context   string // additional error context
	pos       errPos
	atChar    byte
	readerErr error // underlying reader error, if any
}

// ReaderErr returns the underlying error.
func (e DecoderError) ReaderErr() error { return e.readerErr }

// Error returns a string representation of the error.
func (e DecoderError) Error() string {
	loc := fmt.Sprintf("%s [%d,%d]", quoteChar(e.atChar), e.pos[0], e.pos[1])

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` { #use-httpexception }

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

### Import `HTTPException` { #import-httpexception }

type ChecksumMismatch struct {
	Want string
	Got  string
}

func (e ChecksumMismatch) Error() string {
	return "Bad checksum: Want " + e.Want + " does not match calculated " + e.Got
}

// IsChecksumMismatch matches if 'err' is hash.ChecksumMismatch
func IsChecksumMismatch(err error) bool {
	var herr ChecksumMismatch
	return errors.As(err, &herr)

	return errors.Is(err, syscall.EXDEV)
}

// Check if given error corresponds to too many open files
func isSysErrTooManyFiles(err error) bool {
	return errors.Is(err, syscall.ENFILE) || errors.Is(err, syscall.EMFILE)
}

func osIsNotExist(err error) bool {
	return errors.Is(err, os.ErrNotExist)
}

func osIsPermission(err error) bool {

// error returned when temporary account is not found
var errNoSuchTempAccount = errors.New("Specified temporary account does not exist")

// error returned when access key is not found
var errNoSuchAccessKey = errors.New("Specified access key does not exist")

// error returned in IAM subsystem when an account doesn't exist.

func Errorf(format string, a ...any) error {
	e := fmt.Errorf(format, a...)
	ee := Error{}
	ee.msg = e.Error()
	ee.cause = errors.Unwrap(e)
	return ee
}

// Unwrap the internal error.
func (e Error) Unwrap() error { return e.cause }

// Error 'error' compatible method.
func (e Error) Error() string {
	if e.msg == "" {
		return "crypto: cause <nil>"
	}
	return e.msg
}

var (

        }
    ]
}
```

you will get a text version, with:

```
Validation errors:
Field: ('path', 'item_id'), Error: Input should be a valid integer, unable to parse string as an integer
```

### Override the `HTTPException` error handler { #override-the-httpexception-error-handler }

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

package grid

import (
	"errors"
	"fmt"
)

var (
	// ErrUnknownHandler is returned when an unknown handler is requested.
	ErrUnknownHandler = errors.New("unknown mux handler")

	// ErrHandlerAlreadyExists is returned when a handler is already registered.
	ErrHandlerAlreadyExists = errors.New("mux handler already exists")

	// ErrSubQueryRequired sub query required
	ErrSubQueryRequired = errors.New("sub query required")
	// ErrInvalidData unsupported data
	ErrInvalidData = errors.New("unsupported data")
	// ErrUnsupportedDriver unsupported driver
	ErrUnsupportedDriver = errors.New("unsupported driver")
	// ErrRegistered registered
	ErrRegistered = errors.New("registered")

	}
)

// Error is a KMS error that can be translated into an S3 API error.
//
// It does not implement the standard error Unwrap interface for
// better error log messages.
type Error struct {
	Code    int    // The HTTP status code returned to the client
	APICode string // The API error code identifying the error
	Err     string // The error message returned to the client
	Cause   error  // Optional, lower level error cause.
}