add tests for #1369 and various improvements

Former-commit-id: 2fe1f077cf5b6a0fb32a27cf86462fea776a7d58

_examples/miscellaneous/i18n/main.go

@@ -5,25 +5,29 @@ import (
 	"github.com/kataras/iris/v12/middleware/i18n"
 )
 
-func newApp() *iris.Application {
-	app := iris.New()
-	app.Logger().SetLevel("debug")
-
-	i18nConfig := i18n.Config{
+var i18nConfig = i18n.Config{
 	Default:       "en-US",
-		URLParameter:  "lang",
-		PathParameter: "lang",
+	URLParameter:  "lang", // optional.
+	PathParameter: "lang", // optional.
 	Languages: map[string]string{
-			"en-US": "./locales/locale_en-US.ini",
-			"el-GR": "./locales/locale_el-GR.ini",
-			"zh-CN": "./locales/locale_zh-CN.ini",
+		"en-US": "./locales/locale_en-US.ini", // maps to en-US, en-us and en.
+		"el-GR": "./locales/locale_el-GR.ini", // maps to el-GR, el-gr and el.
+		"zh-CN": "./locales/locale_zh-CN.ini", // maps to zh-CN, zh-cn and zh.
+	},
+	Alternatives: map[string]string{ // optional.
+		"english": "en-US", // now english maps to en-US
+		"greek":   "el-GR", // and greek to el-GR
+		"chinese": "zh-CN", // and chinese to zh-CN too.
 	},
-		Alternatives: map[string]string{"greek": "el-GR"},
 }
 
+func newApp() *iris.Application {
+	app := iris.New()
+
 	// See https://github.com/kataras/iris/issues/1369
-	// if you want to enable this (SEO) feature.
-	app.WrapRouter(i18n.NewWrapper(i18nConfig))
+	// if you want to enable this (SEO) feature (OPTIONAL).
+	i18nWrapper := i18n.NewWrapper(i18nConfig)
+	app.WrapRouter(i18nWrapper)
 
 	i18nMiddleware := i18n.New(i18nConfig)
 	app.Use(i18nMiddleware)
@@ -37,12 +41,10 @@ func newApp() *iris.Application {
 		// it tries to find the language by the "language" cookie
 		// if didn't found then it it set to the Default set on the configuration
 
-		// hi is the key, 'iris' is the %s on the .ini file
+		// hi is the key/word, 'iris' is the %s on the .ini file
 		// the second parameter is optional
 
-		// hi := ctx.Translate("hi", "iris")
-		// or:
-		hi := i18n.Translate(ctx, "hi", "iris")
+		hi := ctx.Translate("hi", "iris")
 
 		// GetTranslateLanguageContextKey() == "language"
 		language := ctx.Values().GetString(ctx.Application().ConfigurationReadOnly().GetTranslateLanguageContextKey())
@@ -61,6 +63,9 @@ func newApp() *iris.Application {
 		ctx.WriteString("sitemap")
 	})
 
+	// Note: It is highly recommended to use one and no more i18n middleware instances at a time,
+	// the first one was already passed by `app.Use` above.
+	// This middleware which registers on "/multi" route is here just for the shake of the example.
 	multiLocale := i18n.New(i18n.Config{
 		Default:      "en-US",
 		URLParameter: "lang",
@@ -73,8 +78,8 @@ func newApp() *iris.Application {
 	app.Get("/multi", multiLocale, func(ctx iris.Context) {
 		language := ctx.Values().GetString(ctx.Application().ConfigurationReadOnly().GetTranslateLanguageContextKey())
 
-		fromFirstFileValue := i18n.Translate(ctx, "key1")
-		fromSecondFileValue := i18n.Translate(ctx, "key2")
+		fromFirstFileValue := ctx.Translate("key1")
+		fromSecondFileValue := ctx.Translate("key2")
 		ctx.Writef("From the language: %s, translated output:\n%s=%s\n%s=%s",
 			language, "key1", fromFirstFileValue,
 			"key2", fromSecondFileValue)

_examples/miscellaneous/i18n/main_test.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"strings"
 	"testing"
 
