title: How to route the user to the login page on every page request in ASP.NET Core 2.0
body: <p>I've done much Googling to find out the best way of doing this in ASP.NET Core 2.0 but not come to any clear conclusions. In previous versions of ASP.NET / MVC I could route the user to the login page by checking their session is authenticated. </p>
  
  <p>I'm looking for something similar in ASP.NET Core 2.0. I want to check the user is authenticated on every page request, and if not route them to the login page.</p>
  
  <p>How can I achieve this in ASP.NET Core 2?</p>