Rails%203%20In%20Action

376 CHAPTER 13 Designing an API
Listing 13.23 app/controllers/api/v1/tickets_controller.rb
class Api::V1::TicketsController < Api::V1::BaseController
before_filter :find_project
private
def find_project
@project = Project.for(current_user).find(params[:project_id])
rescue ActiveRecord::RecordNotFound
error = { :error => "The project you were looking for" +
" could not be found."}
respond_with(error, :status => 404)
end
end
In the beginning, you set up the controller to inherit from Api::V1::BaseController
so that it inherits the basic behavior of your API. Then you tell it that this controller
responds to both JSON and XML. Finally, you define a before_filter :find_project
that will find a project, providing that the user is able to access it. If the user cannot
access it, then you respond_with a 404 error.
Underneath the before_filter in this controller, you need to define the index
action to return a list of tickets for your project. You can do that with the code shown
in the following listing.
Listing 13.24 app/controllers/api/v1/tickets_controller.rb
def index
respond_with(@project.tickets)
end
That feels like you’re getting too much for free, doesn’t it? Rails is handling a lot of the
actions here for you. When you run bin/rspec spec/api/v1/tickets_spec.rb specs
again, your tests will now pass because you’ve got the controller defined correctly:
2 examples, 0 failures
This is a great start to generating a tickets API, and now with the skills you’ve learned
a little earlier in this chapter you should be able to bash out the rest with little effort.
Rather than covering that old ground again, it’ll be left as an exercise for you.
Let’s run all the tests with rake spec to make sure you didn’t break anything:
54 examples, 0 failures, 19 pending
Nope, nothing broken there, which is awesome to see. Time for a commit:
git add .
git commit -m "Added beginnings of the V1 Tickets API"
git push
You should probably limit the number of tickets that are sent back through the API or,
even better, cache the result. You’ll see ways to do both of these things in chapter 15,
and then you can apply them to the API when you feel it’s right. For now, it would be