1. Lecture 8 Software as a Service (SaaS )
CSCE 740 Software Engineering
Lecture 8 Software as a Service (SaaS )
Topics
SaaS
Readings: SaaS book Ch 2
February

2. Ruby; Rails; Cucumber; Capybara; Rspec; : Next Time: x
Last Time
Chapter 16 Software Reuse
New SaaS
edX/169 site:
Courseware: Lectures for each week; HW
Discussion: Blog for each week
Wiki: YouTube videos
Tutorials and Resources; Syllabus: textbook & VM; Progress
SaaS Software
Ruby; Rails; Cucumber; Capybara; Rspec; :
Next Time: x

3. CS 169.1 Lecture Schedule EdX

4. HW 2 – Rails – Rotten Potatoes
git clone git://github.com/saasbook/hw2_rottenpotatoes.git
bundle install --without production
rake db:migrate
rake db:seed
rails server
Create a free Heroku.com ( account
Name rottenpotatoes will be taken already
heroku run rake db:migrate
heroku run rake db:seed

5. Software as a Service SaaS
client-server
three-tier architecture
Design Patterns
Model View Controller
Model deals with app’s resources:e.g. users, movies,…
Controllers map broweser actions to application code
SaaS book – Chapter 2

6. Ruby with Rails Rails uses Active Record pattern for models
because it maps well to relational databases
For views Rails uses the Template View pattern
For Controllers Rails follows the Represntational State transfer (REST) principle
each controller action describes a single self-contained operation on one of the application’s resources
Modern SaaS frameworks such as rails capture developer experience by supporting SaaS design patterns
SaaS book – Chapter 2

7. Rails
Rails is a web application development framework in Ruby The Rails philosophy includes several guiding principles: DRY – “Don’t Repeat Yourself” – suggests that writing the same code over and over again is a bad thing. Convention Over Configuration – means that Rails makes assumptions about what you want to do and how you’re going to do it, rather than requiring you to specify every little thing through endless configuration files. REST (Representational State Transfer) is the best pattern for web applications

8. 2.1 100,000 Feet: Client-Server Architecture
to Appendix A and get this book’s “bookware” running on your own computer or in the cloud. Screencast shows how to deploy and login to your Virtual Machine and try an interaction with the simple educational app RottenPotatoes,
SaaS book – Chapter 2

9. SaaS book – Chapter 2

10. Design Patterns “design pattern—
a reusable structure, behavior, strategy, or technique
that captures a proven solution to a collection of similar problems
by separating the things that change from those that stay the same”
Examples:
client-server
model-view-controller
Design Patterns book – GoF (Gang Of Four)
SaaS book – Chapter 2

11. SaaS Summary
“SaaS Web apps are examples of the client-server architectural pattern,
client sending requests to the server on the user’s behalf,
and the server software is specialized for handling large volumes of such requests.
Because Web apps use open standards that anyone can implement royalty-free, the Web browser has become the “universal client.”
An alternative to client-server is peer-to-peer, in which all entities act as both clients and servers. While arguably more flexible, this architecture makes it difficult to specialize the software to do either job really well”
SaaS book – Chapter 2

12. 2.2 50,000 Feet: Communication—HTTP and URIs
Network protocol – “set of communication rules on which agents participating in a network agree”
HTTP –
TCP/IP –
IP address –
Domain Name System (DNS) protocol on top of TCP/IP
hostname to IP address mapping
 ???.???
local host
SaaS book – Chapter 2

13. Port Numbers
Port numbers from 1 to to distinguish servers at the same IP address.
80 webserver
22 ssh
443 https
The IANA. The Internet Assigned Numbers Authority assigns official default port numbers for various protocols and manages the top-level or “root” zone of DNS. .
SaaS book – Chapter 2

14. URIs versus URLs
A Uniform Resource Identifier (URI) names a resource available on the Internet. The interpretation of the resource name varies from application to application.
SaaS book – Chapter 2

15. HTTP cookies
HTTP cookies associate a particular user’s browser with information held at the server corresponding to that user’s session
it is the browser’s responsibility, not HTTP’s or the SaaS app’s, to make sure the right cookies are included with each HTTP request.
Stateless protocols therefore simplify server design at the expense of application design,
but happily, successful frameworks such as Rails shield you from much of this complexity.
SaaS book – Chapter 2

16. 2.3 10,000 Feet: Representation—HTML and CSS
Screencast 2.3.1: HTML Introduction Screencast 2.3.2: Inspecting the ID and Class attributes CSS uses selector notations Screencast 2.3.3: Introduction to CSS
SaaS book – Chapter 2

17. The MVC Architecture
“Model–View–Controller (MVC) is an architecture that separates the representation of information from the user's interaction with it” Models – represent the data Views – the User Interface Controllers – the “glue” between models and views

18. The Components of Rails
Action Pack
Action Controller - manages the controllers in Rails apps
Action Dispatch - handles routing of web requests
Action View - manages the view in Rails apps
Action Mailer - a framework for building services
Active Model - interface between the Action Pack gem services and Object Relationship Mapping gems such as Active Record
Active Record - base for the models in a Rails Apps
Active Resource - framework for connection between business objects and web services
Active Support
Railties

