/
i18n.go
439 lines (366 loc) · 11.8 KB
/
i18n.go
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// Package i18n provides internalization and localization features for Iris.
// To use with net/http see https://github.com/kataras/i18n instead.
package i18n
import (
"fmt"
"net/http"
"os"
"strings"
"sync"
"github.com/kataras/iris/v12/context"
"github.com/kataras/iris/v12/core/router"
"golang.org/x/text/language"
)
type (
// Loader accepts a `Matcher` and should return a `Localizer`.
// Functions that implement this type should load locale files.
Loader func(m *Matcher) (Localizer, error)
// Localizer is the interface which returned from a `Loader`.
// Types that implement this interface should be able to retrieve a `Locale`
// based on the language index.
Localizer interface {
// GetLocale should return a valid `Locale` based on the language index.
// It will always match the Loader.Matcher.Languages[index].
// It may return the default language if nothing else matches based on custom localizer's criteria.
GetLocale(index int) context.Locale
}
)
// I18n is the structure which keeps the i18n configuration and implements localization and internationalization features.
type I18n struct {
localizer Localizer
matcher *Matcher
loader Loader
mu sync.Mutex
// ExtractFunc is the type signature for declaring custom logic
// to extract the language tag name.
// Defaults to nil.
ExtractFunc func(ctx context.Context) string
// If not empty, it is language identifier by url query.
//
// Defaults to "lang".
URLParameter string
// If not empty, it is language identifier by cookie of this name.
//
// Defaults to empty.
Cookie string
// If true then a subdomain can be a language identifier.
//
// Defaults to true.
Subdomain bool
// If true then it will return empty string when translation for a a specific language's key was not found.
// Defaults to false, fallback defaultLang:key will be used.
Strict bool
// If true then Iris will wrap its router with the i18n router wrapper on its Build state.
// It will (local) redirect requests like:
// 1. /$lang_prefix/$path to /$path with the language set to $lang_prefix part.
// 2. $lang_subdomain.$domain/$path to $domain/$path with the language set to $lang_subdomain part.
//
// Defaults to true.
PathRedirect bool
}
var _ context.I18nReadOnly = (*I18n)(nil)
// makeTags converts language codes to language Tags.
func makeTags(languages ...string) (tags []language.Tag) {
for _, lang := range languages {
tag, err := language.Parse(lang)
if err == nil && tag != language.Und {
tags = append(tags, tag)
}
}
return
}
// New returns a new `I18n` instance. Use its `Load` or `LoadAssets` to load languages.
func New() *I18n {
return &I18n{
URLParameter: "lang",
Subdomain: true,
PathRedirect: true,
}
}
// Load is a method shortcut to load files using a filepath.Glob pattern.
// It returns a non-nil error on failure.
//
// See `New` and `Glob` package-level functions for more.
func (i *I18n) Load(globPattern string, languages ...string) error {
return i.Reset(Glob(globPattern), languages...)
}
// LoadAssets is a method shortcut to load files using go-bindata.
// It returns a non-nil error on failure.
//
// See `New` and `Asset` package-level functions for more.
func (i *I18n) LoadAssets(assetNames func() []string, asset func(string) ([]byte, error), languages ...string) error {
return i.Reset(Assets(assetNames, asset), languages...)
}
// Reset sets the locales loader and languages.
// It is not meant to be used by users unless
// a custom `Loader` must be used instead of the default one.
func (i *I18n) Reset(loader Loader, languages ...string) error {
tags := makeTags(languages...)
i.loader = loader
i.matcher = &Matcher{
strict: len(tags) > 0,
Languages: tags,
matcher: language.NewMatcher(tags),
}
return i.reload()
}
// reload loads the language files from the provided Loader,
// the `New` package-level function preloads those files already.
func (i *I18n) reload() error { // May be an exported function, if requested.
i.mu.Lock()
defer i.mu.Unlock()
if i.loader == nil {
return fmt.Errorf("nil loader")
}
localizer, err := i.loader(i.matcher)
if err != nil {
return err
}
i.localizer = localizer
return nil
}
// Loaded reports whether `New` or `Load/LoadAssets` called.
func (i *I18n) Loaded() bool {
return i != nil && i.loader != nil && i.localizer != nil && i.matcher != nil
}
// Tags returns the registered languages or dynamically resolved by files.
