Issue with Express and middleware - node.js

function redit (req, res, next) {
var session = req.session.user;
if (session) {
res.redirect('/home');
next();
}
else {
res.redirect('/');
next();
}
}
app.get('/', redit, function (req, res){
res.render('home0.ejs');
});
I code this middleware to check if there's a req.session.user, if there is, the user would be redirected to home, if not, would be redirected to /. But when this middleware is called, Chrome says to me Error 310 (net::ERR_TOO_MANY_REDIRECTS)', any solutions...?

You miss the fact that after redirect an anonymous user (with falsy req.session.user value) will end up at the same (/) page - so their identity will be checked up by redir middleware again... and again... and again. Hence the 'TOO MANY REDIRECTS' error.
The common solution is to redirect all the anonymouses to some other gateway page - and that page obviously should NOT check session.user.

Related

Nodejs express res.redirect loop

Using Nodejs and an Express server I'm trying to prevent anyone from reaching my second set of routes without logging in and while this works I get stuck in a redirect loop if the session doesn't detect the email in the session token. I believe its trying to check for the req.session.email for the /users endpoint as well causing the redirect loop but as the session checking middleware is used after I thought the /users endpoints would avoid the check.
How can I organize my code so that the books endpoints can only be reached when the req.session.email is satisfied and also not get stuck in a redirect loop when someone tries to reach it without being logged in?
app.use('/users', users)
app.use((req, res, next) => {
if(!req.session.email){
res.redirect('/login')
}
else{
next();
}
})
app.use('/books', books);
The order of the app.use statements is not really important in this case; You could add your middleware to the route-level if you're only checking the /books endpoint.
const yourMiddlewareFunction = (req, res, next) => {
if(!req.session.email){
res.redirect('/login')
}
else{
next();
}
}
app.use('/books', yourMiddlewareFunction, books);
If you only want to protect the /books endpoints, you can do it like this :
function requireLogin(req, res, next) {
if(!req.session.email){
res.redirect('/login')
}
else{
next();
}
}
app.use('/books', requireLogin, books);

Node Express - redirect to login view

I am trying to configure my express application to redirect to a login page based on some logic. I have the following:
app.use('/', function(req, res, next){
if(!req.session.accessToken){
//do something here
}
next();
});
I have a login.html file located in the root of the directory my application is being served from, I am just unsure what I need to call on the res object e.g. redirect, send
Also, I know the above will actually cause an infinite loop.
What's the correct approach here?
You'll want to be careful of your handler order, what you want (if you really want to do this on your own and not use something like Passport) is something like (the somewhat skeleton);
app.use('/login', function(req, res) { // Allows access to login page
res.send('displaying login page'); // before access token check
});
app.use(function(req, res, next) { // Catches access to all other pages
if(!req.session.accessToken) { // requiring a valid access token
res.redirect('/login');
} else {
next();
}
});
// the rest of your routes go here, they should not be called unless authenticated
The most obvious answer is to simply call res.redirect('/login.html'), but that would return a 301 (moved permanently) code to the browser. A more semantically correct solution might be to return a 401 (unauthorized) and render the login.html file to the response.
See Is it possible to send a 401 Unauthorized AND redirect (with a Location)?
So a solution might look something like this:
app.use('/', function(req, res, next){
if(!req.session.accessToken)
res.status(401).sendFile(path.join(__dirname+'/login.html'));
else
next()
});

Node.js / Express - Not rendering 503 Page on redirect

I'm trying to add a configuration value that allows us to take down the site temporarily when needed. It works, but for some reason it is not rendering the error page I've defined in my 503 route. I'm seeing "Service Unavailable. Redirecting to /503", but it doesn't ever redirect and doesn't display the page. Can anyone tell me what I'm missing here?
Middleware:
// Maintenance mode
app.use(function (req, res, next) {
if (config.globals.maintenanceModeEnabled) {
// Need this condition to avoid redirect loop
if (req.url !== '/503') {
res.redirect(503, '/503');
} else {
next();
}
} else {
next();
}
});
Route:
// Down for maintenance page
router.get('/503', function (req, res) {
res.status(503).render('common/503', {layout: 'base'});
});

