From 1f82828c82062019a7b22bf020827f6550617401 Mon Sep 17 00:00:00 2001
From: Thorsten Sommer <service@sommer-engineering.com>
Date: Sat, 8 Nov 2014 18:37:33 +0100
Subject: [PATCH] I18N

+ Added language detection and default language
---
 ConfigurationDB/CheckConfiguration.go |  1 +
 Tools/Init.go                         |  3 ++
 Tools/RequestLanguage.go              | 51 +++++++++++++++++++++++++++
 Tools/ResponseLanguage.go             |  9 +++++
 Tools/SchemeLanguage.go               | 20 +++++++++++
 Tools/Variables.go                    |  1 +
 6 files changed, 85 insertions(+)
 create mode 100644 Tools/RequestLanguage.go
 create mode 100644 Tools/ResponseLanguage.go
 create mode 100644 Tools/SchemeLanguage.go

diff --git a/ConfigurationDB/CheckConfiguration.go b/ConfigurationDB/CheckConfiguration.go
index a2e4bc1..9fd36c7 100644
--- a/ConfigurationDB/CheckConfiguration.go
+++ b/ConfigurationDB/CheckConfiguration.go
@@ -10,6 +10,7 @@ func checkConfiguration() {
 	Log.LogShort(senderName, LM.CategorySYSTEM, LM.LevelINFO, LM.MessageNameDATABASE, `Check now the configuration database.`)
 	defer Log.LogShort(senderName, LM.CategorySYSTEM, LM.LevelINFO, LM.MessageNameDATABASE, `Done checking the configuration database.`)
 
+	CheckSingleConfigurationPresentsAndAddIfMissing(`DefaultLanguageCode`, `en-GB`)
 	CheckSingleConfigurationPresentsAndAddIfMissing(`AdminWebServerBinding`, `127.0.0.1:60000`)
 	CheckSingleConfigurationPresentsAndAddIfMissing(`AdminWebServerEnabled`, `True`)
 	CheckSingleConfigurationPresentsAndAddIfMissing(`AdminWebServerReadTimeoutSeconds`, `10`)
diff --git a/Tools/Init.go b/Tools/Init.go
index 40cde30..482b0a3 100644
--- a/Tools/Init.go
+++ b/Tools/Init.go
@@ -31,4 +31,7 @@ func init() {
 	allHostsIPAddresses := ReadAllIPAddresses4ThisHost()
 	port := ConfigurationDB.Read(`PublicWebServerPort`)
 	localIPAddressAndPort = allHostsIPAddresses[0] + `:` + port
+
+	// Read the default language:
+	defaultLanguage = ConfigurationDB.Read(`DefaultLanguageCode`)
 }
diff --git a/Tools/RequestLanguage.go b/Tools/RequestLanguage.go
new file mode 100644
index 0000000..396621e
--- /dev/null
+++ b/Tools/RequestLanguage.go
@@ -0,0 +1,51 @@
+package Tools
+
+import (
+	"net/http"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+func GetRequestLanguage(request *http.Request) (resultLangs Languages) {
+	languageCodeForm := request.FormValue(`lang`)
+	languageCodeHeader := request.Header.Get(`Accept-Language`)
+
+	if languageCodeForm != `` && ((len(languageCodeForm) == 2) || (len(languageCodeForm) == 5 && strings.Contains(languageCodeForm, `-`))) {
+		resultLangs = make(Languages, 1)
+		resultLangs[0].Factor = 1.0
+		resultLangs[0].Language = strings.ToLower(languageCodeForm)
+		return
+	}
+
+	if languageCodeHeader == `` {
+		resultLangs = make(Languages, 1)
+		resultLangs[0].Factor = 1.0
+		resultLangs[0].Language = defaultLanguage
+		return
+	}
+
+	values := strings.Split(languageCodeHeader, `,`)
+	langs := make(Languages, len(values))
+	for n, langData := range values {
+		if factorData := strings.Split(langData, `;q=`); len(factorData) == 2 {
+			if factor, errFactor := strconv.ParseFloat(factorData[1], 32); errFactor != nil {
+				langs[n] = Language{}
+				langs[n].Language = strings.ToLower(strings.Trim(factorData[0], ` `))
+				langs[n].Factor = 1.0
+			} else {
+				langs[n] = Language{}
+				langs[n].Language = strings.ToLower(strings.Trim(factorData[0], ` `))
+				langs[n].Factor = float32(factor)
+			}
+		} else {
+			langs[n] = Language{}
+			langs[n].Language = strings.ToLower(strings.Trim(langData, ` `))
+			langs[n].Factor = 1.0
+		}
+	}
+
+	sort.Sort(langs)
+	resultLangs = langs
+	return
+}
diff --git a/Tools/ResponseLanguage.go b/Tools/ResponseLanguage.go
new file mode 100644
index 0000000..efadfe0
--- /dev/null
+++ b/Tools/ResponseLanguage.go
@@ -0,0 +1,9 @@
+package Tools
+
+import (
+	"net/http"
+)
+
+func SendChosenLanguage(response http.ResponseWriter, lang Language) {
+	response.Header().Add(`Content-Language`, lang.Language)
+}
diff --git a/Tools/SchemeLanguage.go b/Tools/SchemeLanguage.go
new file mode 100644
index 0000000..3e247c2
--- /dev/null
+++ b/Tools/SchemeLanguage.go
@@ -0,0 +1,20 @@
+package Tools
+
+type Language struct {
+	Language string
+	Factor   float32
+}
+
+type Languages []Language
+
+func (lang Languages) Len() int {
+	return len(lang)
+}
+
+func (lang Languages) Less(i, j int) bool {
+	return lang[i].Factor > lang[j].Factor
+}
+
+func (lang Languages) Swap(i, j int) {
+	lang[i], lang[j] = lang[j], lang[i]
+}
diff --git a/Tools/Variables.go b/Tools/Variables.go
index c0c7c38..a5a411b 100644
--- a/Tools/Variables.go
+++ b/Tools/Variables.go
@@ -10,4 +10,5 @@ var (
 	localIPAddressAndPort string    = `127.0.0.1:60000`
 	ipAddresses           []string  = nil
 	internalCommPassword  string    = ``
+	defaultLanguage       string    = `en`
 )