closes #2377

public/language/en_GB/error.json

@@ -85,5 +85,7 @@
 	"not-enough-reputation-to-downvote": "You do not have enough reputation to downvote this post",
 	"not-enough-reputation-to-flag": "You do not have enough reputation to flag this post",
 
-	"reload-failed": "NodeBB encountered a problem while reloading: \"%1\". NodeBB will continue to serve the existing client-side assets, although you should undo what you did just prior to reloading."
+	"reload-failed": "NodeBB encountered a problem while reloading: \"%1\". NodeBB will continue to serve the existing client-side assets, although you should undo what you did just prior to reloading.",
+
+	"registration-error": "Registration Error"
 }

src/controllers/index.js

@@ -179,6 +179,7 @@ Controllers.register = function(req, res, next) {
 	data.minimumPasswordLength = meta.config.minimumPasswordLength;
 	data.termsOfUse = meta.config.termsOfUse;
 	data.regFormEntry = [];
+	data.error = req.flash('error')[0];
 
 	plugins.fireHook('filter:register.build', {req: req, res: res, templateData: data}, function(err, data) {
 		if (err && process.env === 'development') {

src/routes/authentication.js

@@ -207,14 +207,20 @@
 			}
 		}
 
-		if (!userData.username || userData.username.length < meta.config.minimumUsernameLength) {
-			return res.redirect(nconf.get('relative_path') + '/register?error=[[error:username-too-short]]');
-		} else if (!userData.username || userData.username.length > meta.config.maximumUsernameLength) {
-			return res.redirect(nconf.get('relative_path') + '/register?error=[[error:username-too-long]]');
-		}
-
 		var uid;
 		async.waterfall([
+			function(next) {
+				if (!userData.username || userData.username.length < meta.config.minimumUsernameLength) {
+					return next(new Error('[[error:username-too-short]]'));
+				}
+				next();
+			},
+			function(next) {
+				if (!userData.username || userData.username.length > meta.config.maximumUsernameLength) {
+					return next(new Error('[[error:username-too-long'));
+				}
+				next();
+			},
 			function(next) {
 				plugins.fireHook('filter:register.check', {req: req, res: res, userData: userData}, next);
 			},
@@ -236,7 +242,8 @@
 			}
 		], function(err, data) {
 			if (err) {
-				return res.redirect(nconf.get('relative_path') + '/register?error=' + err.message);
+				req.flash('error', err.message);
+				return res.redirect(nconf.get('relative_path') + '/register');
 			}
 			res.redirect(nconf.get('relative_path') + (data.referrer ? data.referrer : '/'));
 		});