Are you sure you want to be here? Me: IBM Software Developer. Rails: The hottest technology.

Transcription

1 Ruby On Rails

2 Are you sure you want to be here? Me: IBM Software Developer. Rails: The hottest technology.

3 You Are you an IBMer? Are you a programmer? MVC? DRY? Agile? Perl experience? J2EE/.NET/PHP experience? Database application development?

4 Aga Hype Details Ruby Break Rails

5 Administration Please sign the attance sheet

6 Why Browser-based applications Internal productivity applications Websites Build nifty Rails app Get on digg Earn twenty-two gajillion dollars Ruby on Rails: Build web applications Faster Easier Cheaper Better

7 What Ruby is a programming language If Perl and Smalltalk had a good-looking child And that child grew up with Lisp around a lot Rails is a framework written in Ruby

8 DB2 on Rails DB2-Express C Official IBM Rails Adapter Great support High-performance

9 Development Environment Aptana IDE DB2 Control Center Console IRB

10 Action Item Open IRB now. Start Menu, Run, cmd, irb

11 Ruby printf( Hello, CASCON\n ) #No semicolon, by the way

12 Hello, CASCON print( Hello, CASCON\n )

13 Hello, CASCON puts( Hello, CASCON )

14 Hello, CASCON puts Hello, CASCON

15 puts

16 Variables greeting = Hello, CASCON #No type, by the way puts greeting

17 Variables attees = 40

18 Objects greeting.upcase() greeting.upcase #Parentheses optional attees.gcd(7) #Surprised? 7.gcd(attees) #How about now?

19 Dynamic Types number = 7 string = Guess the number confusion = string string = number number = confusion puts string puts number

20 Methods def example puts IBM is great. example example() def example #Redefine at will message = IBM is great. puts message return message def example IBM is great #return statement optional

21 Parameters def print_and_return(variable) puts variable variable print_and_return( IBM is great )

22 Classes class Joke def tell print_and_return Someone set us up the bomb. cascon_joke = Joke.new cascon_joke.tell def tell(joke) joke.tell tell cascon_joke

23 Classes class String #Oh yes. def laugh print_and_return ha #{self} ha someone set us up.laugh cascon_joke.tell.laugh cascon_joke.tell.laugh.laugh cascon_joke.tell.laugh.laugh.upcase

24 Arrays array = [1,2,3, cascon_joke, IBM ] empty = [] another_empty = Array.new another = [empty, array]

25 Hashes my_hash = { DB2 => Cool., DB2 on Rails => Super Cool. } empty_hash = {} another_empty_hash = Hash.new puts my_hash[ DB2 ]

26 Proc say_hello = proc { puts hello } say_hello.call

27 Proc say = proc { something puts something } say.call( hello )

28 Alternate Syntax say = proc do something puts something

29 More Proc frily = proc { puts Hi! } unfrily = proc { puts You again. } def actor(mood) mood.call actor(frily) actor(unfrily)

30 Blocks def actor yield actor(&frily) actor { puts Hi! } actor do puts Hi!

31 Blocks and Procs def go_getter(&task) task.call go_getter do puts I can do anything!

32 The Point puts array array.each do item puts item puts my_hash my_hash.each do key, value puts #{key} is #{value}

33 Control if == 4 puts Thank goodness. else puts All your bugs are belong to us. puts Excellent. if == 100_000

34 Iteration 10.times do puts Hayo! (1..43).each do loop_counter puts loop_counter

35 Running Ruby Programs 1. Store your program in a.rb file 2. Run ruby your_program.rb 3.??? 4. Profit!!!

36 Gems Rubygems is a packaging system for Ruby programs. gem_server

37 require Open Aptana New Project Require answer.rb:

38 require curious.rb

39 require require net/http Net::HTTP.start( localhost, 8808 ) do http print( http.get( / ).body )

40 EchoBot Open echo_bot.rb. Don t run it! Start ejabberd Start Pandion. Log in with password Use a cmd window to go to C:\Documents and Settings\Administrator\My Documents\Aptana IDE Beta\JabberBots

41 RetrieverBot The final project: Jabber to Web bridge

42 Important Stuff for Another Day Modules Inheritance Metaprogramming Regular expressions More control structures

43 Rails In a command window, rails <projectname> In Aptana, open the Rails perspective New Rails Project File layout shows the Rails MVC and Convention over Configuration

44 Rails Hello World 1 Make a controller script/generate controller say Make a view called index.rhtml Put Hello world in the view.

