Express会话Cookie不能持久保存在子域中

Question

我正在使用快速会话。它在本地运行良好，但是当我将其部署到生产环境时，前端（frontend.example.com）不会保留从API（api.example.com）返回的cookie。我用withCredentials:true（axios）发出前端请求。这是我在后端的代码（为简洁起见进行了编辑）：

const cors = require('cors');
var session = require('express-session');
var SequelizeStore = require('connect-session-sequelize')(session.Store);

const sessionStore = new SequelizeStore({
    db: db.sequelize,
    checkExpirationInterval: 15 * 60 * 1000, // The interval at which to cleanup expired sessions in milliseconds.
    expiration: sessionExpiration,
});
sessionStore.sync();

const app = express();

// corsOrigin is a function that returns a matching domain
app.use(cors({ origin: corsOrigin, credentials: true }));

app.use(
    session({
        name: 'sid',
        secret: process.env.SESSION_SECRET,
        store: sessionStore,
        saveUninitialized: true,
        resave: false,
        proxy: false,
        cookie: {
            maxAge: sessionExpiration,
            httpOnly: false,
            domain: '.example.com',
            secure: false,
        },
    })
);

我认为这是一个子域/跨域问题，但是我希望domain: '.example.com'能解决该问题。有什么想法吗？