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!}
```

		statusCode: 400,
		cause:      err,
	}
}

func errColumnTooLong(err error) *s3Error {
	return &s3Error{
		code:       "ColumnTooLong",
		message:    "The length of a column in the result is greater than maxCharsPerColumn of 1 MB.",
		statusCode: 400,
		cause:      err,
	}
}

func errOverMaxColumn(err error) *s3Error {
	return &s3Error{
		code:       "OverMaxColumn",

	return "Object name invalid: " + e.Bucket + "/" + e.Object
}

// Error returns string an error formatted as the given text.
func (e ObjectNameTooLong) Error() string {
	return "Object name too long: " + e.Bucket + "/" + e.Object
}

// Error returns string an error formatted as the given text.
func (e ObjectNamePrefixAsSlash) Error() string {

```
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.

	if err := DB.Create(&data).Error; err != nil {
		t.Errorf("Should got no error when creating data, but got %v", err)
	}

	if err := DB.Model(&data).Update("password", EncryptedData("xnewpass")).Error; err == nil {
		t.Errorf("Should failed to update data with invalid data")
	}

	if err := DB.Model(&data).Update("password", EncryptedData("newpass")).Error; err != nil {

	if err := DB.Transaction(func(tx *gorm.DB) error {
		return nil
	}); err == nil {
		t.Errorf("should returns error when commit with closed conn, got error %v", err)
	}

	if err := DB.Session(&gorm.Session{PrepareStmt: true}).Transaction(func(tx *gorm.DB) error {
		return nil
	}); err == nil {
		t.Errorf("should returns error when commit with closed conn, got error %v", err)
	}
}

	if err := DB.Model(&User{}).Update("name", "jinzhu").Error; err == nil || !errors.Is(err, gorm.ErrMissingWhereClause) {
		t.Errorf("should returns missing WHERE clause while updating error, got err %v", err)
	}

	if err := DB.Session(&gorm.Session{AllowGlobalUpdate: true}).Model(&User{}).Update("name", "jinzhu").Error; err != nil {
		t.Errorf("should returns no error while enable global update, but got err %v", err)
	}
}

		t.Errorf("no error should happen when auto migrate, but got %v", err)
	}

	if err := DB.Create(&EmptyStruct{}).Error; err != nil {
		t.Errorf("No error should happen when creating user, but got %v", err)
	}
}

func TestCreateEmptySlice(t *testing.T) {
	data := []User{}
	if err := DB.Create(&data).Error; err != gorm.ErrEmptySlice {
		t.Errorf("no data should be created, got %v", err)
	}

		// printed once.
		if once {
			return
		}
		// once not set, check if same error occurred 3 times in
		// a row, then make sure we print it to call attention.
		if m[err.Error()] > 2 {
			peersLogAlwaysIf(ctx, fmt.Errorf("Following error has been printed %d times.. %w", m[err.Error()], err))
			// Reduce the count to introduce further delay in printing
			// but let it again print after the 2th attempt
			m[err.Error()]--

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

#### `RequestValidationError` или `ValidationError`

!!! warning "Внимание"
    Это технические детали, которые можно пропустить, если они не важны для вас сейчас.