我正在使用Node.js，Express和Redis构建一个用于会话管理的网站。无论出于何种原因，如果我有一个会话变量（isLoggedIn在此示例中），并且刷新页面，则不会保存该变量，但是，如果我req.session.save()在设置了变量后调用，则确实会将其保存到Redis（redis-
cli监视器显示此内容-不调用save()表示变量不存在，而调用则save()显示该变量）。

我正在使用它来设置和启动服务器：

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var swig = require('swig');
var session = require('express-session')
var RedisStore = require('connect-redis')(session);

var routes = require('./routes/index');
var users = require('./routes/users');

var app = express();

// Configure the favicon first. This avoids other middleware from processing the request if we know the request is for the favicon.
app.use(favicon(__dirname + '/public/images/favicon.ico'));

// All other requests will require everything else.

// Set up the view engine.
app.set('view engine', 'html');
app.set('views', path.join(__dirname, '/views'));
app.engine('html', swig.renderFile);

// Set up our logger.
app.use(logger('dev'));

// Set up JSON parsing.
app.use(bodyParser.json());

// Set up encoded URL parsing.
app.use(bodyParser.urlencoded());

// Set up the cookie parser.
app.use(cookieParser('thedogsleepsatnight'));

// Set up our session store. This will use Redis as our session management.
app.use(session({
    resave: true,
    saveUninitialized: true,
    secret: "thedogsleepsatnight",
    store: new RedisStore()
}));

app.use(require('stylus').middleware(path.join(__dirname, 'public')));
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', routes);

然后，在那条路线中，我有：

var express = require('express');
var router = express.Router();

router.get('/', function(req, res) {
    console.log(req.session.isLoggedIn);
    if (req.session.isLoggedIn) {
        console.log("Logged in!");
    } else {
        console.log("Not logged in");
    }

    res.render('index');
});

router.post('/login', function(req, res) {
    console.log("Going to set isLoggedIn. Currently: " + req.session.isLoggedIn);
    req.session.isLoggedIn = true;
    console.log("Set isLoggedIn. Currently: " + req.session.isLoggedIn);
});

module.exports = router;

由此，我应该能够导航到/login，将会话设置为isLoggedIn为true，并且应该将其自动保存到Redis。之后，转到/应当告诉我我已经登录。加载/login确实设置了变量，第二个日志显示了该信息，但是加载/表明我没有登录。redis-
cli monitor显示

1414076171.241836 "setex" "sess:FIDJ9qDbX_0u9pzlC6VZEW76zZcyiPME" "86400" "{\"cookie\":{\"originalMaxAge\":null,\"expires\":null,\"httpOnly\":true,\"path\":\"/\"}}"

保存后，其中不包含isLoggedIn变量，但添加了req.session.save()显示：

1414076475.601644 "setex" "sess:FIDJ9qDbX_0u9pzlC6VZEW76zZcyiPME" "86400" "{\"cookie\":{\"originalMaxAge\":null,\"expires\":null,\"httpOnly\":true,\"path\":\"/\"},\"isLoggedIn\":true}"

关于我看到的req.session.save()所有示例均未使用时为什么要致电的任何想法？