Developing Web Application using Ruby on Rails Ben

Developing Web Application using Ruby on Rails Ben Curren CTO and Founder

Agenda § What is Ruby on Rails? § Overview of Rails § Create a Todo List Web Application using Rails § Introduction to Ruby § More Information § Questions March 2006 Presentation

My Background § Started developing Java in 1996 § Developed many web based applications using Java / J 2 EE, PHP and ASP. net. § Have worked extensively with C++ / C developing Windows desktop applications. § Developed desktop application using Win. Forms and. Net 1. 1. § Have been working with Ruby on Rails for about months. § CTO and Founder of Esomnie. We develop web applications using Ruby on Rails, Java, and ASP. net. March 2006 Presentation

Assumptions about the audience § I have made a couple assumptions about the audience: § § § You have experience with an object-oriented programming language. You understand the basics of HTTP. You understand XHTML / HTML March 2006 Presentation

What is Ruby on Rails? § Rails is a web development framework § Ruby is a programming language § Rails is developed in Ruby. March 2006 Presentation

Overview of Rails

What is Rails? § Full stack web application framework § Open source and Free § Active and growing community March 2006 Presentation

What does Rails Provide? § MVC § Active. Record § Unit Testing Framework § Migrations § And Active. Resource, Action. Web. Service, Active. Support, Action. Mailer, Action. Pack March 2006 Presentation

Rails Opinions § Convention over configuration § Agile software development § Test driven development March 2006 Presentation

Create a Todo List Web Application using Rails

The application § A web application that allows a user to create a todo list § Users will be able to view a list of their todo lists. § Users will be able to create new todo lists. § They will be able to add items to the list. (not today, we will not have time) March 2006 Presentation

Create the project § Create a new rails project named todo. § Creates the rails directory structure and initial configuration. rails todo March 2006 Presentation

Directory Structure todo app controllers helpers models views layouts config db public script test functional unit integration vendor … March 2006 Presentation

Create the databases § Create a file called db/create. sql § Run the script with mysql -uroot -p < db/create. sql create database todo_development; create database todo_test; create database todo_production; grant all on todo_development. * to 'tododev'@'localhost' identified by 'tododev'; grant all on todo_test. * to 'todotest'@'localhost' identified by 'todotest'; grant all on todo_production. * to 'todo'@'localhost' identified by 'todo'; March 2006 Presentation

Update the Database Configuration § Supply the username and password in config/database. yml development: adapter: mysql database: todo_development username: tododev password: tododev host: localhost test: adapter: mysql database: todo_test username: todotest password: todotest host: localhost production: adapter: mysql database: todo_production username: todo password: todo Marchlocalhost 2006 Presentation host:

Generate the List model § Create the List model. § It will hold the name of the todo list. script/generate model list exists app/models/ exists test/unit/ exists test/fixtures/ create app/models/list. rb create test/unit/list_test. rb create test/fixtures/lists. yml create db/migrate/001_create_lists. rb March 2006 Presentation

Create the List Migration § A migration allows you to modify the database schema using Ruby. § Migrations provide versioning. § Update the file called db/migrate/001_create_lists. rb class Create. Lists < Active. Record: : Migration def self. up create_table : lists do |t| t. column "name", : string t. column "created_at", : string t. column "updated_at", : string end def self. down drop_table : lists end March 2006 Presentation

Run the Migrations rake migrate (in /Users/bcurren/projects/todo) == Create. Lists: migrating ================ -- create_table(: lists) -> 0. 4252 s == Create. Lists: migrated (0. 4269 s) ============ March 2006 Presentation

The List Model § Without writing any mapping code, you can start using the List model. § Here are the contents of app/model/list. rb class List < Active. Record: : Base end March 2006 Presentation

Create and Store a List Object script/console Loading development environment. >> list = List. new => #<List: 0 x 256680 c @attributes={"name"=>nil, "updated_at"=>nil, "created_at"=>nil}, @new_record=true> >> list. name = "Ben's Todo List" => "Ben's Todo List" >> list. save => true March 2006 Presentation

Require List. name § Make the name of the list required. § Update the contents of app/model/list. rb class List < Active. Record: : Base validates_presence_of : name end March 2006 Presentation

Test that List. name is required § Add a test to make sure name is required. (test/unit/list_test. rb) class List. Test < Test: : Unit: : Test. Case fixtures : lists def test_name_required List. new do |list| list. name assert !list. valid? assert list. errors. on(: name) end end March 2006 Presentation

