node.js - Flash 消息不适用于 connect-session-sequelize

Question

我有一个 node.js Web 应用程序，它可以在 MongoDB 和 Sequelize (PostgreSQL) 之间切换以进行 session 。对于这两种情况，我还在连接闪存(也尝试过 express-flash)中间件中分层以用于闪存消息。简而言之，MongoDB 有效，Sequelize 无效。

该应用程序具有用户可以编辑的“包”概念。用户编辑包成功后，我设置了一个flash message

"${timestamp} Package ${pkgID} successfully updated." 

和重定向。使用 Sequelize (connect-session-sequelize)，即使我可以在数据库中看到它，也不会显示 Flash 消息，如果我刷新页面，它就会出现。

这是 Sequelize session 的设置:

var cookieParser = require('cookie-parser');
var expSession = require('express-session');
var flash = require('express-flash');

app.use(cookieParser(process.env.COOKIE_SECRET));

if (sessionDBVendor === 'postgres') {
    let models = require('./models/postgres');
    var SequelizeSessionStore = require('connect-session-sequelize')(expSession.Store);
    var sequelizeSessionStore = new SequelizeSessionStore({
        db: models.sequelize,
        table: 'Session'
    });
    sequelizeSessionStore.on('set', function (data) {
        debug(`SequelizeSessionStore: Session ${data} UPDATED.`);
    });
    app.use(
        expSession({
            secret: process.env.COOKIE_SECRET,
            store: sequelizeSessionStore,
            resave: false, // we support the touch method so per the express-session docs this should be set to false 
            proxy: false, // if you do SSL outside of node.
            saveUninitialized: false,
        })
    );
}
app.use(flash());

查看 connect-session-sequelize 源代码，我发现我可以将“connect:session-sequelize”添加到我的 DEBUG 环境变量中以在控制台中获取额外信息。这是控制台日志的有趣部分，添加了一些格式、一些空行和数字。

      connect:session-sequelize INSERT "DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI" +5s
    Executing (default): SELECT "sid", "userId", "expires", "data", "createdAt", "updatedAt" 
            FROM "webjmp"."sessions" AS "Session" 
            WHERE "Session"."sid" = 'DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI';
      connect:session-sequelize SELECT "DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI" +10ms
    Executing (default): SELECT "sid", "userId", "expires", "data", "createdAt", "updatedAt" 
            FROM "webjmp"."sessions" AS "Session" 
            WHERE "Session"."sid" = 'DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI';

(1)
    Executing (default): UPDATE "webjmp"."sessions" SET "expires"='2017-02-21 15:53:54.738 +00:00',
            "data"='{"cookie":{"originalMaxAge":null,"expires":null,"httpOnly":true,"path":"/"},
               "flash":{"flashSuccess":["{02/20/2017 10:53:49} Package 58a718a0280081343eeab6d9 was successfully updated."]}}',
            "updatedAt"='2017-02-20 15:53:54.756 +00:00' WHERE "sid" = 'DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI'

(2)
      connect:session-sequelize FOUND DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI with data 
         {"cookie":{"originalMaxAge":null,"expires":null,"httpOnly":true,"path":"/"},"flash":{}} +17ms

    Executing (default): SELECT "Package"."_id", "Package"."title", "Package"."description", 
            {content removed for brevity}
            FROM "webjmp"."packages" AS "Package" 
            {content removed for brevity}
            ORDER BY "Package"."timestamp" DESC;
    ::1 - - [20/Feb/2017:15:53:54 +0000] "POST /packages/58a718a0280081343eeab6d9 HTTP/1.1" 302 62
      packages ID of package in returned list: 58a718a0280081343eeab6d9 +166ms
      packages ID of package in returned list: 58a716c35326d0b0380c0b37 +0ms
      packages ID of package in returned list: 58a474c55c9f18cc31cb0e2a +0ms
      packages ID of package in returned list: 58a45dfa51f335c015d8591f +0ms
      packages ID of package in returned list: 589cc7f30a333d1864b07bb2 +0ms

(3)
      packages listPackages: flashSuccess: [] +0ms

      connect:session-sequelize TOUCH "DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI" +92ms
    Executing (default): UPDATE "webjmp"."sessions" SET "expires"='2017-02-21 15:53:55.023 +00:00',
            "updatedAt"='2017-02-20 15:53:55.024 +00:00' 
            WHERE "sid" = 'DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI'
    ::1 - - [20/Feb/2017:15:53:55 +0000] "GET /packages HTTP/1.1" 200 6909
      connect:session-sequelize SELECT "DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI" +14ms
    Executing (default): SELECT "sid", "userId", "expires", "data", "createdAt", "updatedAt" 
            FROM "webjmp"."sessions" AS "Session" 
            WHERE "Session"."sid" = 'DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI';
      connect:session-sequelize SELECT "DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI" +6ms
    Executing (default): SELECT "sid", "userId", "expires", "data", "createdAt", "updatedAt" 
            FROM "webjmp"."sessions" AS "Session" WHERE "Session"."sid" = 'DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI';

(4)
      connect:session-sequelize FOUND DnVIEQiTfaxKZjYgC7uHmKbelJvJBzrI with data 
            {"cookie":{"originalMaxAge":null,"expires":null,"httpOnly":true,"path":"/"},
            "flash":{"flashSuccess":["{02/20/2017 10:53:49} Package 58a718a0280081343eeab6d9 was successfully updated."]}} +3ms

请注意，在(1)处，完成了 UPDATE，并且在更新的“数据”中，“flash”包含一个对象:

"flash":{"flashSuccess":["{02/20/2017 10:53:49} Package 58a718a0280081343eeab6d9 was successfully updated."]}

那是我的闪光信息。但是，请注意 (2)，connect-session-sequelize debug 会吐出一条 FOUND 消息，显示它找到的 session ，并且在它显示的 session 对象中，flash 为空:

"flash":{}

紧接着，在 (3) 处，我的代码尝试检索“flashSuccess” flash 消息，但它出现了一个空数组。但是，在 (4) 处，connect-session-sequelize 会吐出另一条 FOUND 调试消息，其中包含 flash 消息:

"flash":{"flashSuccess":["{02/20/2017 10:53:49} Package 58a718a0280081343eeab6d9 was successfully updated."]}

如果我检查数据库，它就在那里。

就好像设置 flash 消息的 UPDATE 是异步发生的，并且在 (2) 处检索 session 时尚未完成，但稍后它会显示出来。但是我尝试在设置 flash 消息后抛出 setTimeout() ，但无济于事。

任何想法这里发生了什么？

更新:我添加了第三个 session 存储选项，它使用 connect-pg-simple 中间件在 PostgreSQL 中存储 session 。使用该选项，Flash 消息可以正常工作。 connect-session-sequelize 似乎是个奇怪的人。

Answer 1

在这里回答我自己的问题，但在 issues board for connect-session-sequelize 上指出 express-session 在这些 flash 消息场景中存在竞争条件，并且需要在设置 flash 消息后调用 req.session.save(cb)，返回响应回调，以避免这种情况。例如:

req.flash('flashError', err.message);
req.session.save(function() {
    res.redirect('/packages');
});

这样做解决了问题。