var server=http.createServer(function(request, responsehttp) {
    if (request.method == 'POST') {
        var body = '';
        request.on('data', function (data) {
            body += data;
        });
        request.on('end', function () {
            var POST = qs.parse(body);
            processquery(POST, request, responsehttp);
        });
    } else {
        var url_parts = url.parse(request.url, true);
        var query = url_parts.query;
        console.log(query);
        processquery(query, request, responsehttp);
    }
});

function processquery(query, request, responsehttp){
    var returnResult = function (data){
        responsehttp.end(JSON.stringify(data));
    };

    if (!query.command) {
        fileprocess(request, responsehttp);
    }
    responsehttp.writeHead(200, {"Content-Type": "application/json"});
    switch(query.command) {
        case 'logout':
            logout(query, returnResult);
            break;
        case 'login':
            login(query, returnResult);
            break;
    }
}

function login(request, callback) {
    if(request.username==users[request.username] && request.password==users[request.username].password) {
        users[request.username].auth=true;
        var data = {result:'success','message':'login successful'};
        callback(data);
    } else {
        var data = {result:'error','message':'login incorrect'};
        callback(data);
    }
}

function checkAuth(req, res, next) {
  if (!req.session.user_id) {
    res.send('You are not authorized to view this page');
  } else {
    next();
  }
}

app.get('/my_secret_page', checkAuth, function (req, res) {
  res.send('if you are viewing this page it means you are logged in');
});

app.post('/login', function (req, res) {
  var post = req.body;
  if (post.user === 'john' && post.password === 'johnspassword') {
    req.session.user_id = johns_user_id_here;
    res.redirect('/my_secret_page');
  } else {
    res.send('Bad user/pass');
  }
});

app.get('/logout', function (req, res) {
  delete req.session.user_id;
  res.redirect('/login');
});

function checkAuth(req, res, next) {
  // if logined or it's login request, then go next route
  if (isLogin || (req.path === '/login' && req.method === 'POST')) {
    next()
  } else {
    res.send('Not logged in yet.')
  }
}

app.use('/', checkAuth)