Held: ,

Back to Outline 04 - Ruby on Rails & Software as a Service. On to Outline 06 - Behavior-Driven Development.

Summary

We continue our exploration of Rails by reviewing the latest assignment.

Related Pages

• https://github.com/saasbook/hw-rails-intro
• https://github.com/saasbook/rottenpotatoes-rails-intro

Overview

• Adding a sort feature.
• Adding a filter feature.
• Adding persistence.
• Putting it all together.
• Morals from the assignment.

Administrivia

• 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.

Sorting the List of Movies

• Update the controller to take a "sort by" parameter.
  • app/controllers/movies_controller.rb
• Update the HTML (haml) to add include a link that sets the "sort by" parameter
  • app/views/movies/index.html.haml

Filtering the List of Movies

• Update the model to include the list of ratings.
  • app/models/movie.rb
• Update the controller to take a "filter by" parameter.
  • app/controllers/movies_controller.rb
• Update the HTML (haml) to add the fields as specified.
  • app/views/movies/index.html.haml

Remembering Settings (1)

This is the second half of filtering

• We need to keep track of the "sort by" parameter

Remembering Settings (2)

• We also need to add the "sort by" parameter to the session.
• We need to compare the session to the parameters.
  • If they are different, we should redirect

One Solution

Stolen from the SaaSbook folks.

app/models/movie.rb

class Movie < ActiveRecord::Base
  def self.all_ratings
    %w(G PG PG-13 NC-17 R)
  end
end

app/controllers/movies_controller

  def index
    sort = params[:sort] || session[:sort]
    case sort
    when 'title'
      ordering,@title_header = {:title => :asc}, 'hilite'
    when 'release_date'
      ordering,@date_header = {:release_date => :asc}, 'hilite'
    end
    @all_ratings = Movie.all_ratings
    @selected_ratings = params[:ratings] || session[:ratings] || {}

    if @selected_ratings == {}
      @selected_ratings = Hash[@all_ratings.map {|rating| [rating, rating]}]
    end

    if params[:sort] != session[:sort] or params[:ratings] != session[:ratings]
      session[:sort] = sort
      session[:ratings] = @selected_ratings
      redirect_to :sort => sort, :ratings => @selected_ratings and return
    end
    @movies = Movie.where(rating: @selected_ratings.keys).order(ordering)
  end

app/views/movies/index.html.haml

%h1 All Movies

= form_tag movies_path, :method => :get, :id => 'ratings_form' do
  = hidden_field_tag "title_sort", true if @title_header
  = hidden_field_tag ":release_date_sort", true if @date_header
  Include: 
  - @all_ratings.each do |rating|
    = rating
    = check_box_tag "ratings[#{rating}]", 1, @selected_ratings.include?(rating), :id => "ratings_#{rating}"
  = submit_tag 'Refresh', :id => 'ratings_submit'

%table#movies
  %thead
    %tr
      %th{:class => @title_header}= link_to 'Movie Title', movies_path(:sort => 'title', :ratings => @selected_ratings), :id => 'title_header'
      %th Rating
      %th{:class => @date_header}= link_to 'Release Date', movies_path(:sort => 'release_date', :ratings => @selected_ratings), :id => 'release_date_header'
      %th More Info
  %tbody
    - @movies.each do |movie|
      %tr
        %td= movie.title 
        %td= movie.rating
        %td= movie.release_date
        %td= link_to "More about #{movie.title}", movie_path(movie)

= link_to 'Add new movie', new_movie_path

Morals from the Assignment

• Very few changes to get lots of power.
• Most applications require that you master multiple languages.
• The Interweb is your friend.