Automatically logging in the user after registration

In general, most web applications uses e-mail confirmations before allowing users to log in to the system. However, there can be certain scenarios where we need to automatically authenticate the user into the application. A social network sign-in is a great example for such a scenario. When using social network logins, the system checks whether the user is already registered. If not, the application automatically registers the user and authenticates them. We can easily modify our code to implement an automatic login after registration. Consider the following code:

    if ( !is_user_logged_in() ) { 
      wp_set_auth_cookie($user_id, false, is_ssl()); 
      include WPWAF_PLUGIN_DIR . 'templates/login-template.php'; 
      exit; 
    } 

The registration code is updated to use the wp_set_auth_cookie function. Once it's used, the user authentication cookie will be created and hence the user will be considered as automatically signed in. Then, we will redirect to the login page as usual. Since the user is already logged in using the authentication cookie, they will be redirected back to the home page with access to the backend. This is an easy way of automatically authenticating users into WordPress.