ERR_TOO_MANY_REDIRECTS when using connect-ensure-login for index

Question

I am using passport.js with a local strategy, I can restrict my routes using the ensureLoggedIn() method of connect-ensure-login.

app.use('/login', login);
app.use('/connect', Auth.ensureLoggedIn('/login'), connect);

However if I try to secure the homepage I get an ERR_TOO_MANY_REDIRECTS error and I am redirected to the login page:

app.use('/', Auth.ensureLoggedIn('/login'), index);

I have tried to debug why this is but the problem only seems to occur when securing the index. If I remove the check from the index route it works fine.

Can anyone spot where I'm going wrong or suggest an alternative method to connect-ensure-login?

My app.js

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var passport = require('passport');
var LocalStrategy = require('passport-local').Strategy;
var Auth = require('connect-ensure-login');
var oauth1 = require('passport-oauth1');
var session = require('express-session');
var mongoose = require('mongoose');

var dbconf = require('./config/database');
var dbUser = require('./models/user');

var index = require('./routes/index');
var login = require('./routes/login');
var logout = require('./routes/logout');
var connect = require('./routes/connect');
var disconnect = require('./routes/disconnect');

var app = express();

// Database connection
mongoose.connect(dbconf.uri);
mongoose.Promise = global.Promise;
var db = mongoose.connection;
db.on('error',console.error.bind(console,'MongoDB connection error:'));


// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));


// Setup passport
app.use(session({secret: "Koiasoidpoaksdpoao98as", resave: true, saveUninitialized: false}));
app.use(passport.initialize());
app.use(passport.session());

passport.use(new LocalStrategy({
  usernameField: 'email',
  passwordField: 'password'
  }, (email, password, done) => {
    dbUser.findOne({email: email}, (err, user) => {
      if (err) { return done(err)}
      if (!user) { return done(null, false); }
      if (!user.comparePassword(password)) { return done(null, false); }
      return done(null, user);
    });
  })
);

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

passport.deserializeUser(function(user, done) {
  dbUser.findById(user, (err, founduser) => {
    if (err) { return done(err);}
    done(null, founduser);

  });
});

// set user variables for user detail in global layout
app.use(function(req,res,next){
  let account = ((req.session || {}).etsy || {}).account;
  let etsyval = false;
  if (account) {
    etsyval = true;    
  }
  if (res.locals.connected) {
    res.locals.connected.etsy = etsyval;
  } else {
    res.locals.connected = {etsy: etsyval};
  }

  next();
})

app.use('/', Auth.ensureLoggedIn('/login'), index);
app.use('/logout', logout);
app.use('/login', login);
app.use('/connect', Auth.ensureLoggedIn('/login'), connect);
app.use('/disconnect', Auth.ensureLoggedIn('/login'), disconnect);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;

My login.js (route)

var express = require('express');
var router = express.Router();
var passport = require('passport');
router.get('/',(req, res, next) => {
    res.render('login', {title:'Login to use Overseer'});
});
router.post('/', passport.authenticate('local', {successReturnToOrRedirect: '/', failureRedirect: '/login'}), (req,res,next) => {
    if (req.body.remember) {
        req.session.cookie.maxAge = 30 * 24 * 60 * 60 * 1000; // Cookie expires after 30 days
    }
    else {
        req.session.cookie.expires = false; // Cookie expires at end of session
    }
    res.redirect('/');

});
module.exports = router;

Answer 1

When you do

app.use('/somepath', Auth.ensureLoggedIn('/login'));

the middleware is applied not only for /somepath exactly, but also for /somepath/any, /somepath/any/another etc.

Thus, the middleware mounted at / fires for every request. In your case, when a request is redirected to /login, the middleware fires and redirects to /login again causing infinite loop.

Possible solution would be to protect GET / specifically in routes/index.js:

router.get('/', Auth.ensureLoggedIn('/login'), (req, res) => ...);

or reoder you handlers so only protected routes are affected by the middleware:

app.use('/logout', logout);
app.use('/login', login);

// applies to all below
app.use(Auth.ensureLoggedIn('/login'));

app.use('/', index);
app.use('/connect', connect);
app.use('/disconnect', disconnect);