Initial commit

error.go

@@ -0,0 +1,194 @@
+package jsrest
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+)
+
+var (
+	ErrBadRequest                   = NewHTTPError(http.StatusBadRequest)
+	ErrUnauthorized                 = NewHTTPError(http.StatusUnauthorized)
+	ErrPaymentRequired              = NewHTTPError(http.StatusPaymentRequired)
+	ErrForbidden                    = NewHTTPError(http.StatusForbidden)
+	ErrNotFound                     = NewHTTPError(http.StatusNotFound)
+	ErrMethodNotAllowed             = NewHTTPError(http.StatusMethodNotAllowed)
+	ErrNotAcceptable                = NewHTTPError(http.StatusNotAcceptable)
+	ErrProxyAuthRequired            = NewHTTPError(http.StatusProxyAuthRequired)
+	ErrRequestTimeout               = NewHTTPError(http.StatusRequestTimeout)
+	ErrConflict                     = NewHTTPError(http.StatusConflict)
+	ErrGone                         = NewHTTPError(http.StatusGone)
+	ErrLengthRequired               = NewHTTPError(http.StatusLengthRequired)
+	ErrPreconditionFailed           = NewHTTPError(http.StatusPreconditionFailed)
+	ErrRequestEntityTooLarge        = NewHTTPError(http.StatusRequestEntityTooLarge)
+	ErrRequestURITooLong            = NewHTTPError(http.StatusRequestURITooLong)
+	ErrUnsupportedMediaType         = NewHTTPError(http.StatusUnsupportedMediaType)
+	ErrRequestedRangeNotSatisfiable = NewHTTPError(http.StatusRequestedRangeNotSatisfiable)
+	ErrExpectationFailed            = NewHTTPError(http.StatusExpectationFailed)
+	ErrTeapot                       = NewHTTPError(http.StatusTeapot)
+	ErrMisdirectedRequest           = NewHTTPError(http.StatusMisdirectedRequest)
+	ErrUnprocessableEntity          = NewHTTPError(http.StatusUnprocessableEntity)
+	ErrLocked                       = NewHTTPError(http.StatusLocked)
+	ErrFailedDependency             = NewHTTPError(http.StatusFailedDependency)
+	ErrTooEarly                     = NewHTTPError(http.StatusTooEarly)
+	ErrUpgradeRequired              = NewHTTPError(http.StatusUpgradeRequired)
+	ErrPreconditionRequired         = NewHTTPError(http.StatusPreconditionRequired)
+	ErrTooManyRequests              = NewHTTPError(http.StatusTooManyRequests)
+	ErrRequestHeaderFieldsTooLarge  = NewHTTPError(http.StatusRequestHeaderFieldsTooLarge)
+	ErrUnavailableForLegalReasons   = NewHTTPError(http.StatusUnavailableForLegalReasons)
+
+	ErrInternalServerError           = NewHTTPError(http.StatusInternalServerError)
+	ErrNotImplemented                = NewHTTPError(http.StatusNotImplemented)
+	ErrBadGateway                    = NewHTTPError(http.StatusBadGateway)
+	ErrServiceUnavailable            = NewHTTPError(http.StatusServiceUnavailable)
+	ErrGatewayTimeout                = NewHTTPError(http.StatusGatewayTimeout)
+	ErrHTTPVersionNotSupported       = NewHTTPError(http.StatusHTTPVersionNotSupported)
+	ErrVariantAlsoNegotiates         = NewHTTPError(http.StatusVariantAlsoNegotiates)
+	ErrInsufficientStorage           = NewHTTPError(http.StatusInsufficientStorage)
+	ErrLoopDetected                  = NewHTTPError(http.StatusLoopDetected)
+	ErrNotExtended                   = NewHTTPError(http.StatusNotExtended)
+	ErrNetworkAuthenticationRequired = NewHTTPError(http.StatusNetworkAuthenticationRequired)
+)
+
+type HTTPError struct {
+	Code    int
+	Message string
+}
+
+func NewHTTPError(code int) *HTTPError {
+	return &HTTPError{
+		Code:    code,
+		Message: http.StatusText(code),
+	}
+}
+
+func (err *HTTPError) Error() string {
+	return fmt.Sprintf("[%d] %s", err.Code, err.Message)
+}
+
+type SilentJoinError struct {
+	Wraps []error
+}
+
+func SilentJoin(errs ...error) *SilentJoinError {
+	return &SilentJoinError{
+		Wraps: errs,
+	}
+}
+
+func (err *SilentJoinError) Error() string {
+	return err.Wraps[0].Error()
+}
+
+func (err *SilentJoinError) Unwrap() []error {
+	return err.Wraps
+}
+
+func WriteError(w http.ResponseWriter, err error) {
+	je := ToJSONError(err)
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(je.Code)
+
+	enc := json.NewEncoder(w)
+	_ = enc.Encode(je) //nolint:errchkjson
+}
+
+func Errorf(he *HTTPError, format string, a ...any) error {
+	err := fmt.Errorf(format, a...) //nolint:goerr113
+
+	if hasHTTPError(err) {
+		return err
+	}
+
+	return SilentJoin(err, he)
+}
+
+type JSONError struct {
+	Code     int      `json:"-"`
+	Messages []string `json:"messages"`
+}
+
+func (je *JSONError) Error() string {
+	if len(je.Messages) > 0 {
+		return je.Messages[0]
+	}
+
+	return "no error message"
+}
+
+func (je *JSONError) Unwrap() error {
+	if len(je.Messages) > 1 {
+		return &JSONError{
+			Code:     je.Code,
+			Messages: je.Messages[1:],
+		}
+	}
+
+	return nil
+}
+
+func ToJSONError(err error) *JSONError {
+	je := &JSONError{
+		Code: 500,
+	}
+	je.importError(err)
+
+	return je
+}
+
+func ReadError(in []byte) error {
+	jse := &JSONError{}
+
+	err := json.Unmarshal(in, jse)
+	if err == nil {
+		return jse
+	}
+
+	return errors.New(string(in)) //nolint:goerr113
+}
+
+type singleUnwrap interface {
+	Unwrap() error
+}
+
+type multiUnwrap interface {
+	Unwrap() []error
+}
+
+func hasHTTPError(err error) bool {
+	if _, has := err.(*HTTPError); has { //nolint:errorlint
+		return true
+	}
+
+	if unwrap, ok := err.(singleUnwrap); ok { //nolint:errorlint
+		return hasHTTPError(unwrap.Unwrap())
+	} else if unwrap, ok := err.(multiUnwrap); ok { //nolint:errorlint
+		for _, sub := range unwrap.Unwrap() {
+			if hasHTTPError(sub) {
+				return true
+			}
+		}
+	}
+
+	return false
+}
+
+func (je *JSONError) importError(err error) {
+	if he, ok := err.(*HTTPError); ok { //nolint:errorlint
+		je.Code = he.Code
+	}
+
+	if _, is := err.(*SilentJoinError); !is { //nolint:errorlint
+		je.Messages = append(je.Messages, err.Error())
+	}
+
+	if unwrap, ok := err.(singleUnwrap); ok { //nolint:errorlint
+		je.importError(unwrap.Unwrap())
+	} else if unwrap, ok := err.(multiUnwrap); ok { //nolint:errorlint
+		for _, sub := range unwrap.Unwrap() {
+			je.importError(sub)
+		}
+	}
+}