/
translator.go
275 lines (235 loc) · 6.48 KB
/
translator.go
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package astikit
import (
"context"
"encoding/json"
"fmt"
"net/http"
"os"
"path/filepath"
"sort"
"strconv"
"strings"
"sync"
)
// Translator represents an object capable of translating stuff
type Translator struct {
defaultLanguage string
m *sync.RWMutex // Lock p
p map[string]string
validLanguages map[string]bool
}
// TranslatorOptions represents Translator options
type TranslatorOptions struct {
DefaultLanguage string
ValidLanguages []string
}
// NewTranslator creates a new Translator
func NewTranslator(o TranslatorOptions) (t *Translator) {
t = &Translator{
defaultLanguage: o.DefaultLanguage,
m: &sync.RWMutex{},
p: make(map[string]string),
validLanguages: make(map[string]bool),
}
for _, l := range o.ValidLanguages {
t.validLanguages[l] = true
}
return
}
// ParseDir adds translations located in ".json" files in the specified dir
// If ".json" files are located in child dirs, keys will be prefixed with their paths
func (t *Translator) ParseDir(dirPath string) (err error) {
// Default dir path
if dirPath == "" {
if dirPath, err = os.Getwd(); err != nil {
err = fmt.Errorf("astikit: getwd failed: %w", err)
return
}
}
// Make sure to clean dir path so that we get consistent path separator with filepath.Walk
dirPath = filepath.Clean(dirPath)
// Walk through dir
if err = filepath.Walk(dirPath, func(path string, info os.FileInfo, e error) (err error) {
// Check input error
if e != nil {
err = fmt.Errorf("astikit: walking %s has an input error for path %s: %w", dirPath, path, e)
return
}
// Only process files
if info.IsDir() {
return
}
// Only process ".json" files
if filepath.Ext(path) != ".json" {
return
}
// Parse file
if err = t.ParseFile(dirPath, path); err != nil {
err = fmt.Errorf("astikit: parsing %s failed: %w", path, err)
return
}
return
}); err != nil {
err = fmt.Errorf("astikit: walking %s failed: %w", dirPath, err)
return
}
return
}
// ParseFile adds translation located in the provided path
func (t *Translator) ParseFile(dirPath, path string) (err error) {
// Lock
t.m.Lock()
defer t.m.Unlock()
// Open file
var f *os.File
if f, err = os.Open(path); err != nil {
err = fmt.Errorf("astikit: opening %s failed: %w", path, err)
return
}
defer f.Close()
// Unmarshal
var p map[string]interface{}
if err = json.NewDecoder(f).Decode(&p); err != nil {
err = fmt.Errorf("astikit: unmarshaling %s failed: %w", path, err)
return
}
// Get language
language := strings.TrimSuffix(filepath.Base(path), filepath.Ext(path))
// Update valid languages
t.validLanguages[language] = true
// Get prefix
prefix := language
if dp := filepath.Dir(path); dp != dirPath {
var fs []string
for _, v := range strings.Split(strings.TrimPrefix(dp, dirPath), string(os.PathSeparator)) {
if v != "" {
fs = append(fs, v)
}
}
prefix += "." + strings.Join(fs, ".")
}
// Parse
t.parse(p, prefix)
return
}
func (t *Translator) key(prefix, key string) string {
return prefix + "." + key
}
func (t *Translator) parse(i map[string]interface{}, prefix string) {
for k, v := range i {
p := t.key(prefix, k)
switch a := v.(type) {
case string:
t.p[p] = a
case map[string]interface{}:
t.parse(a, p)
}
}
}
// HTTPMiddleware is the Translator HTTP middleware
func (t *Translator) HTTPMiddleware(h http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
// Store language in context
if l := r.Header.Get("Accept-Language"); l != "" {
*r = *r.WithContext(contextWithTranslatorLanguage(r.Context(), t.parseAcceptLanguage(l)))
}
// Next handler
h.ServeHTTP(rw, r)
})
}
func (t *Translator) parseAcceptLanguage(h string) string {
// Split on comma
var qs []float64
ls := make(map[float64][]string)
for _, c := range strings.Split(strings.TrimSpace(h), ",") {
// Empty
c = strings.TrimSpace(c)
if c == "" {
continue
}
// Split on semi colon
ss := strings.Split(c, ";")
// Parse coefficient
q := float64(1)
if len(ss) > 1 {
s := strings.TrimSpace(ss[1])
if strings.HasPrefix(s, "q=") {
var err error
if q, err = strconv.ParseFloat(strings.TrimPrefix(s, "q="), 64); err != nil {
q = 1
}
}
}
// Add
if _, ok := ls[q]; !ok {
qs = append(qs, q)
}
ls[q] = append(ls[q], strings.TrimSpace(ss[0]))
}
// Order coefficients
sort.Float64s(qs)
// Loop through coefficients in reverse order
for idx := len(qs) - 1; idx >= 0; idx-- {
for _, l := range ls[qs[idx]] {
if _, ok := t.validLanguages[l]; ok {
return l
}
}
}
return ""
}
const contextKeyTranslatorLanguage = contextKey("astikit.translator.language")
type contextKey string
func contextWithTranslatorLanguage(ctx context.Context, language string) context.Context {
return context.WithValue(ctx, contextKeyTranslatorLanguage, language)
}
func translatorLanguageFromContext(ctx context.Context) string {
v, ok := ctx.Value(contextKeyTranslatorLanguage).(string)
if !ok {
return ""
}
return v
}
func (t *Translator) language(language string) string {
if language == "" {
return t.defaultLanguage
}
return language
}
// LanguageCtx returns the translator language from the context, or the default language if not in the context
func (t *Translator) LanguageCtx(ctx context.Context) string {
return t.language(translatorLanguageFromContext(ctx))
}
// Translate translates a key into a specific language
func (t *Translator) Translate(language, key string) string {
// Lock
t.m.RLock()
defer t.m.RUnlock()
// Get translation
k1 := t.key(t.language(language), key)
v, ok := t.p[k1]
if ok {
return v
}
// Default translation
k2 := t.key(t.defaultLanguage, key)
if v, ok = t.p[k2]; ok {
return v
}
return k1
}
// Translatef translates a key into a specific language with optional formatting args
func (t *Translator) Translatef(language, key string, args ...interface{}) string {
return fmt.Sprintf(t.Translate(language, key), args...)
}
// TranslateCtx is an alias for TranslateC
func (t *Translator) TranslateCtx(ctx context.Context, key string) string {
return t.TranslateC(ctx, key)
}
// TranslateC translates a key using the language specified in the context
func (t *Translator) TranslateC(ctx context.Context, key string) string {
return t.Translate(translatorLanguageFromContext(ctx), key)
}
func (t *Translator) TranslateCf(ctx context.Context, key string, args ...interface{}) string {
return t.Translatef(translatorLanguageFromContext(ctx), key, args...)
}