Cannot set headers after they are sent to the client/ Server crashes with this when page refreshes-CodePudding

Made a Question a few days ago on here, thought I had it figured out, even accepted the answer, because it was right regardless. but now I have the Same issue, same error.

Heres the Error.

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
    at ServerResponse.setHeader (_http_outgoing.js:558:11)
    at ServerResponse.header (/Users/apple/Documents/Web Dev/collab/Backend/node_modules/express/lib/response.js:771:10)
    at ServerResponse.send (/Users/apple/Documents/Web Dev/collab/Backend/node_modules/express/lib/response.js:170:12)
    at ServerResponse.json (/Users/apple/Documents/Web Dev/collab/Backend/node_modules/express/lib/response.js:267:15)
    at /Users/apple/Documents/Web Dev/collab/Backend/routes/index.js:90:23
    at processTicksAndRejections (internal/process/task_queues.js:93:5) {
  code: 'ERR_HTTP_HEADERS_SENT'
}

Heres Index.js. Line 90 is at the very bottom, @ router.get("/", isAuth, (req, res)

const router = require("express").Router();
const passport = require("passport");
const bodyParser = require("body-parser");
const genPassword = require("../lib/passwordUtils").genPassword;
const connection = require("../config/database");
const mongoose = require("mongoose");
const User = mongoose.models.User;
const isAuth = require("./authMiddleware").isAuth;
// cors is needed with router.use else you have to put routes on the app.js
const cors = require("cors");
router.use(cors({ origin: "http://localhost:3001", credentials: true }));
// const isAdmin = require("./authMiddleware").isAdmin;
router.use(bodyParser.urlencoded({ extended: false }));

/**
 * -------------- Post ROUTES ----------------
 *
 */

router.post("/login", (req, res, next) => {
  passport.authenticate("local", (err, user, info) => {
    if (err) {
      throw err;
    } else if (!user) {
      res.send("No User Exists");
    } else {
      req.logIn(user, (err) => {
        if (err) throw err;
        res.send(user);
        return;
        // console.log(req.user);
      });
    }
  })(req, res, next);
});

router.post("/register", (req, res) => {
  const saltHash = genPassword(req.body.repeatPassword);

  const salt = saltHash.salt;
  const hash = saltHash.hash;

  const newUser = new User({
    username: req.body.firstInput,
    fName: "",
    lName: "",
    title: "",
    hash: hash,
    salt: salt,
  });

  newUser.save().then((user) => {});
  res.sendStatus(200);
});

/**
 * -------------- GET ROUTES ----------------
 *
 */

router.post("/user", (req, res) => {
  const fName = req.body.firstInput;
  const lName = req.body.secondInput;

  const title = req.body.repeatPassword;

  const user = req.session.passport.user;
  User.updateOne(
    { _id: user },
    { fName: fName, lName: lName, title: title },
    function (err, result) {
      if (err) {
        res.sendStatus(401);
        console.log(err);
      } else {
        res.sendStatus(200);
      }
    }
  );
});
router.get("/", isAuth, (req, res) => {
  const userMap = {};
  User.find({}, function (err, users) {
    users.forEach(function (user) {
      userMap[user._id] = user;
    });
    return userMap;
  })
    .then((response) => {
      res.status(200).json({ user: req.user, auth: true, response });
      return;
    })
    .catch((err) => console.log(err));
});

module.exports = router;

Heres App.js

const express = require("express");
const app = express();
const mongoose = require("mongoose");
const session = require("express-session");
const passport = require("passport");
const crypto = require("crypto");
const routes = require("./routes");
const isAuth = require("./routes/authMiddleware").isAuth;
const connection = require("./config/database");
const cors = require("cors");
app.use(cors({ origin: "http://localhost:3001", credentials: true }));
const User = mongoose.models.User;

const bodyParser = require("body-parser");

const MongoStore = require("connect-mongo")(session);

require("dotenv").config();

app.use(express.json());
// app.use(bodyParser.urlencoded({ extended: false }));

app.use(express.urlencoded({ extended: true }));

const sessionStore = new MongoStore({
  mongooseConnection: mongoose.connection,
  collection: "sessions",
});

app.use(
  session({
    secret: "zdfbdaf",
    resave: true,
    saveUninitialized: true,
    store: sessionStore,
    cookie: {
      cookie: { secure: false },
      maxAge: 1000 * 60 * 60 * 24,
    },
  })
);

require("./config/passport");

app.use(passport.initialize());
app.use(passport.session());

app.use("/", routes);

app.listen(3000);

heres authMiddleware.js

module.exports.isAuth = (req, res, next) => {
  if (req.isAuthenticated()) {
    next();
    // res.status(200).json({ user: req.user, auth: true });
  } else {
    res.status(401).json({ auth: false });
  }
};

// module.exports.isAdmin = (req, res, next) => {
//     if (req.isAuthenticated() && req.user.admin) {
//         next();
//     } else {
//         res.status(401).json({ msg: 'You are not authorized to view this resource because you are not an admin.' });
//     }
// }

Heres passport.js

const passport = require("passport");
const LocalStrategy = require("passport-local").Strategy;
const connection = require("./database");
const mongoose = require("mongoose");
const User = mongoose.models.User;
const validPassword = require("../lib/passwordUtils").validPassword;
const cors = require("cors");
passport.use(cors({ origin: "http://localhost:3001" }));

const customFields = {
  usernameField: "username",
  passwordField: "password",
};

passport.use(
  new LocalStrategy(customFields, (username, password, done) => {
    User.findOne({ username: username })
      .then((user) => {
        if (!user) {
          console.log("No user");
          return done(null, false);
        } else {
          const isValid = validPassword(password, user.hash, user.salt);
          if (isValid) {
            console.log("Logged in");

            return done(null, user);
          } else {
            console.log("Wrong Password");
            return done(null, true);
          }
        }
      })
      .catch((err) => {
        done(err);
      });
  })
);

passport.serializeUser((user, done) => {
  done(null, user.id);
});

passport.deserializeUser((id, done) => {
  User.findById(id, (err, user) => {
    done(err, user);
  })
    .then((user) => {
      done(null, user);
    })
    .catch((err) => done(err));
});

It only crashes half the time, kind of? It works at first, until you refresh the page. I am at a loss. Had someone in the discord also not know the issue. I'm begging for some help here. I'm losing my mind.

CodePudding user response：

its because you are calling done twice once after finding the user and second after .then block in passport.deserializeUser function

this will work:

passport.deserializeUser((id, done) => {
  User.findById(id, (err, user) => {
      done(err, user)   
  });
});