Merge pull request #771 from gobuffalo/localized-views

Implement #723 - Localized views

middleware/i18n/i18n.go

@@ -2,6 +2,7 @@ package i18n
 
 import (
 	"log"
+	"strings"
 
 	"github.com/gobuffalo/buffalo"
 	"github.com/gobuffalo/packr"
@@ -21,7 +22,7 @@ type LanguageFinder func(*Translator, buffalo.Context) []string
 type Translator struct {
 	// Box - where are the files?
 	Box packr.Box
-	// DefaultLanguage - default is "en-US"
+	// DefaultLanguage - default is passed as a parameter on New.
 	DefaultLanguage string
 	// CookieName - name of the cookie to find the desired language.
 	// default is "lang"
@@ -157,10 +158,26 @@ func defaultLanguageFinder(t *Translator, c buffalo.Context) []string {
 	// try to get the language from a header:
 	acceptLang := r.Header.Get("Accept-Language")
 	if acceptLang != "" {
-		langs = append(langs, acceptLang)
+		langs = append(langs, parseAcceptLanguage(acceptLang)...)
 	}
 
-	// try to get the language from the session:
+	// finally set the default app language as fallback
 	langs = append(langs, t.DefaultLanguage)
 	return langs
 }
+
+// Inspired from https://siongui.github.io/2015/02/22/go-parse-accept-language/
+// Parse an Accept-Language string to get usable lang values for i18n system
+func parseAcceptLanguage(acptLang string) []string {
+	var lqs []string
+
+	langQStrs := strings.Split(acptLang, ",")
+	for _, langQStr := range langQStrs {
+		trimedLangQStr := strings.Trim(langQStr, " ")
+
+		langQ := strings.Split(trimedLangQStr, ";")
+		lq := langQ[0]
+		lqs = append(lqs, lq)
+	}
+	return lqs
+}

middleware/i18n/i18n_test.go

@@ -42,6 +42,15 @@ func app() *buffalo.App {
 		c.Set("Users", usersList)
 		return c.Render(200, r.HTML("format.html"))
 	})
+	app.GET("/localized", func(c buffalo.Context) error {
+		return c.Render(200, r.HTML("localized_view.html"))
+	})
+	// Disable i18n middleware
+	noI18n := func(c buffalo.Context) error {
+		return c.Render(200, r.HTML("localized_view.html"))
+	}
+	app.Middleware.Skip(t.Middleware(), noI18n)
+	app.GET("/localized-disabled", noI18n)
 	return app
 }
 
@@ -101,3 +110,30 @@ func Test_i18n_format_fr(t *testing.T) {
 	res := req.Get()
 	r.Equal("Bonjour Mark !\n\n\t* M. Mark Bates\n\n\t* M. Chuck Berry\n", res.Body.String())
 }
+
+func Test_i18n_Localized_View(t *testing.T) {
+	r := require.New(t)
+
+	w := willie.New(app())
+	// Test with complex Accept-Language
+	req := w.Request("/localized")
+	req.Headers["Accept-Language"] = "en-UK,en-US;q=0.5"
+	res := req.Get()
+	r.Equal("Hello!\n", res.Body.String())
+
+	// Test priority
+	req.Headers["Accept-Language"] = "fr,en-US"
+	res = req.Get()
+	r.Equal("Bonjour !\n", res.Body.String())
+
+	// Test fallback
+	req.Headers["Accept-Language"] = "ru"
+	res = req.Get()
+	r.Equal("Default\n", res.Body.String())
+
+	// Test i18n disabled
+	req = w.Request("/localized-disabled")
+	req.Headers["Accept-Language"] = "en-UK,en-US;q=0.5"
+	res = req.Get()
+	r.Equal("Default\n", res.Body.String())
+}

middleware/i18n/templates/localized_view.en-uk.html

@@ -0,0 +1 @@
+Hello!

middleware/i18n/templates/localized_view.fr.html

@@ -0,0 +1 @@
+Bonjour !

middleware/i18n/templates/localized_view.html

@@ -0,0 +1 @@
+Default

render/template.go

@@ -61,7 +61,32 @@ func (s templateRenderer) exec(name string, data Data) (template.HTML, error) {
 		}
 	}
 
-	source, err := s.TemplatesBox.MustBytes(name)
+	// Try to use localized version
+	templateName := name
+	if languages, ok := data["languages"].([]string); ok {
+		ll := len(languages)
+		if ll > 0 {
+			// Default language is the last in the list
+			defaultLanguage := languages[ll-1]
+			ext := filepath.Ext(name)
+			rawName := strings.TrimSuffix(name, ext)
+
+			for _, l := range languages {
+				var candidateName string
+				if l == defaultLanguage {
+					break
+				}
+				candidateName = rawName + "." + strings.ToLower(l) + ext
+				if s.TemplatesBox.Has(candidateName) {
+					// Replace name with the existing suffixed version
+					templateName = candidateName
+					break
+				}
+			}
+		}
+	}
+
+	source, err := s.TemplatesBox.MustBytes(templateName)
 	if err != nil {
 		return "", err
 	}