Unable to access session inside onProxyReqWs

Hello, I have issue: I want to use onProxyReqWs for authentication. I need to take my session data and send it to websocket server as a header. But my connect middlewares are not getting called before proxy in case of websocket connection. Here is example:

app.use((req, res, next) => {
  req.test = 123
})

app.use(proxy({
  changeOrigin: true,
   ws: true,
   target: 'http://localhost:7045',
    onProxyReq(proxyReq, req, res) {
        // Everything is correct, req.test are set here
        console.log('onProxyReq triggered: ', req.test)
        proxyReq.setHeader('x-secret', req.test);
    },
    onProxyReqWs(proxyReq, req, sock, options, head) {
        // Whoops, req.test are undefined!
        console.log('onProxyReqWs triggered: ', req.test)
    }
))

I don’t understand why and most importantly, HOW it bypasses middleware chain, since proxy is a middleware itself. Can you please explain this magic and advice me how to get session data from previous middlewares?

The problem is that I use it inside nuxt, which only supports low-level middlewares (e.g. only use()), so I cannot attach anything to connect app.

[CrazyPandar]

I have met the same problem. It seems if proxy for websocket, the HPM will overwrite previous express handler. let’s look at the code below:

const WsProxy = HPM(...);
DiskManager.use('/socket', function(req, res, next){
    console.log("entering first handler")
    next();
});
DiskManager.use('/socket', WsProxy);

If incoming request is websocket request, the “entering first handler” will not appear.

So weird!!! How can we solve this problem?

[mrtnbroder]

@MatthiasGrandl

My solution:

// configure express app however you like, then:
const server = app.listen(port)

const graphqlProxy = createProxyMiddleware({
  target: GRAPHQL_URI,
  changeOrigin: true,
  ws: true,
})

// Re-enable sessions on websockets. Middlewares are not passed to our websocket server and therefore our required `req.session` on the request is not available.
server.on("upgrade", (req, socket, head) => {
  // return a promise to make sure the session is added to the request
  // before anything else will be called.
  return new Promise((resolve) => {
    session(req, {} as any, () => {
      // req.session is now available and will be passed alongside the request
      graphqlProxy.upgrade?.(req, socket, head)
      resolve()
    })
  })
})

Hope this helps!