19. Representational State Transfer (REST)
Roy Fielding’s doctoral thesis, Architectural Styles and the Design of Network-based Software Architectures
“REST in terms of Rails boils down to two main principles:
Using resource identifiers such as URLs to represent resources.
Transferring representations of the state of that resource between system components”

20. Creating a New Rails Project
# gem install rails $ rails –version $ rails new blog $ rails new –h Usage: rails new APP_PATH [options] … $ cd blog

21. Rails Application Directory
File/Folder
Purpose
app/
Contains the controllers, models, views and assets for your appl
config/
Configure your application’s runtime rules, routes, database, and
config.ru
Rack configuration for Rack based servers used to start the appl
db/
Contains your current database schema, and db migrations.
doc/
In-depth documentation for your application.
Gemfile Gemfile.lock
These files allow you to specify what gem dependencies are needed for your Rails application.
lib/
Extended modules for your application.
log/
Application log files.
public/
Contains the static files and compiled assets.

22. Rails Application Directory (continued)
README.rdoc
This is a brief instruction manual for your application. You should edit this file to tell others what your application does, how to set it up, and so on.
script/
Contains the rails script that starts your app and can contain other scripts you use to deploy or run your application.
test/
Unit tests, fixtures, and other test apparatus. These are covered in Testing Rails Applications
tmp/
Temporary files
vendor/
A place for all third-party code. In a typical Rails application, this includes Ruby Gems, the Rails source code (if you optionally install it into your project) and plugins containing additional prepackaged functionality.
Rakefile
This file locates and loads tasks that can be run from the command line. The task definitions are defined throughout the components of Rails. Rather than changing Rakefile, you should add your own tasks by adding files to the lib/tasks directory of your application.

23. Rails Application Directory: app
This is your application, it contains:
assets - images javascripts stylesheets
controllers -
application_controller.rb
movies_controller.rb
helpers application_helper.rb movies_helper.rb
mailers
models - movie.rb
Views –
layouts: application.html.haml
movies: edit.html.haml index.html.haml new.html.haml show.html.haml

24. HAML – a lightweight Markup Language
“used to describe the XHTML of any web document without the use of traditional inline coding” “Haml functions as a replacement for inline page templating systems such as PHP, RHTML, and ASP”

25. YAML
YAML (rhymes with camel) is a human-readable data serialization format
YAML is a recursive acronym for
"YAML Ain't Markup Language”
emphacizing data-orientation over document mark-up
--- receipt: Oz-Ware Purchase Invoice
date:
customer:
given: Dorothy
family: Gale
items:
- part_no: A4786
descrip: Water Bucket (Filled)
price: 1.47
quantity: 4
- part_no: E1628
descrip: High Heeled "Ruby" Slippers
size: 8
price:
quantity: 1

26. Configuring a Database
Environments
Development
Test - automated tests
Production
config/database.yml
development:
  adapter: sqlite3
  database: db/development.sqlite3
  pool: 5
  timeout: 5000

27. Creating the Database
rake db:create // Rake is a general-purpose command-runner
rake –T
rake about # List versions of all Rails frameworks and the env...
rake assets:clean # Remove compiled assets
rake assets:precompile # Compile all the assets named in config.assets.pre...
rake cucumber # cucumber rake task not available (cucumber not in...
rake db:create # Create the database from config/database.yml for ...
rake db:drop # Drops the database for the current Rails.env (use...
rake db:fixtures:load # Load fixtures into the current environment's data...
rake db:migrate # Migrate the database (options: VERSION=x, VERBOSE...
rake db:migrate:status # Display status of migrations …

28. Starting up the Web Server
$rails server //starts instance of the WEBrick web server Set browser to “Welcome Aboard page”

29. rails generate rails generate controller home index rails generate
Usage: rails generate GENERATOR [args] [options]
General options:
-h, [--help] # Print generator's options and usage
-p, [--pretend] # Run but do not make any changes
-f, [--force] # Overwrite files that already exist …

30. Setting the Application Home Page
Edit in text editor
<h1>Hello, Rails!</h1>
$ rm public/index.html
Open the file config/routes.rb
Blog::Application.routes.draw do
  #...
  # You can have the root of your site routed with "root"
  # just remember to delete public/index.html.
  root :to => "home#index"
The root :to => "home#index" tells Rails to map the root action to the home controller’s index action.

