Question

I have set up my express/connect app to use sessions with redis as the store:

app.use(express.session({
        secret: "secret key here",
        store: app.redisStore,
        cookie: { maxAge: 600000 }
    }));

I have created my own flash message system by doing the following:

module.exports = function (app) {
    'use strict';

    //set-up session messages
    app.use(function (req, res, next) {

        /* set up flash*/
        if (req.session.flash === "undefined") {
            req.session.flash = [];
        }

        res.locals.messages = function () {
            var messages = req.session.flash;
            //clear out messages
            req.session.flash = [];
            return messages;
        };
        ...

Then essentially I just push flash message objects into the flash array whenever I need them. Every time the message function is used they get cleared out. This seems to work for the most part; however, while logging out I use the regenerate function and flash becomes undefined:

function logout(req, res) {
            var currentUser = req.session.currentUser;
            req.session.regenerate(function (err) {
                req.session.flash.push({"type": "info", "message": "You have been logged out."});
                console.log(currentUser + " Logged Out");
                res.redirect("/login");
                return;
            });
        }

Which seems to make sense. Regenerate obliterates the session, and since it happens after the initial request flash becomes undefined. To avoid any future problems like this I am wondering if there is there some sort of initialize function for sessions that I can override or hook into? I’d use this to set some default session values every time a session is started or regenerated.

Side-question: Is flash actually getting saved in redis?

Answer 1

To avoid any future problems like this I am wondering if there is
there some sort of initialize function for sessions that I can
override or hook into? I’d use this to set some default session values
every time a session is started or regenerated.

No, the way you are doing this is correct. If you want to attach multiple actions to regenerate method, then you can also try something like this:

var EventEmitter = require('events').EventEmitter;
var session_events = new EventEmitter( );

module.exports = function (app) {
    'use strict';

    //set-up session messages
    app.use(function (req, res, next) {
        var regenerate = req.session.regenerate;
        req.session.regenerate = function() {
            session_events.emit( "session_regenerated", req );
            regenerate.apply( req.session, arguments );
        };

        /* set up flash*/
        if (req.session.flash === "undefined") {
            session_events.emit( "session_initializing", req );
        }
        // other code goes here
    });
}

Then you can simply do:

session_events.on( "session_regenerated", function(req) {
    req.session.flash.push({"type": "info", "message": "You have been logged out."});
});
session_events.on( "session_initializing", function(req) {
    req.session.flash = [];
});

This is a monkey patch, though ( at least the .regenerate overriding ), so I advice writing your own session store, which is not difficult at all, since session is nothing else then an entry in Redis/any other storage.

Side-question: Is flash actually getting saved in redis?

Yes, everything attached to session goes to session store ( Redis in your case ).