Sessions: locale-aware csv formatting (#5136)

api/api.go

@@ -232,5 +232,5 @@ type FeatureDescriber interface {
 
 // CsvWriter converts to csv
 type CsvWriter interface {
-	WriteCsv(context.Context, io.Writer)
+	WriteCsv(context.Context, io.Writer) error
 }

core/db/session.go

@@ -5,14 +5,16 @@ import (
 	"encoding/csv"
 	"fmt"
 	"io"
-	"strconv"
 	"strings"
 	"time"
 
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/util/locale"
 	"github.com/fatih/structs"
 	"github.com/nicksnyder/go-i18n/v2/i18n"
+	"golang.org/x/text/language"
+	"golang.org/x/text/message"
+	"golang.org/x/text/number"
 )
 
 // Session is a single charging session
@@ -23,7 +25,7 @@ type Session struct {
 	Loadpoint     string    `json:"loadpoint"`
 	Identifier    string    `json:"identifier"`
 	Vehicle       string    `json:"vehicle"`
-	Odometer      float64   `json:"odometer"`
+	Odometer      float64   `json:"odometer" format:"int"`
 	MeterStart    float64   `json:"meterStart" csv:"Meter Start (kWh)" gorm:"column:meter_start_kwh"`
 	MeterStop     float64   `json:"meterStop" csv:"Meter Stop (kWh)" gorm:"column:meter_end_kwh"`
 	ChargedEnergy float64   `json:"chargedEnergy" csv:"Charged Energy (kWh)" gorm:"column:charged_kwh"`
@@ -43,7 +45,7 @@ type Sessions []Session
 
 var _ api.CsvWriter = (*Sessions)(nil)
 
-func (t *Sessions) writeHeader(ctx context.Context, ww *csv.Writer) {
+func (t *Sessions) writeHeader(ctx context.Context, ww *csv.Writer) error {
 	localizer := locale.Localizer
 	if val := ctx.Value(locale.Locale).(string); val != "" {
 		localizer = i18n.NewLocalizer(locale.Bundle, val, locale.Language)
@@ -70,21 +72,28 @@ func (t *Sessions) writeHeader(ctx context.Context, ww *csv.Writer) {
 
 		row = append(row, caption)
 	}
-	_ = ww.Write(row)
+
+	return ww.Write(row)
 }
 
-func (t *Sessions) writeRow(ww *csv.Writer, r Session) {
+func (t *Sessions) writeRow(ww *csv.Writer, mp *message.Printer, r Session) error {
 	var row []string
 	for _, f := range structs.Fields(r) {
 		if f.Tag("csv") == "-" {
 			continue
 		}
 
 		var val string
+		format := f.Tag("format")
 
 		switch v := f.Value().(type) {
 		case float64:
-			val = strconv.FormatFloat(v, 'f', 3, 64)
+			switch format {
+			case "int":
+				val = mp.Sprint(number.Decimal(v, number.MaxFractionDigits(0)))
+			default:
+				val = mp.Sprint(number.Decimal(v, number.MaxFractionDigits(3)))
+			}
 		case time.Time:
 			if !v.IsZero() {
 				val = v.Local().Format("2006-01-02 15:04:05")
@@ -96,17 +105,45 @@ func (t *Sessions) writeRow(ww *csv.Writer, r Session) {
 		row = append(row, val)
 	}
 
-	_ = ww.Write(row)
+	return ww.Write(row)
 }
 
 // WriteCsv implements the api.CsvWriter interface
-func (t *Sessions) WriteCsv(ctx context.Context, w io.Writer) {
+func (t *Sessions) WriteCsv(ctx context.Context, w io.Writer) error {
+	if _, err := w.Write([]byte{0xEF, 0xBB, 0xBF}); err != nil {
+		return err
+	}
+
+	// get context language
+	lang := locale.Language
+	if language, ok := ctx.Value(locale.Locale).(string); ok && language != "" {
+		lang = language
+	}
+
+	tag, err := language.Parse(lang)
+	if err != nil {
+		return err
+	}
+
 	ww := csv.NewWriter(w)
-	t.writeHeader(ctx, ww)
 
+	// set separator according to locale
+	if b, _ := tag.Base(); b.String() == language.German.String() {
+		ww.Comma = ';'
+	}
+
+	if err := t.writeHeader(ctx, ww); err != nil {
+		return err
+	}
+
+	mp := message.NewPrinter(tag)
 	for _, r := range *t {
-		t.writeRow(ww, r)
+		if err := t.writeRow(ww, mp, r); err != nil {
+			return err
+		}
 	}
 
 	ww.Flush()
+
+	return ww.Error()
 }

server/http_handler.go

@@ -19,6 +19,7 @@ import (
 	"github.com/evcc-io/evcc/util"
 	"github.com/evcc-io/evcc/util/locale"
 	"github.com/gorilla/mux"
+	"golang.org/x/text/language"
 )
 
 func indexHandler() http.HandlerFunc {
@@ -75,7 +76,7 @@ func csvResult(ctx context.Context, w http.ResponseWriter, res any) {
 	w.Header().Set("Content-Disposition", `attachment; filename="sessions.csv"`)
 
 	if ww, ok := res.(api.CsvWriter); ok {
-		ww.WriteCsv(ctx, w)
+		_ = ww.WriteCsv(ctx, w)
 	} else {
 		w.WriteHeader(http.StatusInternalServerError)
 	}
@@ -193,8 +194,13 @@ func sessionHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if r.URL.Query().Get("format") == "csv" {
-		accept := r.Header.Get("Accept-Language")
-		ctx := context.WithValue(context.Background(), locale.Locale, accept)
+		// get request language
+		lang := r.Header.Get("Accept-Language")
+		if tags, _, err := language.ParseAcceptLanguage(lang); err == nil && len(tags) > 0 {
+			lang = tags[0].String()
+		}
+
+		ctx := context.WithValue(context.Background(), locale.Locale, lang)
 		csvResult(ctx, w, &res)
 		return
 	}

util/locale/locale.go

@@ -36,9 +36,9 @@ func Init() error {
 		}
 	}
 
-	Language, err := jibber_jabber.DetectLanguage()
+	Language, err = jibber_jabber.DetectLanguage()
 	if err != nil {
-		Language = "de"
+		Language = language.German.String()
 	}
 
 	Localizer = i18n.NewLocalizer(Bundle, Language)