added sample app for client-server authentication

server/controllers/auth.js

@@ -0,0 +1,46 @@
+var passport =  require('passport')
+    , User = require('../models/User.js');
+
+module.exports = {
+    register: function(req, res, next) {
+        try {
+            User.validate(req.body);
+        }
+        catch(err) {
+            return res.send(400, err.message);
+        }
+
+        User.addUser(req.body.username, req.body.password, req.body.role, function(err, user) {
+            if(err === 'UserAlreadyExists') return res.send(403, "User already exists");
+            else if(err)                    return res.send(500);
+
+            req.logIn(user, function(err) {
+                if(err)     { next(err); }
+                else        { res.json(200, { "role": user.role, "username": user.username }); }
+            });
+        });
+    },
+
+    login: function(req, res, next) {
+        passport.authenticate('local', function(err, user) {
+
+            if(err)     { return next(err); }
+            if(!user)   { return res.send(400); }
+
+
+            req.logIn(user, function(err) {
+                if(err) {
+                    return next(err);
+                }
+
+                if(req.body.rememberme) req.session.cookie.maxAge = 1000 * 60 * 60 * 24 * 7;
+                res.json(200, { "role": user.role, "username": user.username });
+            });
+        })(req, res, next);
+    },
+
+    logout: function(req, res) {
+        req.logout();
+        res.send(200);
+    }
+};