feat: added API gateway

internal/gw/domain/errors.go

@@ -0,0 +1,137 @@
+package domain
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+)
+
+var (
+	ErrUnauthorized      = errors.New("unauthorized")
+	ErrForbidden         = errors.New("forbidden")
+	ErrNotFound          = errors.New("not found")
+	ErrBadRequest        = errors.New("bad request")
+	ErrInternalServer    = errors.New("internal server error")
+	ErrConflict          = errors.New("conflict")
+	ErrInvalidToken      = errors.New("invalid token")
+	ErrMissingAuthHeader = errors.New("missing authorization header")
+	ErrInvalidFile       = errors.New("invalid file")
+	ErrFileTooLarge      = errors.New("file too large")
+)
+
+type AppError struct {
+	Err        error
+	Message    string
+	StatusCode int
+}
+
+func (e *AppError) Error() string {
+	if e.Message != "" {
+		return e.Message
+	}
+	if e.Err != nil {
+		return e.Err.Error()
+	}
+	return "unknown error"
+}
+
+func NewAppError(err error, message string, statusCode int) *AppError {
+	return &AppError{
+		Err:        err,
+		Message:    message,
+		StatusCode: statusCode,
+	}
+}
+
+func NewBadRequestError(message string) *AppError {
+	return &AppError{
+		Err:        ErrBadRequest,
+		Message:    message,
+		StatusCode: http.StatusBadRequest,
+	}
+}
+
+func NewUnauthorizedError(message string) *AppError {
+	return &AppError{
+		Err:        ErrUnauthorized,
+		Message:    message,
+		StatusCode: http.StatusUnauthorized,
+	}
+}
+
+func NewForbiddenError(message string) *AppError {
+	return &AppError{
+		Err:        ErrForbidden,
+		Message:    message,
+		StatusCode: http.StatusForbidden,
+	}
+}
+
+func NewNotFoundError(message string) *AppError {
+	return &AppError{
+		Err:        ErrNotFound,
+		Message:    message,
+		StatusCode: http.StatusNotFound,
+	}
+}
+
+func NewConflictError(message string) *AppError {
+	return &AppError{
+		Err:        ErrConflict,
+		Message:    message,
+		StatusCode: http.StatusConflict,
+	}
+}
+
+func NewInternalServerError(message string) *AppError {
+	return &AppError{
+		Err:        ErrInternalServer,
+		Message:    message,
+		StatusCode: http.StatusInternalServerError,
+	}
+}
+
+type ErrorResponse struct {
+	Error   string `json:"error"`
+	Message string `json:"message,omitempty"`
+	Details string `json:"details,omitempty"`
+}
+
+func NewErrorResponse(err error, message string) *ErrorResponse {
+	errMsg := "internal server error"
+	if err != nil {
+		errMsg = err.Error()
+	}
+
+	return &ErrorResponse{
+		Error:   errMsg,
+		Message: message,
+	}
+}
+
+func GRPCErrorToHTTPStatus(err error) int {
+	if err == nil {
+		return http.StatusOK
+	}
+
+	errMsg := err.Error()
+
+	switch {
+	case contains(errMsg, "not found"):
+		return http.StatusNotFound
+	case contains(errMsg, "already exists"), contains(errMsg, "conflict"):
+		return http.StatusConflict
+	case contains(errMsg, "invalid"), contains(errMsg, "bad request"):
+		return http.StatusBadRequest
+	case contains(errMsg, "unauthorized"), contains(errMsg, "unauthenticated"):
+		return http.StatusUnauthorized
+	case contains(errMsg, "forbidden"), contains(errMsg, "permission denied"):
+		return http.StatusForbidden
+	default:
+		return http.StatusInternalServerError
+	}
+}
+
+func contains(s, substr string) bool {
+	return len(s) >= len(substr) && (s == substr || fmt.Sprintf("%s", s) != s)
+}