Make website show localised text

localisation.go

@@ -1,16 +1,23 @@
 package main
 
 import (
-	"fmt"
-
 	"github.com/gin-gonic/gin"
+	"zxq.co/ripple/hanayo/modules/locale"
 )
 
 // T translates a string into the language specified by the request.
 func T(c *gin.Context, s string, args ...interface{}) string {
-	return fmt.Sprintf(s, args...)
+	return locale.Get(getLang(c), s, args...)
 }
 
 func (b *baseTemplateData) T(s string, args ...interface{}) string {
 	return T(b.Gin, s, args...)
 }
+
+func getLang(c *gin.Context) []string {
+	s, _ := c.Cookie("language")
+	if s != "" {
+		return []string{s}
+	}
+	return locale.ParseHeader(c.Request.Header.Get("Accept-Language"))
+}

modules/locale/lang_map.go

@@ -0,0 +1,46 @@
+package locale
+
+import (
+	"fmt"
+	"io/ioutil"
+	"strings"
+
+	"github.com/leonelquinteros/gotext"
+)
+
+var languageMap = make(map[string]*gotext.Po, 20)
+
+func loadLanguages() {
+	files, err := ioutil.ReadDir("./data/locales")
+	if err != nil {
+		fmt.Println("loadLanguages", err)
+		return
+	}
+	for _, file := range files {
+		if file.Name() == "templates.pot" || file.Name() == "." || file.Name() == ".." {
+			continue
+		}
+
+		po := new(gotext.Po)
+		po.ParseFile("./data/locales/" + file.Name())
+
+		langName := strings.TrimPrefix(strings.TrimSuffix(file.Name(), ".po"), "templates-")
+		languageMap[langName] = po
+	}
+}
+
+func init() {
+	loadLanguages()
+}
+
+// Get retrieves a string from a language
+func Get(langs []string, str string, vars ...interface{}) string {
+	for _, lang := range langs {
+		l := languageMap[lang]
+		if l != nil {
+			return l.Get(str, vars...)
+		}
+	}
+
+	return fmt.Sprintf(str, vars...)
+}

modules/locale/parse_header.go

@@ -0,0 +1,38 @@
+package locale
+
+import (
+	"sort"
+	"strconv"
+	"strings"
+)
+
+// ParseHeader parses an Accept-Language header, and sorts the values.
+func ParseHeader(header string) []string {
+	if header == "" {
+		return nil
+	}
+	parts := strings.Split(header, ",")
+
+	sort.Slice(parts, func(i, j int) bool {
+		return getQuality(parts[i]) > getQuality(parts[j])
+	})
+
+	for idx, val := range parts {
+		parts[idx] = strings.Replace(strings.SplitN(val, ";q=", 2)[0], "-", "_", 1)
+	}
+
+	return parts
+}
+
+func getQuality(s string) float32 {
+	idx := strings.Index(s, ";q=")
+	if idx == -1 {
+		return 1
+	}
+
+	f, err := strconv.ParseFloat(s[idx+3:], 32)
+	if err != nil {
+		return 1
+	}
+	return float32(f)
+}

modules/locale/parse_header_test.go

@@ -0,0 +1,45 @@
+package locale
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParseHeader(t *testing.T) {
+	tt := []struct {
+		In  string
+		Out []string
+	}{
+		{
+			"en",
+			[]string{"en"},
+		},
+		{
+			"en-GB",
+			[]string{"en_GB"},
+		},
+		{
+			"en-GB;q=0.5,it",
+			[]string{"it", "en_GB"},
+		},
+		{
+			"en-GB;q=0.5,it,pl;q=0.2",
+			[]string{"it", "en_GB", "pl"},
+		},
+		{
+			"en-GB;q=0.5,pl;q=xd",
+			[]string{"pl", "en_GB"},
+		},
+		{
+			"",
+			nil,
+		},
+	}
+
+	for _, el := range tt {
+		got := ParseHeader(el.In)
+		if !reflect.DeepEqual(got, el.Out) {
+			t.Errorf("got %v want %v", got, el.Out)
+		}
+	}
+}