We have a route set up that says GET requests for /pages should go to the pages

controller index method but that controller doesn't exist yet.

So the request is failing.

Let's create a controller to handle requests for page resources.

We can do that using a Rails generator.

Just as there is a scaffold generator and

a migration generator, there's also a controller generator.

So in our terminal, we need to cancel out of the Rails Server if it's running,

and then we type bin/rails generate controller.

And then the name of the controller we want to generate.

The name of the controller should be the plural form of your resource.

So since this is for page resources, the plural is pages.

Whatever you do, don't type controller on the end of the controller name.

If you do, you'll wind up with a file name pages_controller_controller.

And you don't want that.

If you ever make a mistake like that, here's a handy way to undo it.

Run the same command but replace generate with destroy.

That will automatically delete all the misnamed files.

Obviously the destroy subcommand is a little dangerous.

So don't use it if you've manually added code to any of those files.

Now let's rerun our generate command with the correct resource name, pages.

That will automatically generate a pages_controller.rb file in your

app/controllers subdirectory, along with our app's other controllers.

The word controller will automatically be added onto the name for you.

If we look at that file in our editor we see that it just defines an empty class

named PagesController that inherits from another class named ApplicationController.

There aren't any action methods defined yet, but

now that the controller exists, let's try our request again and see what happens.

We'll launch our server with bin/rails s.

Then we'll go back to the browser and reload the page.

The uninitialized constant PagesController error goes away.

Instead we see an unknown action error, the action index could not be found for

PagesController.

Let's add that index action method now.

In your editor, add def index, end and then save your changes.

There's no need to restart Rails, it will load our changes automatically.

Now let's go back to our browser and hit refresh and the route is complete.

Rails finds the index method it was trying to route to, so

the unknown action error goes away.

Now there's yet another error, though.

PagesController#index is missing a template.

Our request is being routed to a controller action, but

we're missing a view.

We'll fix that next.