// Use `Load` or `LoadAssets` first.
func (i *I18n) Tags() []language.Tag {
if !i.Loaded() {
return nil
}
return i.matcher.Languages
}
// SetDefault changes the default language.
// Please avoid using this method; the default behavior will accept
// the first language of the registered tags as the default one.
func (i *I18n) SetDefault(langCode string) bool {
t, err := language.Parse(langCode)
if err != nil {
return false
}
if tag, index, conf := i.matcher.Match(t); conf > language.Low {
if l, ok := i.localizer.(interface {
SetDefault(int) bool
}); ok {
if l.SetDefault(index) {
tags := i.matcher.Languages
// set the order
tags[index] = tags[0]
tags[0] = tag
i.matcher.Languages = tags
i.matcher.matcher = language.NewMatcher(tags)
return true
}
}
}
return false
}
// Matcher implements the languae.Matcher.
// It contains the original language Matcher and keeps an ordered
// list of the registered languages for further use (see `Loader` implementation).
type Matcher struct {
strict bool
Languages []language.Tag
matcher language.Matcher
}
var _ language.Matcher = (*Matcher)(nil)
// Match returns the best match for any of the given tags, along with
// a unique index associated with the returned tag and a confidence
// score.
func (m *Matcher) Match(t ...language.Tag) (language.Tag, int, language.Confidence) {
return m.matcher.Match(t...)
}
// MatchOrAdd acts like Match but it checks and adds a language tag, if not found,
// when the `Matcher.strict` field is true (when no tags are provided by the caller)
// and they should be dynamically added to the list.
func (m *Matcher) MatchOrAdd(t language.Tag) (tag language.Tag, index int, conf language.Confidence) {
tag, index, conf = m.Match(t)
if conf <= language.Low && !m.strict {
// not found, add it now.
m.Languages = append(m.Languages, t)
tag = t
index = len(m.Languages) - 1
conf = language.Exact
m.matcher = language.NewMatcher(m.Languages) // reset matcher to include the new language.
}
return
}
// ParseLanguageFiles returns a map of language indexes and
// their associated files based on the "fileNames".
func (m *Matcher) ParseLanguageFiles(fileNames []string) (map[int][]string, error) {
languageFiles := make(map[int][]string)
for _, fileName := range fileNames {
index := parsePath(m, fileName)
if index == -1 {
continue
}
languageFiles[index] = append(languageFiles[index], fileName)
}
return languageFiles, nil
}
func parsePath(m *Matcher, path string) int {
if t, ok := parseLanguage(path); ok {
if _, index, conf := m.MatchOrAdd(t); conf > language.Low {
return index
}
}
return -1
}
func parseLanguage(path string) (language.Tag, bool) {
if idx := strings.LastIndexByte(path, '.'); idx > 0 {
path = path[0:idx]
}
// path = strings.ReplaceAll(path, "..", "")
names := strings.FieldsFunc(path, func(r rune) bool {
return r == '_' || r == os.PathSeparator || r == '/' || r == '.'
})
for _, s := range names {
t, err := language.Parse(s)
if err != nil {
continue
}
return t, true
}
return language.Und, false
}
// TryMatchString will try to match the "s" with a registered language tag.
// It returns -1 as the language index and false if not found.
func (i *I18n) TryMatchString(s string) (language.Tag, int, bool) {
if tag, err := language.Parse(s); err == nil {
if tag, index, conf := i.matcher.Match(tag); conf > language.Low {
return tag, index, true
}
}
return language.Und, -1, false
}
// Tr returns a translated message based on the "lang" language code
// and its key(format) with any optional arguments attached to it.