 	"github.com/kataras/iris/v12/httptest"
@@ -12,9 +13,11 @@ func TestI18n(t *testing.T) {
 
 	expectedf := "From the language %s translated output: %s"
 	var (
-		elgr = fmt.Sprintf(expectedf, "el-GR", "γεια, iris")
-		enus = fmt.Sprintf(expectedf, "en-US", "hello, iris")
-		zhcn = fmt.Sprintf(expectedf, "zh-CN", "您好，iris")
+		tests = map[string]string{
+			"en-US": fmt.Sprintf(expectedf, "en-US", "hello, iris"),
+			"el-GR": fmt.Sprintf(expectedf, "el-GR", "γεια, iris"),
+			"zh-CN": fmt.Sprintf(expectedf, "zh-CN", "您好，iris"),
+		}
 
 		elgrMulti = fmt.Sprintf("From the language: %s, translated output:\n%s=%s\n%s=%s", "el-GR",
 			"key1",
@@ -29,20 +32,43 @@ func TestI18n(t *testing.T) {
 	)
 
 	e := httptest.New(t, app)
-	// default is en-US
-	e.GET("/").Expect().Status(httptest.StatusOK).Body().Equal(enus)
-	// default is en-US if lang query unable to be found
-	e.GET("/").Expect().Status(httptest.StatusOK).Body().Equal(enus)
+	// default should be en-US.
+	e.GET("/").Expect().Status(httptest.StatusOK).Body().Equal(tests["en-US"])
 
-	e.GET("/").WithQueryString("lang=el-GR").Expect().Status(httptest.StatusOK).
-		Body().Equal(elgr)
-	e.GET("/").WithQueryString("lang=en-US").Expect().Status(httptest.StatusOK).
-		Body().Equal(enus)
-	e.GET("/").WithQueryString("lang=zh-CN").Expect().Status(httptest.StatusOK).
-		Body().Equal(zhcn)
+	for lang, body := range tests {
+		e.GET("/").WithQueryString("lang=" + lang).Expect().Status(httptest.StatusOK).
+			Body().Equal(body)
+
+		// test lowercase.
+		e.GET("/").WithQueryString("lang=" + strings.ToLower(lang)).Expect().Status(httptest.StatusOK).
+			Body().Equal(body)
+
+		// test first part (e.g. en instead of en-US).
+		langFirstPart := strings.Split(lang, "-")[0]
+		e.GET("/").WithQueryString("lang=" + langFirstPart).Expect().Status(httptest.StatusOK).
+			Body().Equal(body)
+
+		// test accept-language header prefix (i18n wrapper).
+		e.GET("/"+lang).WithHeader("Accept-Language", lang).Expect().Status(httptest.StatusOK).
+			Body().Equal(body)
+
+		// test path prefix (i18n router wrapper).
+		e.GET("/" + lang).Expect().Status(httptest.StatusOK).
+			Body().Equal(body)
+
+		// test path prefix with first part.
+		e.GET("/" + langFirstPart).Expect().Status(httptest.StatusOK).
+			Body().Equal(body)
+	}
 
 	e.GET("/multi").WithQueryString("lang=el-GR").Expect().Status(httptest.StatusOK).
 		Body().Equal(elgrMulti)
 	e.GET("/multi").WithQueryString("lang=en-US").Expect().Status(httptest.StatusOK).
 		Body().Equal(enusMulti)
+
+	// test path prefix (i18n router wrapper).
+	e.GET("/el-gr/multi").Expect().Status(httptest.StatusOK).
+		Body().Equal(elgrMulti)
+	e.GET("/en/multi").Expect().Status(httptest.StatusOK).
+		Body().Equal(enusMulti)
 }

iris.go

@@ -806,7 +806,7 @@ func Raw(f func() error) Runner {
 // It builds the default router with its default macros
 // and the template functions that are very-closed to iris.
 //
-// If error occured while building the Application, the returns type of error will be an *errgroup.Group
+// If error occurred while building the Application, the returns type of error will be an *errgroup.Group
 // which let the callers to inspect the errors and cause, usage:
 //
 // import "github.com/kataras/iris/v12/core/errgroup"

middleware/i18n/i18n.go

@@ -7,11 +7,16 @@ import (
 	"net/http"
 	"reflect"
 	"strings"
+	"sync"
 
 	"github.com/iris-contrib/i18n"
 	"github.com/kataras/iris/v12/context"
 )
 
