Question

我有一个可以在MongoDB和Sequelize（PostgreSQL）之间切换的node.js网络应用程序。对于两者，我还在连接闪存（也尝试过快速闪存）中间件中进行闪存消息的分层。简而言之，MongoDB的工作原理，Sequelize没有。

该应用程序具有用户可以编辑的“包”概念。用户成功编辑包后，我设置了

的flash消息

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

并重定向。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，那么会出现。

以下是Sequelize会话的设置：

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，我发现我可以在我的DEBUG环境变量中添加“connect：session-sequelize”以在控制台中获取额外信息。以下是控制台日志的有趣部分，其中包含一些格式，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，UPDATE完成，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."]}

这是我的flash消息。但是，请注意（2），connect-session-sequelize debug吐出一条FOUND消息，显示它找到的会话，并且在它显示的会话对象中，flash 为空：

"flash":{}

就在那之后，在（3），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），connect-session-sequelize吐出另一个FOUND调试消息，并且其中有一条flash消息：

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

如果我检查数据库，那就是。

几乎就像设置flash消息的UPDATE是异步发生的，并且在（2）处检索会话时尚未完成，但之后它会显示出来。但我尝试在设置flash消息后抛出一个setTimeout（），但无济于事。

有什么想法在这里发生了什么？

更新：我添加了第三个会话存储选项，它使用connect-pg-simple中间件在PostgreSQL中存储会话。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this table指出快递会话在这些flash消息场景中有竞争条件，并且需要在设置后调用req.session.save（cb） flash消息，返回回调中的响应，以避免这种情况。例如：

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

这样做解决了这个问题。

Flash消息无法使用connect-session-sequelize

1 个答案: