How to write into an Expressjs session with Primus - express

Question

Using ExpressJs 4 and Primus, I can share the Express session.
primus.on('connection', function (spark) {
var req = spark.request; // Here, I have the Express session
req.session.foo = 'bar'; // I try to write into the session.
});
When I write the { foo: 'bar' } value into the session, I can't retrieve it from a standard http express call.
app.get('/api/...', function (req, res) {
console.log(req.session.foo); // Print undefined :'(
res.send();
});
The output is undefined. Could you explain me why?
Thanks.

Answer 1

According to the express-session documentation, we can save the session to the store.
https://github.com/expressjs/session#sessionsave
primus.on('connection', function (spark) {
var req = spark.request; // Here, I have the Express session
req.session.foo = 'bar'; // I try to write into the session.
req.session.save(); // Save the session to the store
});
Then, it works well!

Answer 2

Here's how I have it working currently (Express 4.13.4; Primus 4.0.5)
App.js
var express = require('express');
var cookieParser = require('cookie-parser');
var session = require('express-session');
var sockjs = require('sockjs');
var http = require('http');
var Primus = require('primus');
var realtime_functions = require('./custom_modules/realtime_functions.js');
var app = express();
var app_secret_key = 'app secret';
var cookieparser = cookieParser(app_secret_key);
var sessionstore = new session.MemoryStore();
app.use(cookieparser);
app.use(session({
secret: app_secret_key,
saveUninitialized: false,
resave: false,
store: sessionstore
}));
realtime_functions(app, cookieparser, sessionstore);
realtime_functions.js
var primus_start = function(express, cookies, store) {
var server = http.createServer(express);
var primus = new Primus(server, {transformer: 'SockJS', parser: 'JSON'})
primus.use('rooms', primusRooms)
server.listen(3000, '0.0.0.0');
primus.before('cookies', cookies);
primus.before('session', function session(req, res, next) {
try {
var sid = req.signedCookies['connect.sid'];
if (!sid) { return next(); }
req.pause();
store.get(sid, function (err, session) {
if (err) {
primus.emit('log', 'error', err);
return next();
}
if(session) {
req.sessionID = sid;
req.sessionStore = store;
req.thesession = store.createSession(req, session);
}
req.resume();
next();
});
} catch(error) {
console.log(error);
}
});
primus.on('connection', function(spark) {
spark.on('data', function(data) {
spark.request.thesession.addthis = "save this to session";
spark.request.thesession.save();
});
});
}
module.exports = primus_start;