31. Getting Up and Running Quickly with Scaffolding
Creating a Resource $ rails generate scaffold Post name:str title:str content:text
File
Purpose
db/migrate/ _create_posts.rb
Migration to create the posts table in db
app/models/post.rb
The Post model
test/unit/post_test.rb
Unit testing harness for the posts model
test/fixtures/posts.yml
Sample posts for use in testing
config/routes.rb
Edited to include routing info for posts
app/controllers/posts_controller.rb
The Posts controller
app/views/posts/index.html.erb
A view to display an index of all posts
app/views/posts/edit.html.erb
A view to edit an existing post
app/views/posts/show.html.erb
A view to display a single post …

32. What’s Next?
The Ruby on Rails guides The Ruby on Rails Tutorial The Ruby on Rails mailing list The #rubyonrails channel on irc.freenode.net

33. Rails Summary – from Saasbook
Rails defines three environments—development, production and test—each with its own copy of the database.
A migration is a script describing a specific set of changes to the database. As apps evolve and add features, migrations are added
Changing a database using a migration takes three steps: create the migration, apply the migration to development database, and after testing apply the migration to production database.
The rails generate migration generator fills in the boilerplate for a new migration, and the ActiveRecord::Migration class contains helpful methods for defining it.
rake db:migrate applies only those migrations not already applied to the development database. The method for applying migrations to a production database depends on the deployment environment.
Patterson, David; Fox, Armando ( ). Engineering Long-Lasting Software: An Agile Approach Using SaaS and Cloud Computing, Beta Edition

34. Active Record Summary
Active Record uses convention over configuration to infer database table names from the names of model classes, and to infer the names and types of the columns (attributes) associated with a given kind of model.
Basic Active Record support focuses on the CRUD actions: create, read, update, delete.
Model instances can be Created either by calling new followed by save or by calling create, which combines the two.
Every model instance saved in the database receives an ID number unique within its table called the primary key, …
Patterson, David; Fox, Armando ( ). Engineering Long-Lasting Software: An Agile Approach Using SaaS and Cloud Computing, Beta Edition

35. Summary: Haml
Haml allows you to intersperse HTML tags with Ruby code for your views. The result of evaluating Ruby code can either be discarded or interpolated into the HTML page.
For conciseness, Haml relies on indentation to reveal HTML element nesting.
Convention over configuration is used to determine the file names for controllers and views corresponding to a given model. If the RESTful route helpers are used, as in resources :movies, convention over configuration also maps RESTful action names to controller action (method) names.

36. HAML summary continued
Rails provides various helper methods that take advantage of the RESTful route URIs, including link_to for generating HTML links whose URIs refer to RESTful
Patterson, David; Fox, Armando ( ). Engineering Long-Lasting Software: An Agile Approach Using SaaS and Cloud Computing, Beta

37. Heroku - Cloud
Heroku is a cloud platform as a service (PaaS) supporting several programming languages. Heroku, one of the first cloud platforms, has been in development since June 2007 when it supported Ruby

38. https://toolbelt.heroku.com/
Heroku Toolbelt
What is it?
Heroku client - CLI tool for creating and managing Heroku apps
Foreman - an easy option for running your apps locally
Git - revision control and pushing to Heroku
Runs on your machine
$ heroku login
Enter your Heroku credentials.
Password:
Could not find an existing public key. Would you like to generate one? [Yn] Generating new SSH public key.
Uploading ssh public key /Users/adam/.ssh/id_rsa.pub

39. Heroku Toolbelt continued
You're now ready to create your first Heroku app:
$ cd ~/myapp
$ heroku create
Creating stark-fog done, stack is cedar |
Git remote heroku added
Technical details
The install script will add our repository and key to your apt sources and then have apt install the heroku and foreman packages from it. The heroku command line client will be installed into /usr/local/heroku and /usr/local/heroku/bin will be added to your PATH.

40. Heroku API

41. References – Cucumber and Rspec
Code
Download hwcuc-code.tgz
Copyrights apply to this source code. You may use the source code in your own projects, however the source code may not be used to create training material, courses, books, articles, and the like. We make no guarantees that this source code is fit for any purpose.

42. Behavior Driven Design in Cucumber
Describe behaviour in plain text
Write a step definition in Ruby
Run and watch it fail
Write code to make the step pass
Run again and see the step pass
Repeat 2-5 until green like a cuke
Repeat 1-6 until the money runs out

43. Cucumber Ex.: 1 Describe Behavior
Create feature and Scenarios

44. Cucumber Ex: 2 Write step definition

45. Cucumber Ex.: 3 Run/watch it fail
Given When Then

46. Rails Tutorial for Devise with RSpec and Cucumber
by Daniel Kehoe Last updated 1 September 2012 Ruby on Rails tutorial showing how to create a Rails 3.2 application using Devise with RSpec and Cucumber. Devise gives you ready-made authentication and user management. RSpec is a popular alternative to the Test::Unit testing framework. Cucumber is used for Behaviour Driven Development. Here’s what you can do: learn as-you-go by following the steps in this tutorial to build a starter app clone the example code from the GitHub repo for a ready-to-use starter app generate a customized starter app with the Rails Composer tool

47. Cucumber Ex.: 4 Write code to pass

48. Cucumber Ex.: 5 Run again

49. Cucumber Ex.: 6 Repeat 2-5 green

50. HW 3 : Behavior-Driven Design
Setup
git clone
git commit
git tag hw3-part1b
git diff hw3-part1b
git push origin --tags
Create a declarative scenario step for adding movies
Happy paths for filtering movies
Happy paths for sorting movies by title and by release date
HW 3 Submission - features directory only
tar czf features.tar.gz features/