Block regular users from Google auth callback Express Route

I have the following program to log in with Google:
app.get('/oauth/google', function(req, res) {
res.redirect(<OAUTH2_URL>);
});
app.get('/oauth/google/callback', function(req, res, next) {
var code = req.query.code;
if(!code || !_.isString(code)) {
return next(new Error(400, 'Invalid code'));
}
.
.
.
// I try the code to see if it is valid.
});
How do I only allow Googles redirect back to the application to have access to the callback route, and block regular users from using it?
If you're using sessions then you could set a flag from your /oauth/google path before you redirect off to Google, and then on your /oauth/google/callback simply check for that flag, and reset.
app.get('/oauth/google', function(req, res) {
req.session.authFlag = true;
res.redirect(<OAUTH2_URL>);
});
app.get('/oauth/google/callback', function(req, res, next) {
if (!req.session.authFlag) return next(new Error(403, 'Forbidden'));
else req.session.authFlag = false;
...
});
If you're not using sessions though, or for some reason sessions aren't available because the client doesn't support cookies (which should be a concern in above mentioned solution as well!), then I guess your best bet is to just check for req.query.code because other than that query string (req.query.code) there's no difference between requests redirected by Google and direct requests made by regular user.
(...req.headers.referer/origin could've worked in theory but they're unreliable and shouldn't be used as a measure)

Custom returnUrl on Node.js Passport's Google strategy

I'm using Express and Passport OpenID Google strategy and I would like to set returnURL on each auth request to be able to return to the page that initiated that auth.
The situation is that I have HTML5 slides application with Node.js backend (and with social stuff and editor and Portal and extensions... https://github.com/bubersson/humla) and I want be able to log in user on some slide (via slide menu...) but then I want him to get back to same slide easily.
So I would need something like this?
app.get('/auth/google', function(req,res) {
var cust = "http://localhost:1338/"+req.params.xxx;
passport.authenticate('google', returnURL:cust, function ...
}
I've read Passport's guide, but still don't know how to do that. I know this wouldn't be safe, but how else could I do it?
Or how can I make the application to return to the page from where the login has been initiated? Or is there a way to make OpenID authentication using AJAX (and still be able to use passport as well)?
I've figured this out for my apps Twitter authentication, I am sure that the GoogleStrategy is quite similar. Try a variant of this:
Assuming you have defined the route for the callback from the authentication service like so (from the passport guide):
app.get('/auth/twitter/callback',
passport.authenticate('twitter', {
successRedirect: authenticationRedirect(req, '/account')
, failureRedirect: '/'
})
);
Just change that block to this:
app.get('/auth/twitter/callback', function(req, res, next){
passport.authenticate('twitter', function(err, user, info){
// This is the default destination upon successful login.
var redirectUrl = '/account';
if (err) { return next(err); }
if (!user) { return res.redirect('/'); }
// If we have previously stored a redirectUrl, use that,
// otherwise, use the default.
if (req.session.redirectUrl) {
redirectUrl = req.session.redirectUrl;
req.session.redirectUrl = null;
}
req.logIn(user, function(err){
if (err) { return next(err); }
});
res.redirect(redirectUrl);
})(req, res, next);
});
Now, define your middleware for authenticated routes to store the original URL in the session like this:
ensureAuthenticated = function (req, res, next) {
if (req.isAuthenticated()) { return next(); }
// If the user is not authenticated, then we will start the authentication
// process. Before we do, let's store this originally requested URL in the
// session so we know where to return the user later.
req.session.redirectUrl = req.url;
// Resume normal authentication...
logger.info('User is not authenticated.');
req.flash("warn", "You must be logged-in to do that.");
res.redirect('/');
}
Works!
Wherever you have your login button, append the request's current URL as a
query parameter (adjust for whatever templating system you use):
<a href='/auth/google?redirect=<%= req.url %>'>Log In</a>
Then, add middleware to your GET /auth/google handler that stores this value in
req.session:
app.get('/auth/google', function(req, res, next) {
req.session.redirect = req.query.redirect;
next();
}, passport.authenticate('google'));
Finally, in your callback handler, redirect to the URL stored in the session:
app.get('/auth/google/callback', passport.authenticate('google',
failureRedirect: '/'
), function (req, res) {
res.redirect(req.session.redirect || '/');
delete req.session.redirect;
});
Try res.redirect('back'); in the callback for passport.authenticate
According to the author this isn't possible with OpenID strategies. We managed to update these dynamically by directly accessing the variables:
app.get('/auth/google', function(req, res, next) {
passport._strategies['google']._relyingParty.returnUrl = 'http://localhost:3000/test';
passport._strategies['google']._relyingParty.realm = 'http://localhost:3000';
passport.authenticate('google')(req, res, next);
});

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