Merge pull request #5616 from NodeBB/auto-lang

Automatically detect user language based on browser accepts header

install/data/defaults.json

@@ -35,5 +35,6 @@
     "allowPrivateGroups": 1,
     "unreadCutoff": 2,
     "bookmarkThreshold": 5,
-    "topicsPerList": 20
+    "topicsPerList": 20,
+    "autoDetectLang": 1
 }

public/language/en-GB/admin/general/languages.json

@@ -1,5 +1,6 @@
 {
 	"language-settings": "Language Settings",
 	"description": "The default language determines the language settings for all users who are visiting your forum. <br />Individual users can override the default language on their account settings page.",
-	"default-language": "Default Language"
+	"default-language": "Default Language",
+	"auto-detect": "Auto Detect Language Setting for Guests"
 }

public/src/modules/helpers.js

@@ -176,7 +176,8 @@
 		}).join('');
 	};
 
-	helpers.localeToHTML = function (locale) {
+	helpers.localeToHTML = function (locale, fallback) {
+		locale = locale || fallback || 'en-GB';
 		return locale.replace('_', '-');
 	};
 

src/controllers/admin/languages.js

@@ -18,6 +18,7 @@ languagesController.get = function (req, res, next) {
 
 		res.render('admin/general/languages', {
 			languages: languages,
+			autoDetectLang: parseInt(meta.config.autoDetectLang, 10) === 1,
 		});
 	});
 };

src/languages.js

@@ -4,7 +4,7 @@ var fs = require('fs');
 var path = require('path');
 var async = require('async');
 
-var Languages = {};
+var Languages = module.exports;
 var	languagesPath = path.join(__dirname, '../build/public/language');
 
 Languages.init = function (next) {
@@ -27,10 +27,13 @@ Languages.get = function (language, namespace, callback) {
 	});
 };
 
-Languages.list = function (callback) {
-	var languages = [];
+var codeCache = null;
+Languages.listCodes = function (callback) {
+	if (codeCache && codeCache.length) {
+		return callback(null, codeCache);
+	}
 
-	fs.readdir(languagesPath, function (err, files) {
+	fs.readFile(path.join(languagesPath, 'metadata.json'), function (err, buffer) {
 		if (err && err.code === 'ENOENT') {
 			return callback(null, []);
 		}
@@ -38,43 +41,59 @@ Languages.list = function (callback) {
 			return callback(err);
 		}
 
-		async.each(files, function (folder, next) {
-			fs.stat(path.join(languagesPath, folder), function (err, stat) {
-				if (err) {
-					return next(err);
-				}
+		var parsed;
+		try {
+			parsed = JSON.parse(buffer.toString());
+		} catch (e) {
+			return callback(e);
+		}
 
-				if (!stat.isDirectory()) {
-					return next();
-				}
-
-				var configPath = path.join(languagesPath, folder, 'language.json');
-
-				fs.readFile(configPath, function (err, buffer) {
-					if (err && err.code !== 'ENOENT') {
-						return next(err);
-					}
-					if (buffer) {
-						var lang = JSON.parse(buffer.toString());
-						if (lang.name && lang.code && lang.dir) {
-							languages.push(lang);
-						}
-					}
-					next();
-				});
-			});
-		}, function (err) {
-			if (err) {
-				return callback(err);
-			}
-			// Sort alphabetically
-			languages = languages.sort(function (a, b) {
-				return a.code > b.code ? 1 : -1;
-			});
-
-			callback(err, languages);
-		});
+		var langs = parsed.languages;
+		codeCache = langs;
+		callback(null, langs);
 	});
 };
 
-module.exports = Languages;
+var listCache = null;
+Languages.list = function (callback) {
+	if (listCache && listCache.length) {
+		return callback(null, listCache);
+	}
+
+	Languages.listCodes(function (err, codes) {
+		if (err) {
+			return callback(err);
+		}
+
+		async.map(codes, function (folder, next) {
+			var configPath = path.join(languagesPath, folder, 'language.json');
+
+			fs.readFile(configPath, function (err, buffer) {
+				if (err && err.code === 'ENOENT') {
+					return next();
+				}
+				if (err) {
+					return next(err);
+				}
+				try {
+					var lang = JSON.parse(buffer.toString());
+					next(null, lang);
+				} catch (e) {
+					next(e);
+				}
+			});
+		}, function (err, languages) {
+			if (err) {
+				return callback(err);
+			}
+
+			// filter out invalid ones
+			languages = languages.filter(function (lang) {
+				return lang.code && lang.name && lang.dir;
+			});
+
+			listCache = languages;
+			callback(null, languages);
+		});
+	});
+};

src/meta/languages.js

@@ -102,6 +102,25 @@ function getTranslationTree(callback) {
 			});
 		},
 
+		// save a list of languages to `${buildLanguagesPath}/metadata.json`
+		// avoids readdirs later on
+		function (ref, next) {
+			async.waterfall([
+				function (next) {
+					mkdirp(buildLanguagesPath, next);
+				},
+				function (x, next) {
+					fs.writeFile(path.join(buildLanguagesPath, 'metadata.json'), JSON.stringify({
+						languages: ref.languages.sort(),
+						namespaces: ref.namespaces.sort(),
+					}), next);
+				},
+				function (next) {
+					next(null, ref);
+				},
+			], next);
+		},
+
 		// for each language and namespace combination,
 		// run through core and all plugins to generate
 		// a full translation hash

