NodeJS + Express: How to secure a URL

Question

I am using latest versions of NodeJS and ExpressJS (for MVC).

I usually configure my rest paths like this, for example:

app.get('/archive', routes.archive);  

Now i want my /admin/* set of URLs to be secured, I mean I need just simple authentication, it's just a draft.

When a user tries to access, for example, /admin/posts, before sending him the corresponding view and data, I check for a req.session.authenticated. If it's not defined, I redirect to the login page.

Login page has a simple validation form, and a sign-in controller method: if user does send "right user" and "right password" I set the session variable and he's authenticated.

What I find difficult, or I don't understand, is how to actually make the "filter" code, I mean, the auth check, before every /admin/* path call.

Does this have something to do with "middleware" express functions?

Thank you

Solution 1

Yep, middleware is exactly what you want. A middleware function is just a function that works just like any other Express route handler, expept it gets run before your actual route handler. You could, for example, do something like this:

function requireLogin(req, res, next) {
  if (req.session.loggedIn) {
    next(); // allow the next route to run
  } else {
    // require the user to log in
    res.redirect("/login"); // or render a form, etc.
  }
}

// Automatically apply the `requireLogin` middleware to all
// routes starting with `/admin`
app.all("/admin/*", requireLogin, function(req, res, next) {
  next(); // if the middleware allowed us to get here,
          // just move on to the next route handler
});

app.get("/admin/posts", function(req, res) {
  // if we got here, the `app.all` call above has already
  // ensured that the user is logged in
});

You could specify requireLogin as a middleware to each of the routes you want to be protected, instead of using the app.all call with /admin/*, but doing it the way I show here ensures that you can't accidentally forget to add it to any page that starts with /admin.

Solution 2

A even simpler approach would be to add the following code in the App.js file.

var auth = function(req, res, next) {

    if(isAdmin) {

        return next();

    } else {

        return res.status(400)

    }
};

app.use('/admin', auth, apiDecrement);

As you can see the middleware is being attached to the route. Before ExpressJS goes forward, it executes the function that you passed as the second parameter.

With this solution you can make different checks before displaying the site to the end user.

Best.

Solution 3

Like brandon, but you can also go the connect route

app.use('/admin', requireLogin)
app.use(app.router)

app.get('/admin/posts', /* middleware */)