package languages import ( "fmt" "github.com/nicksnyder/go-i18n/i18n" "html/template" "net/http" ) // When go-i18n finds a language with >0 translations, it uses it as the Tfunc // However, if said language has a missing translation, it won't fallback to the "main" language func TfuncWithFallback(language string, languages ...string) (i18n.TranslateFunc, error) { // Use the last language on the args as the fallback one. fallbackLanguage := language if languages != nil { fallbackLanguage = languages[len(languages)-1] } T, err1 := i18n.Tfunc(language, languages...) fallbackT, err2 := i18n.Tfunc(fallbackLanguage) if err1 != nil && err2 != nil { // fallbackT is still a valid function even with the error, it returns translationID. return fallbackT, err2; } return func(translationID string, args ...interface{}) string { if translated := T(translationID, args...); translated != translationID { return translated } return fallbackT(translationID, args...) }, nil } func SetTranslation(tmpl *template.Template, language string, languages ...string) i18n.TranslateFunc { T, _ := TfuncWithFallback(language, languages...) tmpl.Funcs(map[string]interface{}{ "T": func(str string, args ...interface{}) template.HTML { return template.HTML(fmt.Sprintf(T(str), args...)) }, }) return T } func SetTranslationFromRequest(tmpl *template.Template, r *http.Request, defaultLanguage string) i18n.TranslateFunc { cookie, err := r.Cookie("lang") cookieLanguage := "" if err == nil { cookieLanguage = cookie.Value } // go-i18n supports the format of the Accept-Language header, thankfully. headerLanguage := r.Header.Get("Accept-Language") return SetTranslation(tmpl, cookieLanguage, headerLanguage, defaultLanguage) }