How to share sessions with Socket.IO 1.x and Express 4.x?

express, node.js, session, socket.io

Solution

The solution is surprisingly simple. It's just not very well documented. It is possible to use the express session middleware as a Socket.IO middleware too with a small adapter like this:

sio.use(function(socket, next) {
    sessionMiddleware(socket.request, socket.request.res, next);
});

Here's a full example with express 4.x, Socket.IO 1.x and Redis:

var express = require("express");
var Server = require("http").Server;
var session = require("express-session");
var RedisStore = require("connect-redis")(session);

var app = express();
var server = Server(app);
var sio = require("socket.io")(server);

var sessionMiddleware = session({
    store: new RedisStore({}), // XXX redis server config
    secret: "keyboard cat",
});

sio.use(function(socket, next) {
    sessionMiddleware(socket.request, socket.request.res || {}, next);
});

app.use(sessionMiddleware);

app.get("/", function(req, res){
    req.session // Session object in a normal request
});

sio.sockets.on("connection", function(socket) {
  socket.request.session // Now it's available from Socket.IO sockets too! Win!
});


server.listen(8080);

Problem

How can I share a session with Socket.io 1.0 and Express 4.x? I use a Redis Store, but I believe it should not matter. I know I have to use a middleware to look at cookies and fetch session, but don't know how. I searched but could not find any working ``` var RedisStore = connectRedis(expressSession); var session = expressSession({ store: new RedisStore({ client: redisClient }), secret: mysecret, saveUninitialized: true, resave: true }); app.use(session); io.use(function(socket, next) { var handshake = socket.handshake; if (handshake.headers.cookie) { var str = handshake.headers.cookie; next(); } else { next(new Error('Missing Cookies')); } }); ```

Original source

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