Sails.io.js WebSocket only works intermittently

Node version: 12.14.1 Sails version (sails): 1.2.4 ORM hook version (sails-hook-orm): 2.1.1 Sockets hook version (sails-hook-sockets): 2.0.0 Organics hook version (sails-hook-organics): N/A Grunt hook version (sails-hook-grunt): 3.1.0 Uploads hook version (sails-hook-uploads): N/A DB adapter & version (e.g. sails-mysql@5.55.5): sails-mysql@1.0.1 Skipper adapter & version (e.g. skipper-s3@5.55.5): N/A

Hi,

I have a sails.js application that uses websockets (sails.io) to communicate with a React application.

Most of the time, the socket fails to connect. The error in the React console on the frontend is:

WebSocket connection to 'ws:<URL>/socket.io/?__sails_io_sdk_version=1.2.1&__sails_io_sdk_platform=node&__sails_io_sdk_language=javascript&EIO=3&transport=websocket' failed: WebSocket is closed before the connection is established.
 ====================================
sails.io.js:420  The socket was unable to connect.
sails.io.js:420  The server may be offline, or the
sails.io.js:420  socket may have failed authorization
sails.io.js:420  based on its origin or other factors.
sails.io.js:420  You may want to check the values of
sails.io.js:420  `sails.config.sockets.onlyAllowOrigins`
sails.io.js:420  or (more rarely) `sails.config.sockets.beforeConnect`
sails.io.js:420  in your app.
sails.io.js:420  More info: https://sailsjs.com/config/sockets
sails.io.js:420  For help: https://sailsjs.com/support
sails.io.js:420  
sails.io.js:420  Technical details:
sails.io.js:420  Error: websocket error
    at WS.push../node_modules/engine.io-client/lib/transport.js.Transport.onError (transport.js:68)
    at WebSocket.ws.onerror (websocket.js:159)
    at WS.push../node_modules/engine.io-client/lib/transports/websocket.js.WS.doClose (websocket.js:244)
    at WS.push../node_modules/engine.io-client/lib/transport.js.Transport.close (transport.js:98)
    at Socket.push../node_modules/engine.io-client/lib/socket.js.Socket.onClose (socket.js:713)
    at close (socket.js:661)
    at Socket.push../node_modules/engine.io-client/lib/socket.js.Socket.close (socket.js:656)
    at manager.js:263

I have implemented a simple beforeConnect in the backend that looks like this:

  beforeConnect: function(handshake, proceed) {

    // Send back `true` to allow the socket to connect.
    // (Or send back `false` to reject the attempt.)
    console.log(handshake);
    console.log(proceed);
    return proceed(undefined, true);

  },

This should simply show the handshake and continue.

When the connection is successful, which is random and maybe happens 10% of the time, this works as expected and shows the handshake object. I then see that the frontend has connected in the console.

When it does not work, the beforeConnect function doesn't even seem to be called, so I'm not sure that the connection is even reaching the sails app. Since I set io.socket._raw.io._reconnection to true, it tries to reconnect, but again, the sails app doesn't seem to get the connection.

I should note that the same thing works both locally and in production on a cloud foundry service.

For more info, the front end code:

let socketIOClient = require('socket.io-client');
let sailsIOClient = require('sails.io.js');
let io = sailsIOClient(socketIOClient);

// This function is called when the app starts
const initSocket = () => {
    io.sails.url = currentURL; // Set the base URL for sockets
    io.socket._raw.io._reconnection = true;
}

const update = (data) => {
    let roomId = uuidv4();
    let request = {data: data, roomId: roomId};

    store.dispatch(Actions.updateStatus.reset());

    try {
        io.socket.post('/update', request, () => {
            toastr.info('Starting update');
        });

        io.socket.on('success', (success) => {
            store.dispatch(Actions.updateStatus.addSuccess(success.data));
        });

        io.socket.on('failure', (failure) => {
            store.dispatch(Actions.updateStatus.addFailure(failure.data));
        });

        io.socket.on('done', () => {
            io.socket.post('/finishUpdate', {roomId: roomId}, () => {
                toastr.info('Done updating');
                store.dispatch(Actions.updateStatus.signalComplete());
            })
        });
    } catch (err) {
        toastr.error('Socket Failure');
        return;
    }

}

Backend:

pdeUpdate: async function (req, res) {

    let data = req.body.data;
    let updatedBy = 'unknown';

    if (!req.isSocket) {
        sails.log.error('request was not a socket: ' + JSON.stringify(req));
        return res.badRequest();
    }

    var roomId = req.body.roomId;

    sails.sockets.join(req, roomId, function(err) {
        if (err) {
          return res.serverError(err);
        }

        return res.json({
          message: `Subscribed to ${roomId}`
        });
    });
    outerData:
    for (let item in data) {
        try {
            let result = await sails.sendNativeQuery('CALL update($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14);', [... (args here)]);
            if (typeof result.rows !== 'undefined') {
                if (typeof result.rows[0] !== 'undefined') {
                    for (let row in result.rows[0]) {
                        if (typeof result.rows[0][row]['@full_error'] !== 'undefined') {
                            sails.sockets.broadcast(roomId, 'failure', {result: 'failure', data: data[item].name});
                            continue outerData;
                        }
                    }
                }
            }
            if (typeof result !== 'undefined'){
                sails.sockets.broadcast(roomId, 'success', {result: 'success', data: data[item].name});
            }
        } catch (err) {
            sails.log.error('error on row ' + JSON.stringify(data[item]) + err);
            sails.sockets.broadcast(roomId, 'failure', {result: 'failure', data: data[item].name});
            continue;
        }
    }
    sails.sockets.broadcast(roomId, 'done', {message: 'done'});
},

finishUpdate: async function (req, res) {
    let roomId = req.body.roomId;

    sails.sockets.leave(req, roomId, function(err) {
        if (err) {
          return res.serverError(err);
        }

        return res.json({
          message: `done with ${roomId}`
        });
    });
}

@anthozep Thanks for posting! We'll take a look as soon as possible.

In the mean time, there are a few ways you can help speed things along:

look for a workaround. (Even if it's just temporary, sharing your solution can save someone else a lot of time and effort.)
tell us why this issue is important to you and your team. What are you trying to accomplish? (Submissions with a little bit of human context tend to be easier to understand and faster to resolve.)
make sure you've provided clear instructions on how to reproduce the bug from a clean install.
double-check that you've provided all of the requested version and dependency information. (Some of this info might seem irrelevant at first, like which database adapter you're using, but we ask that you include it anyway. Oftentimes an issue is caused by a confluence of unexpected factors, and it can save everybody a ton of time to know all the details up front.)
read the code of conduct.
if appropriate, ask your business to sponsor your issue. (Open source is our passion, and our core maintainers volunteer many of their nights and weekends working on Sails. But you only get so many nights and weekends in life, and stuff gets done a lot faster when you can work on it during normal daylight hours.)
let us know if you are using a 3rd party plugin; whether that's a database adapter, a non-standard view engine, or any other dependency maintained by someone other than our core team. (Besides the name of the 3rd party package, it helps to include the exact version you're using. If you're unsure, check out this list of all the core packages we maintain.)

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balderdashy / sails

Sails.io.js WebSocket only works intermittently #6994