Adding encoding backward compatibility (#157)

Author: Pedro Faria

server/import.go

@@ -5,10 +5,11 @@ import (
 	"io"
 
 	"github.com/sirupsen/logrus"
+
 	"golang.org/x/text/transform"
 )
 
-func ImportServer(configuration, settings, event, eventRules, entrylist, bop, assistRules io.Reader) error {
+func ImportServer(configuration, settings, event, eventRules, entrylist, bop, assistRules io.ReadSeeker) error {
 	server := new(ServerSettings)
 
 	if err := importFile(configuration, &server.Configuration, configurationJsonName); err != nil {
@@ -46,14 +47,24 @@ func ImportServer(configuration, settings, event, eventRules, entrylist, bop, as
 	return nil
 }
 
-func importFile(reader io.Reader, config interface{}, filename string) error {
+func importFile(reader io.ReadSeeker, config interface{}, filename string) error {
 	r := transform.NewReader(reader, utf16Encoding.NewDecoder().Transformer)
 
 	if err := json.NewDecoder(r).Decode(config); err != nil {
-		logrus.WithError(err).
-			WithField("file", filename).
-			Error("Error unmarshalling configuration file JSON on import")
-		return err
+		if _, er := reader.Seek(0, io.SeekStart); er != nil {
+			return er
+		}
+
+		// trying decode non ut16 content
+		if err2 := json.NewDecoder(reader).Decode(config); err2 != nil {
+			logrus.WithError(err).
+				WithField("file", filename).
+				WithField("err_non_utf16", err2).
+				Error("Error unmarshalling configuration file JSON on import")
+			return err
+		} else {
+			return nil
+		}
 	}
 
 	return nil

server/list.go

@@ -2,6 +2,7 @@ package server
 
 import (
 	"encoding/json"
+	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -94,7 +95,16 @@ func loadConfigFromFile(config interface{}, path string) error {
 	r := transform.NewReader(f, utf16Encoding.NewDecoder().Transformer)
 
 	if err := json.NewDecoder(r).Decode(config); err != nil {
-		return err
+		if _, er := f.Seek(0, io.SeekStart); er != nil {
+			return er
+		}
+
+		// trying decode non ut16 content
+		if err2 := json.NewDecoder(f).Decode(config); err2 != nil {
+			return err2
+		} else {
+			return nil
+		}
 	}
 
 	return nil