+// If `Config.Default` is missing and `Config.Languages` or `Config.Alternatives` contains this key then it will set as the default locale,
+// no need to be exported(see `Config.Default`).
+const defLang = "en-US"
+
 // Config the i18n options.
 type Config struct {
 	// Default set it if you want a default language.
@@ -71,6 +76,16 @@ func (c *Config) Exists(lang string) (string, bool) {
 	return i18n.IsExistSimilar(lang)
 }
 
+// all locale files passed, we keep them in order
+// to check if a file is already passed by `New` or `NewWrapper`,
+// because we don't have a way to check before the appending of
+// a locale file and the same locale code can be used more than one to register different file names (at runtime too).
+var (
+	localeFilesSet = make(map[string]struct{})
+	localesMutex   sync.RWMutex
+	once           sync.Once
+)
+
 func (c *Config) loadLanguages() {
 	if len(c.Languages) == 0 {
 		panic("field Languages is empty")
@@ -82,14 +97,8 @@ func (c *Config) loadLanguages() {
 		}
 	}
 
-	firstlanguage := ""
 	// load the files
 	for k, langFileOrFiles := range c.Languages {
-		if i18n.IsExist(k) {
-			// if it is already stored through middleware (`New`) then skip it.
-			continue
-		}
-
 		// remove all spaces.
 		langFileOrFiles = strings.Replace(langFileOrFiles, " ", "", -1)
 		// note: if only one, then the first element is the "v".
@@ -100,21 +109,34 @@ func (c *Config) loadLanguages() {
 				v += ".ini"
 			}
 
+			localesMutex.RLock()
+			_, exists := localeFilesSet[v]
+			localesMutex.RUnlock()
+			if !exists {
+				localesMutex.Lock()
 				err := i18n.SetMessage(k, v)
+				// fmt.Printf("add %s = %s\n", k, v)
 				if err != nil && err != i18n.ErrLangAlreadyExist {
 					panic(fmt.Sprintf("Failed to set locale file' %s' with error: %v", k, err))
 				}
-			if firstlanguage == "" {
-				firstlanguage = k
-			}
-		}
-	}
-	// if not default language set then set to the first of the "Languages".
-	if c.Default == "" {
-		c.Default = firstlanguage
+
+				localeFilesSet[v] = struct{}{}
+				localesMutex.Unlock()
 			}
 
+		}
+	}
+
+	if c.Default == "" {
+		if lang, ok := c.Exists(defLang); ok {
+			c.Default = lang
+		}
+	}
+
+	once.Do(func() { // set global default lang once.
+		// fmt.Printf("set default language: %s\n", c.Default)
 		i18n.SetDefaultLang(c.Default)
+	})
 }
 
 // test file: ../../_examples/miscellaneous/i18n/main_test.go
@@ -144,7 +166,6 @@ func (i *i18nMiddleware) ServeHTTP(ctx context.Context) {
 		if language == "" {
 			// try to get by url parameter
 			language = ctx.URLParam(i.config.URLParameter)
-
 			if language == "" {
 				// then try to take the lang field from the cookie
 				language = ctx.GetCookie(langKey)
@@ -168,14 +189,14 @@ func (i *i18nMiddleware) ServeHTTP(ctx context.Context) {
 		}
 	}
 
+	if language == "" {
+		language = i.config.Default
+	}
+
 	// returns the original key of the language and true
 	// when the language, or something similar exists (e.g. en-US maps to en).
 	if lc, ok := i.config.Exists(language); ok {
 		language = lc
-	} else {
-		// if unexpected language given, the middleware will translate to the default language,
-		// the language key should be also this language instead of the user-given.
-		language = i.config.Default
 	}
 
 	// if it was not taken by the cookie, then set the cookie in order to have it.
@@ -216,6 +237,7 @@ func NewWrapper(c Config) func(http.ResponseWriter, *http.Request, http.HandlerF
 			path = path[:idx]
 		}
 
+		if path != "" {
 			if lang, ok := c.Exists(path); ok {
 				path = r.URL.Path[len(path)+1:]
 				if path == "" {
@@ -225,6 +247,7 @@ func NewWrapper(c Config) func(http.ResponseWriter, *http.Request, http.HandlerF
 				r.URL.Path = path
 				r.Header.Set("Accept-Language", lang)
 			}
+		}
 
 		routerHandler(w, r)
 	}