Overview

• Preliminaries.
  • Admin.
• Thinking about adding features.
• Adding a sort feature.
• Adding a filter feature.
• Adding simple persistence.
• Adding complex persistence.
• Putting it all together.

Preliminaries

Admin

• We are continuing to hit transition problems. I'll do my best to help you work through them.
  • We'll work through the rest of HW2 in class today.
  • I have time reserved on Saturday to work through the new Chapter 7 examples (hopefully in advance of when you'll be doing them).
• We will be temporarily skipping over chapters 5 and 6 to move on to BDD.
  • Because we have a half-class, we may not come back to chapter 6.
• No matter what it says online, your next homework is at https://github.com/saasbook/hw-bdd-tdd-cycle.
  
  • When cloning, clone hw-bdd-tdd-cycle, not bdd-tdd-cycle.

Questions

Can we feel free to ignore the stupid things on the Web site?

Yes.

Will you ever fix the quizzes?

Maybe.

Thinking about adding features

• Remember: Rails uses MVC
• Every feature change suggests that you ask
  • Do I have to change the model? If so, how?
  • I probably have to change the controller. How?
  • Do I have to change the view? If so, how?
• How does the view communicate this to the controller?
  • Through the URL or the query string

Adding a sort feature

• Changes to the model?
  • Nope.
• Changes to the controller?
  • We'll need to change the part of the controller that makes the list of movies.
  • Was @movies = Movie.all
  • Replace by @movies = Movie.order(:title => :asc)
• Changes to the view?
  • Trigger in the view to set off the controller
    • Change the link %th{:class => title_header, :id => "Title"} = link_to "Movie Title", movies_path(:sort_by => 'title')
    • Generates <th class="..." id="Title"><a href="...">Movie Title</a></td>
  • Visual feedback as to the change
• Communicate changes
  • Different URL
  • params[:sort_by]

Adding a filter feature

• Changes to the model
  • The model needs to tell us what the valid ratings are class Movie < ActiveRecord::Base def self.all_ratings ["G", "PG", "PG-13", "NC-17", "R", "Z"] end end
• Changes to the controller
  • Get information from the view (params[:ratings])
  • Movie.where(rating: ...).order(...)
  • Communicate the valid ratings to the view @ratings = Movie.all_ratings
• Changes to the view
  • Add a way to select filtering criteria (in the assignment)
  • Add that to the queries we make (need to Google forms in haml)
  • Have the controller communicate back to us which of the ratings are selected

Adding persistence

Putting it all together