603466164219281420 #support-questions

[POST] /api/auth/session/refresh
11:25:19:59
2021-07-08T09:25:19.781Z    80afeb81-c13a-45ef-8272-d06132bda786    ERROR    Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client    at ServerResponse.setHeader (_http_outgoing.js:561:11)    at sendJson (/var/task/node_modules/next/dist/next-server/server/api-utils.js:37:5)    at ServerResponse.apiRes.json (/var/task/node_modules/next/dist/next-server/server/api-utils.js:6:297)    at handler (/var/task/main/.next/server/pages/api/order/cart.js:30:21)    at processTicksAndRejections (internal/process/task_queues.js:95:5) {  code: 'ERR_HTTP_HEADERS_SENT'}2021-07-08T09:25:19.784Z    80afeb81-c13a-45ef-8272-d06132bda786    ERROR    Uncaught Exception     {"errorType":"Error","errorMessage":"write after end","code":"ERR_STREAM_WRITE_AFTER_END","stack":["Error [ERR_STREAM_WRITE_AFTER_END]: write after end","    at writeAfterEnd (_http_outgoing.js:694:15)","    at ServerResponse.end (_http_outgoing.js:815:7)","    at sendError (/var/task/node_modules/next/dist/next-server/server/api-utils.js:62:129)","    at apiResolver (/var/task/node_modules/next/dist/next-server/server/api-utils.js:8:373)","    at processTicksAndRejections (internal/process/task_queues.js:95:5)","    at async Server.handleApiRequest (/var/task/node_modules/next/dist/next-server/server/next-server.js:66:462)","    at async Object.fn (/var/task/node_modules/next/dist/next-server/server/next-server.js:58:580)","    at async Router.execute (/var/task/node_modules/next/dist/next-server/server/router.js:25:67)","    at async Server.run (/var/task/node_modules/next/dist/next-server/server/next-server.js:68:1042)","    at async Server.handleRequest (/var/task/node_modules/next/dist/next-server/server/next-server.js:32:504)"]}Unknown application error occurred

07/08/2021, 10:35 AM

Ah ok.. it's a backend related error.

07/08/2021, 10:36 AM

Can I see your auth.js file on the backend? which uses the supertokens-node middleware?

gusfune

07/08/2021, 10:36 AM

Copy code

ts
import { NextApiRequest, NextApiResponse } from "next"
import NextCors from "nextjs-cors"
import { superTokensNextWrapper } from "supertokens-node/nextjs"
import { middleware, init, getAllCORSHeaders } from "supertokens-node"
import { backendConfig } from "../../../data/supertokens"

init(backendConfig())

export default async function superTokens(
  req: NextApiRequest,
  res: NextApiResponse
) {
  await NextCors(req, res, {
    methods: ["GET", "HEAD", "PUT", "PATCH", "POST", "DELETE"],
    origin: [/\.offscript\.io$/, /\.vercel\.app$/],
    credentials: true,
    allowedHeaders: ["content-type", ...getAllCORSHeaders()],
  })
  await superTokensNextWrapper(
    async (next) => {
      await middleware()(req, res, next)
    },
    req,
    res
  )
  if (!res.writableEnded) {
    res.status(404).send("Not found")
  }
}

07/08/2021, 10:36 AM

Seems right..

07/08/2021, 10:38 AM

did this happen after you updated one of the SDKs? If yes, which one?

gusfune

07/08/2021, 10:38 AM

I don't know for sure, we only got this error today, let me check on the logs

07/08/2021, 10:44 AM

alright.

gusfune

07/08/2021, 10:45 AM

Can't find when it started, probably yesterday when we rolled out some updates, I will dig more into this and get back soon. I guess it's when we fetch from the API method that's using a different way to verify session

07/08/2021, 10:46 AM

So that API may be returning a 401 which would trigger the frontend to call the refresh endpoint

07/08/2021, 10:47 AM

which might be a bug.. cause if it's a different way for session verification, then our refresh API shouldn't be called.

07/08/2021, 10:48 AM

But even if it's called, the above error shouldn't be happening either way.

gusfune

07/08/2021, 10:49 AM

Huh. Actually happens in firefox too, just leave the session stale long enough: https://offscript.io/henrietta-fromholtz/nividas-eyewear-kyoto-sandy-peach

gusfune

07/08/2021, 10:50 AM

(this is an example link that keeps refreshing)

07/08/2021, 10:59 AM

on this page, all calls to

/api

succeed.

07/08/2021, 11:02 AM

are you sure this issue is related to supertokens?

07/08/2021, 11:03 AM

Cause even if a supertokens' session doesn't exist, and the frontend isn't calling any of the APIs exposed via supertokens-node, it's still refreshing constantly.

gusfune

07/08/2021, 11:13 AM

This is on the back-end, but it seems we have this weird piece here:

Copy code

if (error.type === "TRY_REFRESH_TOKEN") {
      supertokens.errorHandler()(error, req, res, () => ({}))
    }

Does this errorHandler ping the front-end?

gusfune

07/08/2021, 11:13 AM

Checking this possibility as well

07/08/2021, 11:15 AM

where is this again?

gusfune

07/08/2021, 11:19 AM

in the method we use to make calls to the API, from the back-end

07/08/2021, 11:21 AM

So your backend makes calls to other APIs and forwards the session tokens and headers to that other API?

gusfune

07/08/2021, 11:23 AM

frontend -> calls

/api/something

-> calls our backeend method (has a check session because it has a behavior if the user is a guest) -> calls external api

07/08/2021, 11:24 AM

i see

07/08/2021, 11:25 AM

supertokens.errorHandler()(error, req, res, () => ({}))

will send a response to the client. So if you don't return from here and try and use

res

after, it will give you a response already send error.