i18n

i18n - translations module for Go

i18n is a set of functions to help with project translations and language detection.

Usage

First get the module:

go get go.deck17.com/i18n

Import the the module in the final project:

import (
    "go.deck17.com/i18n"
    "go.deck17.com/i18n/detect"
)

Translate text

i18n exports a single constructor that accepts a map[string]map[string]string with language and translations maps. As a result it returns two funcs, each accepting language code as a string, key to translate and optional arguments for string substitution (as formatted by fmt.Sprintf). The returned functions are defined as:

func(string, string, args ...any) string
func(string, string, args ...any) error

Initialize translator

This is an example how to initialize the translator:

var translations = map[string]map[string]string{
    "en": {
        "hello": "Hello World!",
    },
    "de": {
        "hello": "Hallo, Welt!",
    },
}

// in this case "en" is the default language
var T, Terr = i18n.NewTranslator(translations, "en")

Use translator in the code

Translate text inside Go code:

fmt.Printf("Translated text (en): %s\n", T("en", "hello"))
fmt.Printf("Translated text (de): %s\n", T("de", "hello"))

Translated error messages

Similarly, Terr can be used to generate localized error messages instead of strings:

func do_stuff() error {
    return Terr("en", "hello")
}

Detecting language in http server applications

The i18n/detect module contains a function that can be used to detect currently selected web language. It uses query string and cookies to do so and automatically sends / updates cookie when language is changed (with query parameter).

// the first language in the list is used as a default language
var detectLanguage = detect.NewHttpDetector(
    []string{"en", "de"}, // list of languages
    "/",                  // cookie path
    31536000,             // max age in seconds
}

The result function detectLanguage accepts http.ResponseWriter and *http.Request arguments and returns string with language code.