Problem after updating from 2.0.2 to 2.0.3 with middleware

[ghost]

This error occurred the first time after updating from 2.0.2 to 2.0.3 - I really can't figure it out right now.

/data/project/app/node_modules/on-headers/index.js:25
	throw new TypeError('argument res is required')
	^

TypeError: argument res is required
	at onHeaders (/data/project/app/node_modules/on-headers/index.js:25:11)
	at session (/data/project/app/node_modules/express-session/index.js:219:5)
	at Array.<anonymous> (/data/project/app/modules/webserver.js:41:5)
	at run (/data/project/app/node_modules/socket.io/lib/namespace.js:123:11)
	at Namespace.run (/data/project/app/node_modules/socket.io/lib/namespace.js:135:3)
	at Namespace.add (/data/project/app/node_modules/socket.io/lib/namespace.js:163:8)
	at Client.connect (/data/project/app/node_modules/socket.io/lib/client.js:76:20)
	at Server.onconnection (/data/project/app/node_modules/socket.io/lib/index.js:398:10)
	at emitOne (events.js:115:13)
	at Server.emit (events.js:210:7)
error: Forever detected script exited with code: 1
error: Script restart attempt #63

const session = require('express-session');
[..]
const httpsServer = https.createServer(credentials, app).listen(config.server.port);
const io = require('socket.io')(httpsServer);

var sessionMiddleware = session({
    store: new RedisStore({}),
    secret: 'MYSECRET',
    resave: false,
    saveUninitialized: true
});

io.use(function (socket, next) {
    sessionMiddleware(socket.request, socket.request.res, next); //(/data/project/app/modules/webserver.js:41:5)
});

[darrachequesne]

@gindu as usual, could you please provide a way to reproduce?

Fiddle here: https://github.com/darrachequesne/socket.io-fiddle/tree/issues-2971

[ghost]

Only happening once (3hours after updating to 2.0.3 on live site) - reverting directly to 2.0.2.

On dev site i can't even reproduce it. So it will be hard to do this in a fiddle.

As of the error the "socket.request.res" was probably undefined/null ?

io.use(function (socket, next) {
    if(!socket) {
        console.log("#1: it happend again! " + util.inspect(socket));
        return next();
    }

    if(!socket && !socket.request) {
        console.log("#2: it happend again! " + util.inspect(socket.request));
        return next();
    }
    if(!socket && !socket.request && !socket.request.res) {

        console.log("#3: it happend again! " + util.inspect(socket.request.res));
        return next();
    }


    sessionMiddleware(socket.request, socket.request.res, next);
});

would this work without crashing the live site?

[ashnamuh]

I have a same issue

[ToddAlvord]

I found that this works.
sessionMiddleware( socket.request, {}, next );

You will have access to your session via socket.request.session. The res part is used to notify the session handler to check if it should save the session data or not after a request has completed. I never could get session data to save automatically with socket.io, even in v1. If you need to make changes to your session in a socket.io connection you can use socket.request.session.save(). Basically remove the res part as it wasn't being used anyways by socket.io. At least not in a way that seems to have any affect.

[ghost]

I found the issue for the crash. On polling socket.request.res is find. On Websocket it's undefined.

I have already swapped to express-socket.io-session module. This working without any issue

[evancarter-iex]

@darrachequesne Any possibility on getting a fix on this? We are seeing the same issue

[yaneony]

2.0.4 same issue.

[knoxcard]

@ToddAlvord - Todd, you're a lifesaver for that one!

[akontsevich]

Thanks, @ghost! Think we may consider to use express-socket.io-session module as an option. sessionMiddleware worked fine for me

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

with web socket.io-client <=> socket.io node.js server until I added socket.io-client-cpp application to the chain - crashed on socket.io-client-cpp connection with above error:

TypeError: argument res is required

[akontsevich]

@ToddAlvord thanks for the solution! Think it could be improved a little:

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

[dimified]

Thanks! Works for me.

[darrachequesne]

For future readers, the documentation was added here: https://socket.io/docs/v3/middlewares/#Compatibility-with-Express-middleware