Handle multi-lang request for external translation

Frontend/client lib (i18next) sends request for multiple
languages at the same time (format: en+sl+de).

Some internal changes on ext. translation loading (storing) were needed.

pkg/locale/load.go

@@ -178,20 +178,14 @@ func loadTranslations(lang *Language) (err error) {
 		return
 	}
 
-	// wraps JSON with namespaces under each app with a language tag:
-	// { <lang>: { namespace ..., namespace ... } }
-	//
-	// This simplifies and unifies the output and makes it compatible
-	// with the frontend libs
+	// encode all external (for webapps, clientS) translations
+	// into buffers that will be copied directly into responses
 	for app, nss := range auxExternal {
 		var (
 			buf = &bytes.Buffer{}
-			aux = make(map[string]interface{})
 		)
 
-		aux[lang.Tag.String()] = nss
-
-		if err = json.NewEncoder(buf).Encode(aux); err != nil {
+		if err = json.NewEncoder(buf).Encode(nss); err != nil {
 			return
 		}
 		lang.external[app] = bytes.NewReader(buf.Bytes())

pkg/locale/service.go

@@ -64,7 +64,7 @@ func Service(log *zap.Logger, opt options.LocaleOpt) (*service, error) {
 		lang = strings.TrimSpace(lang)
 		tag := language.Make(lang)
 		if tag.IsRoot() {
-			return nil, fmt.Errorf("failed to parse language '%s'", lang)
+			return nil, fmt.Errorf("failed to parse language '%s' (did you use comma to separate them?)", lang)
 		}
 
 		svc.tags = append(svc.tags, tag)
@@ -220,16 +220,23 @@ func (svc *service) HasApplication(lang language.Tag, app string) bool {
 }
 
 // EncodeExternal writes into
-func (svc *service) EncodeExternal(w io.Writer, lang language.Tag, app string) (err error) {
+func (svc *service) EncodeExternal(w io.Writer, app string, ll ...language.Tag) (err error) {
 	svc.l.RLock()
 	defer svc.l.RUnlock()
 
-	if svc.HasApplication(lang, app) {
-		svc.set[lang].external[app].Seek(0, 0)
-		_, err = io.Copy(w, svc.set[lang].external[app])
-	} else {
-		err = fmt.Errorf("application or language missing")
+	fmt.Fprint(w, "{")
+	for i, lang := range ll {
+		if i > 0 {
+			fmt.Fprint(w, ",")
+		}
+
+		if svc.HasApplication(lang, app) {
+			fmt.Fprintf(w, "%q:", lang)
+			svc.set[lang].external[app].Seek(0, 0)
+			_, _ = io.Copy(w, svc.set[lang].external[app])
+		}
 	}
+	fmt.Fprint(w, "}")
 
 	return err
 }

system/rest/locales.go

@@ -3,6 +3,7 @@ package rest
 import (
 	"context"
 	"net/http"
+	"strings"
 
 	"github.com/cortezaproject/corteza-server/pkg/errors"
 	"github.com/cortezaproject/corteza-server/pkg/locale"
@@ -46,31 +47,52 @@ func (ctrl Locale) List(ctx context.Context, r *request.LocaleList) (interface{}
 func (ctrl Locale) Get(ctx context.Context, r *request.LocaleGet) (interface{}, error) {
 	svc := locale.Global()
 
+	// We're using + as a language delimiter
+	// because webapp client i18n lib does this by default
+	// (url encoded space becomes a +)
+	const langSplit = "+"
+
 	return func(w http.ResponseWriter, req *http.Request) {
-		if !svc.HasLanguage(language.Make(r.Lang)) {
-			// @todo temp workaround until frontend knows what languages it can use
-			r.Lang = svc.List()[0].Tag.String()
-		}
-
-		if !svc.HasLanguage(language.Make(r.Lang)) {
+		if len(svc.List()) == 0 {
 			errors.ProperlyServeHTTP(w, req, errors.New(
 				errors.KindNotFound,
-				"no such language",
+				"no languages found",
 				errors.StackTrimAtFn("http.HandlerFunc.ServeHTTP"),
 			), true)
 			return
 		}
 
-		if !svc.HasApplication(language.Make(r.Lang), r.Application) {
-			errors.ProperlyServeHTTP(w, req, errors.New(
-				errors.KindNotFound,
-				"no such application",
-				errors.StackTrimAtFn("http.HandlerFunc.ServeHTTP"),
-			), true)
-			return
+		// default to 1st language
+		//var def = svc.List()[0].Tag
+		var ll = []language.Tag{}
+
+		for _, candidate := range strings.Split(r.Lang, langSplit) {
+			ll = append(ll, language.Make(candidate))
+			//if svc.HasLanguage(tmp) {
+			//	ll = append(ll, lang)
+			//	break
+			//}
 		}
 
-		if err := locale.Global().EncodeExternal(w, language.Make(r.Lang), r.Application); err != nil {
+		//if !svc.HasLanguage(lang) {
+		//	errors.ProperlyServeHTTP(w, req, errors.New(
+		//		errors.KindNotFound,
+		//		"no such language",
+		//		errors.StackTrimAtFn("http.HandlerFunc.ServeHTTP"),
+		//	), true)
+		//	return
+		//}
+
+		//if !svc.HasApplication(lang, r.Application) {
+		//	errors.ProperlyServeHTTP(w, req, errors.New(
+		//		errors.KindNotFound,
+		//		"no such application",
+		//		errors.StackTrimAtFn("http.HandlerFunc.ServeHTTP"),
+		//	), true)
+		//	return
+		//}
+
+		if err := locale.Global().EncodeExternal(w, r.Application, ll...); err != nil {
 			errors.ProperlyServeHTTP(w, req, err, true)
 		}