Run the Unit Tests rake test: unit (in /Users/bcurren/projects/todo) /usr/local/bin/ruby -Ilib: test "/usr/local/lib/ruby/gems/1. 8/gems/rake 0. 7. 1/lib/rake_test_loader. rb" "test/unit/list_test. rb" Loaded suite /usr/local/lib/ruby/gems/1. 8/gems/rake 0. 7. 1/lib/rake_test_loader Started Finished in 0. 103404 seconds. 1 tests, 2 assertions, 0 failures, 0 errors March 2006 Presentation

Rails MVC Overview March 2006 Presentation

Create the list of todo lists § Create a list controller with an action named list § The action list uses the model to get all the todo lists and places them in a variable called @lists § Create a view the loops over the @lists and renders the html view March 2006 Presentation

Create the List. Controller script/generate controller List list exists app/controllers/ exists app/helpers/ create app/views/list exists test/functional/ create app/controllers/list_controller. rb create test/functional/list_controller_test. rb create app/helpers/list_helper. rb create app/views/list. rhtml March 2006 Presentation

The List. Controller § The generated file app/controllers/list_controller. rb class List. Controller < Application. Controller def list end March 2006 Presentation

The list action § Need to create an array of List objects in the database. § app/controllers/list_controller. rb class List. Controller < Application. Controller def list @lists = List. find : all end March 2006 Presentation

The List. Controller. Test § The generated list controller test in test/functionals/list_controller_test. rb class List. Controller. Test < Test: : Unit: : Test. Case def setup @controller = List. Controller. new @request = Action. Controller: : Test. Request. new @response = Action. Controller: : Test. Response. new end March 2006 Presentation

The test for the list action § I added the test for the list action in The generated list controller test in test/functionals/list_controller_test. rb. def test_list get : list assert_response : success assert_template 'list' assert_not_nil assigns(: lists) end March 2006 Presentation

Run the functional tests rake test: functionals (in /Users/bcurren/projects/todo) /usr/local/bin/ruby Ilib: test"/usr/local/lib/ruby/gems/1. 8/gems/rake 0. 7. 1/lib/rake_test_loader. rb" "test/functional/list_controller_test. rb" Loaded suite /usr/local/lib/ruby/gems/1. 8/gems/rake 0. 7. 1/lib/rake_test_loader Started Finished in 0. 095025 seconds. 1 tests, 3 assertions, 0 failures, 0 errors March 2006 Presentation

The list view § Update the template app/views/list. rhtml to display a list of the todo lists. <h 1>Todo Lists</h 1> <ul id="todo_list"> <%= render : partial => 'list', : collection => @lists %> </ul> March 2006 Presentation

The list partial § Create a file name app/views/list/_list. rhtml to display each list item. <li><%= list. name %></li> March 2006 Presentation

Check your work § Start up the web server. WEBrick comes with Rails and is great for testing. script/server & [1] 6686 harley: ~/projects/todo bcurren$ => Booting WEBrick. . . => Rails application started on http: //0. 0: 3000 => Ctrl-C to shutdown server; call with --help for options [2006 -10 -08 09: 50: 46] INFO WEBrick 1. 3. 1 [2006 -10 -08 09: 50: 46] INFO [powerpc-darwin 8. 6. 0] ruby 1. 8. 4 (2005 -12 -24) [2006 -10 -08 09: 50: 46] INFO pid=6686 port=3000 WEBrick: : HTTPServer#start: March 2006 Presentation

View the list in the browser § Open your browser and type in the URL http: //localhost: 3000/list March 2006 Presentation

Add a default layout to your pages § Create a layout named app/views/layouts/default. rhtml <!DOCTYPE html PUBLIC "-//W 3 C//DTD XHTML 1. 0 Strict//EN" "http: //www. w 3. org/TR/xhtml 1/DTD/xhtml 1 -strict. dtd"> <html xmlns="http: //www. w 3. org/1999/xhtml" xml: lang="en"> <head> <%= javascript_include_tag : defaults %> </head> <body> <%= @content_for_layout %> </body> </html> March 2006 Presentation

Add the layout to the Application. Controller § Open the file app/controllers/application_controller. rb § All of the controllers in the app will now use the layout default. You can override this in each controller. class Application. Controller < Action. Controller: : Base layout 'default' end March 2006 Presentation

Create a new todo list using AJAX § First, let’s create the form on the app/views/list. rtml page. <div> <%= form_remote_tag( : url => {: controller => 'list', : action => 'add'}, : html => {: id => 'add_item_form', }) %> <label for="list_name">Name: </label> <%= text_field 'list', 'name', : size => 20 %> <%= submit_tag 'Create' %> <%= end_form_tag %> </div> March 2006 Presentation

Create the add action § Add the following action to app/controllers/list_controller. rb def add @list = List. new(params[: list]) @list. save! end March 2006 Presentation

