Lecture 307:- Passing User data to views and restricting page access

To pass user data to views and restrict page access, we can use middleware in Express. Middleware functions can be used to intercept requests before they reach the intended route handler.

We can define a middleware function that checks if the user is authenticated by checking for the presence of a user object in the request object. If the user is not authenticated, the middleware function can redirect the user to the login page.

Here's an example middleware function that can be used to restrict access to a route:

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function isAuthenticated(req, res, next) {  if (req.user) {    // User is authenticated, continue to next middleware    return next();  }  // User is not authenticated, redirect to login page  res.redirect('/login'); }

This middleware function checks if the req.user object is present. If it is, it means that the user is authenticated and the function calls next() to continue to the next middleware function or route handler.

If req.user is not present, it means that the user is not authenticated, and the function redirects the user to the login page using res.redirect('/login').

We can use this middleware function to restrict access to certain routes in our application by adding it as a parameter to the route definition:

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app.get('/dashboard', isAuthenticated, function(req, res) {  res.render('dashboard'); });

In this example, the isAuthenticated middleware function is added as the second parameter to the app.get() function. This means that the isAuthenticated middleware function will be called before the route handler function.

If the user is authenticated, the route handler function will be called, and the dashboard view will be rendered. If the user is not authenticated, the isAuthenticated middleware function will redirect the user to the login page before the route handler function is called.