src/middleware/header.js

@@ -133,6 +133,7 @@ module.exports = function (middleware) {
 				templateValues.customJS = templateValues.useCustomJS ? meta.config.customJS : '';
 				templateValues.maintenanceHeader = parseInt(meta.config.maintenanceMode, 10) === 1 && !results.isAdmin;
 				templateValues.defaultLang = meta.config.defaultLang || 'en-GB';
+				templateValues.userLang = res.locals.config.userLang;
 				templateValues.privateUserInfo = parseInt(meta.config.privateUserInfo, 10) === 1;
 				templateValues.privateTagListing = parseInt(meta.config.privateTagListing, 10) === 1;
 

src/views/admin/general/languages.tpl

@@ -16,6 +16,17 @@
 					</select>
 				</div>
 			</form>
+
+			<form class="row">
+				<div class="form-group col-sm-6">
+					<div class="checkbox">
+						<label class="mdl-switch mdl-js-switch mdl-js-ripple-effect">
+							<input class="mdl-switch__input" type="checkbox" data-field="autoDetectLang" <!-- IF autoDetectLang -->checked<!-- ENDIF autoDetectLang -->/>
+							<span class="mdl-switch__label">[[admin/general/languages:auto-detect]]</span>
+						</label>
+					</div>
+				</div>
+			</form>
 		</div>
 	</div>
 </div>

src/webserver.js

@@ -55,13 +55,16 @@ module.exports.listen = function (callback) {
 	callback = callback || function () { };
 	emailer.registerApp(app);
 
-	setupExpressApp(app);
-
-	helpers.register();
-
-	logger.init(app);
-
 	async.waterfall([
+		function (next) {
+			setupExpressApp(app, next);
+		},
+		function (next) {
+			helpers.register();
+
+			logger.init(app);
+			next();
+		},
 		initializeNodeBB,
 		function (next) {
 			winston.info('NodeBB Ready');
@@ -110,7 +113,7 @@ function initializeNodeBB(callback) {
 	});
 }
 
-function setupExpressApp(app) {
+function setupExpressApp(app, callback) {
 	var middleware = require('./middleware');
 
 	var relativePath = nconf.get('relative_path');
@@ -155,6 +158,8 @@ function setupExpressApp(app) {
 	var toobusy = require('toobusy-js');
 	toobusy.maxLag(parseInt(meta.config.eventLoopLagThreshold, 10) || 100);
 	toobusy.interval(parseInt(meta.config.eventLoopInterval, 10) || 500);
+
+	setupAutoLocale(app, callback);
 }
 
 function setupFavicon(app) {
@@ -188,6 +193,35 @@ function setupCookie() {
 	return cookie;
 }
 
+function setupAutoLocale(app, callback) {
+	languages.listCodes(function (err, codes) {
+		if (err) {
+			return callback(err);
+		}
+
+		var defaultLang = meta.config.defaultLang || 'en-GB';
+
+		var langs = [defaultLang].concat(codes).filter(function (el, i, arr) {
+			return arr.indexOf(el) === i;
+		});
+
+		app.use(function (req, res, next) {
+			if (parseInt(req.uid, 10) > 0 || parseInt(meta.config.autoDetectLang, 10) !== 1) {
+				return next();
+			}
+
+			var lang = req.acceptsLanguages(langs);
+			if (!lang) {
+				return next();
+			}
+			req.query.lang = lang;
+			next();
+		});
+
+		callback();
+	});
+}
+
 function listen(callback) {
 	callback = callback || function () { };
 	var port = parseInt(nconf.get('port'), 10);

test/locale-detect.js

@@ -0,0 +1,41 @@
+'use strict';
+
+var	assert = require('assert');
+var nconf = require('nconf');
+var request = require('request');
+
+var meta = require('../src/meta');
+
+describe('Language detection', function () {
+	it('should detect the language for a guest', function (done) {
+		request(nconf.get('url') + '/api/config', {
+			headers: {
+				'Accept-Language': 'de-DE,de;q=0.5',
+			},
+		}, function (err, res, body) {
+			assert.ifError(err);
+			assert.ok(body);
+
+			assert.strictEqual(JSON.parse(body).userLang, 'de');
+			done();
+		});
+	});
+
+	it('should do nothing when disabled', function (done) {
+		meta.configs.set('autoDetectLang', 0, function (err) {
+			assert.ifError(err);
+
+			request(nconf.get('url') + '/api/config', {
+				headers: {
+					'Accept-Language': 'de-DE,de;q=0.5',
+				},
+			}, function (err, res, body) {
+				assert.ifError(err);
+				assert.ok(body);
+
+				assert.strictEqual(JSON.parse(body).userLang, 'en-GB');
+				done();
+			});
+		});
+	});
+});