecated_cipherSuite")
  @Deprecated(
    message = "moved to val",
    replaceWith = ReplaceWith(expression = "cipherSuite"),
    level = DeprecationLevel.ERROR,
  )
  fun cipherSuite(): CipherSuite = cipherSuite

  @JvmName("-deprecated_peerCertificates")