core: fix socket.io endpoint path

[paul-marechal]

Socket.io will try to connect to domain.com/socket.io to establish
communication by default. This is problematic when the frontend is
served on an HTTP path that isn't /.

Update the path supplied to Socket.io to take the current location into
account.

How to test

• Build and run this PR on localhost:3000.
• Run the proxy script below like node index.js 4000 /random-string/ http://localhost:3000/
• Connect to localhost:4000/random-string/ with your browser. It should work.

package.json:

{
  "name": "http-proxy-test",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "dependencies": {
    "http-proxy": "^1.18.1"
  },
  "devDependencies": {
    "@types/http-proxy": "^1.17.8"
  }
}

index.js:

const http = require('http')
const httpProxy = require('http-proxy')

let [_node, _script, port, proxyPathPrefix, target] = process.argv

const proxy = httpProxy.createProxyServer({ ws: true, target })
http.createServer((req, res) => {
    if (req.url.startsWith(proxyPathPrefix)) {
        req.url = req.url.substring(proxyPathPrefix.length - 1)
        proxy.web(req, res, undefined, error => console.error(error))
    } else {
        res.statusCode = 404
        res.write(`404: ${req.url}`)
        res.end()
    }
}).on('upgrade', (req, socket, head) => {
    if (req.url.startsWith(proxyPathPrefix)) {
        req.url = req.url.substring(proxyPathPrefix.length - 1)
        proxy.ws(req, socket, head, undefined, error => console.error(error))
    } else {
        socket.end()
    }
}).listen(port)

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[msujew]

Thanks for taking care of this Paul, looking good!

Nevermind, I just noticed that it breaks on Electron. We should probably only run it when !isElectron?

[paul-marechal]

@msujew good catch, it should work on Electron now!

[msujew]

Working on both platforms now, thanks 👍