feat(pkg): added err message and http message mapper

pkg/errmsg/message.go

@@ -0,0 +1,6 @@
+package errmsg
+
+const (
+	ErrorMsgNotFound           = "record not found"
+	ErrorMsgSomethingWentWrong = "something went wrong"
+)

pkg/httpmsg/mapper.go

@@ -0,0 +1,41 @@
+package httpmsg
+
+import (
+	"git.gocasts.ir/ebhomengo/niki/pkg/errmsg"
+	"git.gocasts.ir/ebhomengo/niki/pkg/richerror"
+	"net/http"
+)
+
+func Error(err error) (message string, code int) {
+	switch err.(type) {
+	case richerror.RichError:
+		re := err.(richerror.RichError)
+		msg := re.Message()
+
+		code := mapKindToHTTPStatusCode(re.Kind())
+
+		// we should not expose unexpected error messages
+		if code >= 500 {
+			msg = errmsg.ErrorMsgSomethingWentWrong
+		}
+
+		return msg, code
+	default:
+		return err.Error(), http.StatusBadRequest
+	}
+}
+
+func mapKindToHTTPStatusCode(kind richerror.Kind) int {
+	switch kind {
+	case richerror.KindInvalid:
+		return http.StatusUnprocessableEntity
+	case richerror.KindNotFound:
+		return http.StatusNotFound
+	case richerror.KindForbidden:
+		return http.StatusForbidden
+	case richerror.KindUnexpected:
+		return http.StatusInternalServerError
+	default:
+		return http.StatusBadRequest
+	}
+}