//
// It returns an empty string if "format" not matched.
func (i *I18n) Tr(lang, format string, args ...interface{}) string {
_, index, ok := i.TryMatchString(lang)
if !ok {
index = 0
}
loc := i.localizer.GetLocale(index)
if loc != nil {
msg := loc.GetMessage(format, args...)
if msg == "" && !i.Strict && index > 0 {
// it's not the default/fallback language and not message found for that lang:key.
return i.localizer.GetLocale(0).GetMessage(format, args...)
}
return msg
}
return fmt.Sprintf(format, args...)
}
const acceptLanguageHeaderKey = "Accept-Language"
// GetLocale returns the found locale of a request.
// It will return the first registered language if nothing else matched.
func (i *I18n) GetLocale(ctx context.Context) context.Locale {
// if v := ctx.Values().Get(ctx.Application().ConfigurationReadOnly().GetLocaleContextKey()); v != nil {
// if locale, ok := v.(context.Locale); ok {
// return locale
// }
// }
var (
index int
ok bool
)
if !ok && i.ExtractFunc != nil {
if v := i.ExtractFunc(ctx); v != "" {
_, index, ok = i.TryMatchString(v)
}
}
if !ok && i.URLParameter != "" {
if v := ctx.URLParam(i.URLParameter); v != "" {
_, index, ok = i.TryMatchString(v)
}
}
if !ok && i.Cookie != "" {
if v := ctx.GetCookie(i.Cookie); v != "" {
_, index, ok = i.TryMatchString(v) // url.QueryUnescape(cookie.Value)
}
}
if !ok && i.Subdomain {
if v := ctx.Subdomain(); v != "" {
_, index, ok = i.TryMatchString(v)
}
}
if !ok {
if v := ctx.GetHeader(acceptLanguageHeaderKey); v != "" {
desired, _, err := language.ParseAcceptLanguage(v)
if err == nil {
if _, idx, conf := i.matcher.Match(desired...); conf > language.Low {
index = idx
}
}
}
}
// locale := i.localizer.GetLocale(index)
// ctx.Values().Set(ctx.Application().ConfigurationReadOnly().GetLocaleContextKey(), locale)
// // if 0 then it defaults to the first language.
// return locale
locale := i.localizer.GetLocale(index)
if locale == nil {
return nil
}
return locale
}
// GetMessage returns the localized text message for this "r" request based on the key "format".
func (i *I18n) GetMessage(ctx context.Context, format string, args ...interface{}) string {
loc := i.GetLocale(ctx)
if loc != nil {
// it's not the default/fallback language and not message found for that lang:key.
msg := loc.GetMessage(format, args...)
if msg == "" && !i.Strict && loc.Index() > 0 {
return i.localizer.GetLocale(0).GetMessage(format, args...)
}
}
return fmt.Sprintf(format, args...)
}
// Wrapper returns a new router wrapper.
// The result function can be passed on `Application.WrapRouter`.
// It compares the path prefix for translated language and
// local redirects the requested path with the selected (from the path) language to the router.
//
// You do NOT have to call it manually, just set the `I18n.PathRedirect` field to true.
func (i *I18n) Wrapper() router.WrapperFunc {
if !i.PathRedirect {
return nil
}
return func(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
found := false
path := r.URL.Path[1:]
if idx := strings.IndexByte(path, '/'); idx > 0 {
path = path[:idx]
}
if path != "" {
if tag, _, ok := i.TryMatchString(path); ok {
lang := tag.String()
path = r.URL.Path[len(path)+1:]
if path == "" {
path = "/"
}
r.RequestURI = path
r.URL.Path = path
r.Header.Set(acceptLanguageHeaderKey, lang)
found = true
}
}
if !found && i.Subdomain {
host := context.GetHost(r)
if dotIdx := strings.IndexByte(host, '.'); dotIdx > 0 {
if subdomain := host[0:dotIdx]; subdomain != "" {
if tag, _, ok := i.TryMatchString(subdomain); ok {
host = host[dotIdx+1:]
r.URL.Host = host
r.Host = host
r.Header.Set(acceptLanguageHeaderKey, tag.String())
}
}
}
}
next(w, r)
}
}