1 files changed, 97 insertions, 0 deletions
diff --git a/cmd/site/locale.go b/cmd/site/locale.go
new file mode 100644
index 0000000..a65034a
--- /dev/null
+++ b/cmd/site/locale.go
@@ -0,0 +1,97 @@
+package main
+
+import (
+	"errors"
+	"net/http"
+	"strconv"
+	"strings"
+)
+
+// Locale is locale value from the Accept-Language header in request
+type Locale struct {
+	Lang, Country string
+	Qual          float64
+}
+
+// Name returns the locale value in 'lang' or 'lang_country' format
+// eg: de_DE, en_US, gb
+func (l *Locale) Name() string {
+	if len(l.Country) > 0 {
+		return l.Lang + "_" + l.Country
+	}
+	return l.Lang
+}
+
+// ParseLocale creates a Locale from a locale string
+func ParseLocale(locale string) Locale {
+	locsplt := strings.Split(locale, "_")
+	resp := Locale{}
+	resp.Lang = locsplt[0]
+	if len(locsplt) > 1 {
+		resp.Country = locsplt[1]
+	}
+	return resp
+}
+
+const (
+	acceptLanguage = "Accept-Language"
+)
+
+func supportedLocales(alstr string) []Locale {
+	locales := make([]Locale, 0)
+	alstr = strings.Replace(alstr, " ", "", -1)
+	if alstr == "" {
+		return locales
+	}
+	al := strings.Split(alstr, ",")
+	for _, lstr := range al {
+		locales = append(locales, Locale{
+			Lang:    parseLang(lstr),
+			Country: parseCountry(lstr),
+			Qual:    parseQual(lstr),
+		})
+	}
+	return locales
+}
+
+// GetLocales returns supported locales for the given requet
+func GetLocales(r *http.Request) []Locale {
+	return supportedLocales(r.Header.Get(acceptLanguage))
+}
+
+// GetPreferredLocale return preferred locale for the given reuqest
+// returns error if there is no preferred locale
+func GetPreferredLocale(r *http.Request) (*Locale, error) {
+	locales := GetLocales(r)
+	if len(locales) == 0 {
+		return &Locale{}, errors.New("No locale found")
+	}
+	return &locales[0], nil
+}
+
+func parseLang(val string) string {
+	locale := strings.Split(val, ";")[0]
+	lang := strings.Split(locale, "-")[0]
+	return lang
+}
+
+func parseCountry(val string) string {
+	locale := strings.Split(val, ";")[0]
+	spl := strings.Split(locale, "-")
+	if len(spl) > 1 {
+		return spl[1]
+	}
+	return ""
+}
+
+func parseQual(val string) float64 {
+	spl := strings.Split(val, ";")
+	if len(spl) > 1 {
+		qual, err := strconv.ParseFloat(strings.Split(spl[1], "=")[1], 64)
+		if err != nil {
+			return 1
+		}
+		return qual
+	}
+	return 1
+}