Refactoring the workflow

We are going to add some scenarios to certificate_generation.feature

First a small re-factoring:

# features/certificate_generation.feature

...
# change Scenario title to:
Scenario: Generate certificates

# add step:
  And I should see 3 "view certificate" links

...

Add a new step definition to your application_steps.rb:

# features/step_definitions/application_steps.rb

...
And(/^I should see ([^"]*) "([^"]*)" links$/) do |count, element|
  expect(page).to have_link(element, count: count)
end
...

We only want the user to be able to generate certificates if no certificates have been generated, right? If we put that in a User Story, it could look something like this:

As a course administrator
In order to avoid duplicate certificates and validation links
I want to restrict the use of certificate generator to delivery
dates with no previously generated certificates.

In the certificate_generation.feature file, add the following scenario:

# features/certificate_generation.feature

...
Scenario: Certificate generation is disabled if certificates exists
  Given valid certificates exists
  Then I should not see "Generate certificates"

In order to get the Certificate model to validate, we want to slightly change the way we generate the pdf's. We are going to remove the after :create callback from that class:

# lib/certificate.rb

# delete:
  after :create do
    CertificateGenerator.generate(self)
  end

And add that command to our controller. Along with some other changes.

Let's update our controller method:

# lib/application.rb

...
get '/courses/generate/:id', auth: :user do
  @delivery = Delivery.get(params[:id])
  if !@delivery.certificates.find(delivery_id: @delivery.id).size.nil?
    session[:flash] = 'Certificates has already been generated'
  else
    @delivery.students.each do |student|
      cert = student.certificates.create(created_at: DateTime.now, delivery: @delivery)
      keys = CertificateGenerator.generate(cert)
      cert.update(certificate_key: keys[:certificate_key], image_key: keys[:image_key])
    end
    session[:flash] = "Generated #{@delivery.students.count} certificates"
  end
  redirect "/courses/delivery/show/#{@delivery.id}"
end
...

With this implementation we are:

1. Preventing unauthorized access to the route

2. Preventing certificates to be created if there already exists certificates for that course delivery

3. Creating a certificate for each student

4. Giving the user feedback on performed actions with a flash

We need to make an addition to the Delivery model - letting each Delivery know what Certificates are associated to it using whatever Certificates are associated to the Deliveries Students.

We start by writing a spec for that:

# spec/delivery_spec.rb

...
it { is_expected.to have_many_and_belong_to :certificates }
...

Then the implementation:

# lib/delivery.rb

...
has n, :certificates, through: :students
...

We also want to open this view for non logged in users but only allowing actions to be performed if a user is logged in. In that way, we do not need to create separate views for those contexts. Make sure you are not using the auth: :user method on the route to get that view:

# lib/application.rb

...
  get '/courses/delivery/show/:id' do
    @delivery = Delivery.get(params[:id].to_i)
    erb :'courses/deliveries/show'
  end
...

The next step will be to re-factor the view:

# lib/views/courses/deliveries/show.erb

<h2><%= @delivery.course.title %></h2>
<p>Course date: <%= @delivery.start_date %></p>

<% if @delivery.students.any? %>
  <div> Students:
    <ul>
      <% @delivery.students.each do |student| %>
        <li id="student-<%= student.id %>>"><%= [student.full_name, ''].join(' ') %>
          <% unless student.certificates.all(delivery_id: @delivery.id).empty? %>
            <%= link_to 'view certificate', student.certificates.first(delivery_id: @delivery.id).certificate_url, target: '_blank' %>
          <% end %>
        </li>
      <% end %>
    </ul>
    <% if current_user && @delivery.certificates.all(delivery_id: @delivery.id).empty? %>
      <div>
        <%= link_to 'Generate certificates', "/courses/generate/#{@delivery.id}", class: 'button' %>
      </div>
    <% end %>
  </div>
<% elsif current_user %>
  <% form_tag '/courses/deliveries/file_upload', method: :post, multipart: true do %>
    <%= hidden_field_tag :id, value: @delivery.id %>
    <%= file_field_tag :file %>
    <%= submit_tag 'Submit', class: 'button' %>
  <% end %>
<% end %>

This change is introducing several changes:

1. Generate certificates link will only be visible if a) there is a current_user AND no certificates has been generated (!@delivery.certificates.any?).

2. The upload data file interface (the form) is visible only if there is a current_user present and there are no students associated to the delivery.

3. On the students list, a link to the certificate is visible IF there is a certificate associated with that student.

4. We are displaying the delivery date.

5. We add class 'button' to links to give it look and feel of a button.

We want to be able to retrieve the files from S3 using a http request. For that we need to have access to a URL.

Add the following specs to your certificate_spec.rb

# spec/certificate_spec.rb


describe 'Creating a Certificate' do
...
  describe 'S3' do
    before { CertificateGenerator.generate(@certificate) }

    it 'can be fetched by #image_url' do
      expect(@certificate.image_url).to eq 'https://certz.s3.amazonaws.com/pdf/test/thomas_ochman_2015-01-01.jpg'
    end

    it 'can be fetched by #certificate_url' do
      expect(@certificate.certificate_url).to eq 'https://certz.s3.amazonaws.com/pdf/test/thomas_ochman_2015-01-01.pdf'
    end
  end
end

We know that the links to AWS are build in a specific way and we can use that to dynamically create our own urls. Add the following methods to your certificate.rb

# lib/certificate.rb

...
def image_url
  "https://#{ENV['S3_BUCKET']}.s3.amazonaws.com/#{self.image_key}"
end

def certificate_url
  "https://#{ENV['S3_BUCKET']}.s3.amazonaws.com/#{self.certificate_key}"
end

...

If you run all your tests, they should pass. However, our tests are not very extensive and there are many scenarios that we have failed to write coverage for. I would like you to take a few minutes and think about what else we should be testing for in Cucumber.