Create the add rjs file § Create a file named app/views/list/add. rjs page. insert_html : bottom, "todo_list", : partial => 'list' page. visual_effect : highlight, "todo_list" page. form. reset 'add_item_form' March 2006 Presentation

Test the AJAX add § The functional test requires a plugin and I don’t have time to include it here. See http: //glu. ttono. us/articles/2006/05/29/guide-test-drivenrjs-with-arts for a good example. § http: //localhost: 3000/list March 2006 Presentation

The application stats rake stats (in /Users/bcurren/projects/todo ) +-----------+-------+---------+-------+ | Name | Lines | LOC | Classes | Methods | M/C | LOC/M | +-----------+-------+---------+-------+ | Helpers | 5 | 4 | 0 | 0 | | Controllers | 16 | 12 | 2 | 1 | 4 | | Components | 0 | 0 | 0 | | | 20 | 16 | 2 | 3 | 1 | 3 | | Models | 3 | 1 | 0 | 0 | | | 13 | 11 | 1 | 9 | | Libraries | 0 | 0 | 0 | | | 0 | 0 | 0 | Functional tests Unit tests Integration tests +-----------+-------+---------+-------+ | Total | 57 | 46 | 6 | 1 | 5 | +-----------+-------+---------+-------+ Code LOC: 19 March 2006 Test LOC: 27 Presentation Code to Test Ratio: 1: 1. 4

Introduction to Ruby

What is Ruby § Object-oriented, dynamic scripting language § Developed by Yukihiro Matsumoto in 1995 § Flexible and simple syntax § Based on Perl, Smalltalk, Eiffel, Ada and Lisp March 2006 Presentation

Ruby is Object-Oriented § default_expiration_date is a public static method of Credit. Card § day is a method of Fix. Num § day returns the number of seconds in x days § from_now is a method of Fix. Num § from_now returns the x seconds from now class Credit. Card def self. default_expiration_date 1. day. from_now end March 2006 Presentation

Ruby is Dynamic § Ruby has open classes. § You can open up a class and add or override methods. § The methods day and from_now are not part of the Ruby Fix. Num class. Rails adds them with the Action. Pack module. class Fix. Num def days self * 24. hours end alias : days end March 2006 Presentation

Ruby is Really Dynamic § Add methods, instance, methods and more at runtime. § This can create an accessor and instance variable like this. class Credit. Card attr_writer : number end March 2006 Presentation

Adding methods and variables at runtime § attr_writer could be implemented like this. class Object def self. attr_writer(method) eval %Q{ def #{method. to_s}=(value) @#{method. to_s} = value end } end March 2006 Presentation

The Magic of method_missing § How would you write a method that prints out its name if the method name starts with print_? § For example: Example. print_my_name prints “print_my_name” class Example def self. method_missing(method_name, *args) puts method_name if method_name =~ /^print_/ end March 2006 Presentation

Ruby’s Closures (Blocks) § A closure allows a programmer to provide a block of code for a method to run. § This example prints out each search engine. (taken from www. rubylang. org) search_engines = %w[Google Yahoo MSN]. map do |engine| “http: //www. ” + engine. downcase + “. com” end March 2006 Presentation

Implementation of Array. map § Here is an implementation of Array. map class Array def map(array) new_array = Array. new array. each {|element| new_array << yield element } new_array end March 2006 Presentation

Ruby has Much More … § Mixins - a collection of methods you can include into any class § Exception handling § Garbage collection § Single inheritance § Duck typing (no interfaces) March 2006 Presentation

More Information

Deploying Rails Applications § Rails apps are compatible with Unix and Windows environments § Rails apps can be deployed on multiple web server configurations § § § Mongrel - Ruby web server, high performace and is currently the recommended server WEBrick – a standalone Ruby web server, easy for development Fast. CGI – running behind Apache or Light. TPD. Many problems with this. § Easy control of the deployment with Capistrano § A scripting tool to control the deployment of the application on multiple sites § Easy control of schema migration § rake migrate VERSION=3 March 2006 Presentation

More Information § Books Agile Web Development With Rails (get the second edition) § Rails Recipes § The Ruby Pick Axe Book § § Active and growing community § § wiki. rubyonrails. com api. rubyonrails. com March 2006 Presentation

Feedback § Please provide feedback. § § § Was this too detailed? Should I give more of an overview? Did I move to quickly / slow? Do you like a presentation with this much code? Did you like that I deveoped an example? § Here is how: § § Log into your account Go to the “Session Details” page Click on the link name "Session Evaluation” on my presentation page Submit your feedback March 2006 Presentation

Questions? My Contact Information Ben Curren ben@esomnie. com Web site: www. esomnie. com Blog: www. jotthought. com Interested in a contract or full-time job? Email jobs@esomnie. com. March 2006 Presentation