init

.gitignore

@@ -0,0 +1 @@
+.vscode

example_translations/de.json

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+{
+  "KEY": "WERT",
+  "WITH_PARAM": "WERT %[1]s_%[2]s"
+}

example_translations/en.json

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+{
+  "KEY": "VALUE",
+  "WITH_PARAM": "VALUE %[1]s_%[2]s"
+}

example_translations/files.go

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+package exampletranslations
+
+import "embed"
+
+//go:embed *.json
+var Files embed.FS

example_translations/fr.json

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+{
+  "KEY": "VALEUR",
+  "WITH_PARAM": "VALEUR %[1]s_%[2]s"
+}

go.mod

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+module git.apihub24.de/admin/translation
+
+go 1.22.0

translation.go

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+package translation
+
+import (
+	"embed"
+	"encoding/json"
+	"fmt"
+	"strings"
+)
+
+var defaultCulture = "en"
+var sources = make(map[string]map[string]string)
+var translationFiles embed.FS
+
+func SetDefaultCulture(culture string) {
+	defaultCulture = strings.ToLower(culture)
+}
+
+func Init(files embed.FS) {
+	translationFiles = files
+}
+
+func Get(key string, culture string, args ...string) string {
+	source, err := loadSource(culture)
+	if err != nil {
+		return fmt.Sprintf("unknown error: %s", err.Error())
+	}
+	value, ok := source[key]
+	if !ok {
+		return fmt.Sprintf("no value for key %s found in source %s", key, culture)
+	}
+	if len(args) > 0 {
+		var tmpArgs = make([]any, len(args))
+		for idx, arg := range args {
+			tmpArgs[idx] = arg
+		}
+		return fmt.Sprintf(value, tmpArgs...)
+	}
+	return value
+}
+
+func loadSource(culture string) (map[string]string, error) {
+	source, ok := sources[culture]
+	if ok {
+		return source, nil
+	}
+	data, err := translationFiles.ReadFile(fmt.Sprintf("%s.json", strings.ToLower(culture)))
+	if err != nil {
+		data, err = translationFiles.ReadFile(fmt.Sprintf("%s.json", defaultCulture))
+		if err != nil {
+			return source, fmt.Errorf("can not load translation source for culture %s DefaultCulture: %s", culture, defaultCulture)
+		}
+	}
+	err = json.Unmarshal(data, &source)
+	if err != nil {
+		return source, fmt.Errorf("can not parse translation source %s", culture)
+	}
+	sources[culture] = source
+	return sources[culture], nil
+}

translation_test.go

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+package translation_test
+
+import (
+	"testing"
+
+	"git.apihub24.de/admin/translation"
+	exampletranslations "git.apihub24.de/admin/translation/example_translations"
+)
+
+func Test_Translation_Init(t *testing.T) {
+	translation.Init(exampletranslations.Files)
+	if translation.Get("KEY", "de") != "WERT" {
+		t.Errorf("translations not initialized!")
+	}
+}
+
+func Test_Translation_Get_de(t *testing.T) {
+	translation.Init(exampletranslations.Files)
+	value := translation.Get("KEY", "de")
+	if value != "WERT" {
+		t.Errorf("expect German KEY to have Value 'WERT' but was %s", value)
+	}
+}
+
+func Test_Translation_Get_en(t *testing.T) {
+	translation.Init(exampletranslations.Files)
+	value := translation.Get("KEY", "en")
+	if value != "VALUE" {
+		t.Errorf("expect English KEY to have Value 'VALUE' but was %s", value)
+	}
+}
+
+func Test_Translation_Get_fr(t *testing.T) {
+	translation.Init(exampletranslations.Files)
+	value := translation.Get("KEY", "fr")
+	if value != "VALEUR" {
+		t.Errorf("expect France KEY to have Value 'VALEUR' but was %s", value)
+	}
+}
+
+func Test_Translation_Get_Fallback_en(t *testing.T) {
+	translation.Init(exampletranslations.Files)
+	value := translation.Get("KEY", "notexists")
+	if value != "VALUE" {
+		t.Errorf("expect Fallback KEY to have Value 'VALUE' but was %s", value)
+	}
+}
+
+func Test_Translation_Can_Change_Fallback_Language(t *testing.T) {
+	translation.Init(exampletranslations.Files)
+	translation.SetDefaultCulture("de")
+	value := translation.Get("KEY", "notexists")
+	if value != "WERT" {
+		t.Errorf("expect Fallback KEY to have Value 'WERT' but was %s", value)
+	}
+}
+
+func Test_Translation_Get_With_Parameter(t *testing.T) {
+	translation.Init(exampletranslations.Files)
+	valueDe := translation.Get("WITH_PARAM", "de", "a", "b")
+	valueEn := translation.Get("WITH_PARAM", "en", "a", "b")
+	valueFr := translation.Get("WITH_PARAM", "fr", "a", "b")
+	if valueDe != "WERT a_b" {
+		t.Errorf("expect German KEY to have Value 'WERT a_b' but was %s", valueDe)
+	}
+	if valueEn != "VALUE a_b" {
+		t.Errorf("expect English KEY to have Value 'VALUE a_b' but was %s", valueEn)
+	}
+	if valueFr != "VALEUR a_b" {
+		t.Errorf("expect France KEY to have Value 'VALEUR a_b' but was %s", valueFr)
+	}
+}