Rails%203%20In%20Action

378 CHAPTER 13 Designing an API
You can run these two commands to run this migration, and then you’ll be on your
way:
rake db:migrate
rake db:test:prepare
You can now write a test to make sure that the request count is going to be incremented
with each request. You’ll open a new file at spec/v1/api/rate_limit_spec.rb so that you
can separate these tests from the others, because they are not part of the projects API
or the errors from it. Into this file you’ll put the code from the following listing.
Listing 13.25 spec/v1/api/rate_limit_spec.rb
require 'spec_helper'
describe "rate limiting", :type => :api do
let(:user) { create_user! }
it "counts the user's requests" do
user.request_count.should eql(0)
get '/api/v1/projects.json', :token => user.authentication_token
user.reload
user.request_count.should eql(1)
end
end
When you run this spec now with bin/rspec spec/v1/api/rate_limit_spec.rb, it’s
going to fail on the final line because the request count hasn’t been incremented:
Failure/Error: user.request_count.should eql(1)
expected 1
got 0
(compared using eql?)
Alright, now that you’ve got a failing test, you can make it work! Open app/
controllers/api/v1/base_controller.rb and add in a new method called check_rate
_limit right underneath the current_user method, using this code:
def check_rate_limit
@current_user.increment!(:request_count)
end
By calling the increment! method on the user object, the field specified will be incremented
once. To call this method, you’ll put it as another before_filter underneath
the authenticate_user one at the top of this controller:
before_filter :check_rate_limit
That’s all there is to it, and so it will pass when you run bin/rspec spec/api/v1/
rate_limit_spec.rb:
1 example, 0 failures
This is splendid. Before you run any more specs or make any commits, you’ll do what
you came here to do: limit some rates.