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

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

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So the request is failing.

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

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We can do that using a Rails generator.

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Just as there is a scaffold generator and

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

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

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and then we type bin/rails
generate controller.

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

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

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

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

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

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And you don't want that.

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

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Run the same command but
replace generate with destroy.

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That will automatically delete
all the misnamed files.

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Obviously the destroy subcommand
is a little dangerous.

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

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

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That will automatically generate
a pages_controller.rb file in your

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

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

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

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named PagesController that inherits from
another class named ApplicationController.

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There aren't any action
methods defined yet, but

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

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

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

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The uninitialized constant
PagesController error goes away.

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

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PagesController.

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Let's add that index action method now.

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

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

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

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

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the unknown action error goes away.

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Now there's yet another error, though.

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PagesController#index is
missing a template.

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Our request is being routed
to a controller action, but

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we're missing a view.

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We'll fix that next.