45 Rails Hello World 2 Put a method called index in the controller Assign to instance variable Use it in the view with %>

46 More Basic Rails Connect to a database database.yml

47 database.yml

48 Model script/generate model entry word:string translation:string db/migrate, db:migrate

49 Rapid Application Development script/generate scaffold entry translate

50 Playtime Add some good data Add an empty entry(!)

51 What Scaffold Did Tour through the generated files

52 Test-driven Development Hack: rake db:migrate RAILS_ENV=test ruby test/unit/entry_test.rb

53 Test-driven Development

54 Fix the model validates_presence_of :word, :translation Run the test again Try the web browser!

55 A brief word on testing Part of the Rails way (Agile) Extensive functionality built-in Mocking frameworks Fixtures Other test types

56 Testing In unit tests: More validation methods Custom validation methods Functional tests get store/index assert_response :success assert_template index #example from Agile Web Development with Rails, 2 nd Ed.

57 Testing Integration tests #example from Agile Web Development with Rails, 2 nd Ed. def test_buying_a_product dave = regular_user dave.get /store/index dave.is_viewing index dave.checks_out DAVES_DETAILS dave.is_viewing index check_for_order

58 Alternative Testing Methods Leverage Ruby s flexibility This is a test: describe Account, " when first created" do it "should have a balance of $0" eql(money.new(0, :dollars))

59 Behaviour-Driven Development Use a Domain-Specific Language to express your specification as code The spec is your testing framework RSpec

60 AJAX Include Rails s default Javascript libraries In app/views/layouts/translate.rhtml <%= javascript_include_tag :defaults %> View the source

61 AJAX Let s AJAX-ify deletion. Ditch the destroy link Step 1: Replace with a button Step 2: Replace with an AJAX form Step 3: Give each row a DOM ID

62 AJAX Fix the controller: No more redirect Set a variable to mark which element was destroyed

63 AJAX Create AJAX view destroy.rjs :fade

64 AJAX Seamless integration for responsiveness Entire Scriptaculous library of visual effects Full Prototype support Easy to use YUI, Dojo, or your own JS

65 Relationships A hotel has many rooms A room belongs to a hotel

66 Hotels and Rooms script/generate model hotel name:string script/generate model room number:integer hotel_id:integer db:migrate

67 Hotels and Rooms

68 script/console IRB for rails applications Open it now through a command window

69 Some script/console commands here = Hotel.new(:name => Sheraton Markham ) here.save h = Hotel.create(:name => California ) Hotel.find(:all) h.rooms r = Room.create(:hotel => h, :number => 100) h.rooms h.reload h.rooms h.rooms.create(:number => 101) h.rooms Room.find(:all)

70 A Quick Integration Project A plain-text interface: Word in the request Translation in the response For simplicity, add a new translate action

71 New Action def lookup entry = Entry.find_by_word(params[:q]) if entry result = entry.translation else result = "Don't know '#{params[:q]}'" rer(:text => result, :layout => false)

72 Back to the RetrieverBot Hmmm

73 Next Step The best book.

74 After That Build nifty Rails app Get on digg Earn twenty-two gajillion dollars Give me eleventy gabillion of it

75 Appix: Google Retriever Bot require 'rubygems' require 'xmpp4r-simple' require 'net/http' class RetrieverBot def initialize(host, port, = @path = host, port, path def start loop do message handle message private Query = 'q=' def handle(message) result = nil do http result = http.get( build_url_for(message) result.body) def get_words(message) message.body.split def + "?" + Query + get_words(message).join('+') if FILE == $0 RetrieverBot.new(' '80', '/search').start

76 Appix: Advanced Retriever Bot require 'rubygems' require 'xmpp4r-simple' require 'net/http' class RetrieverBotAdvance < Jabber::Simple def initialize(host, port, @path = host, port, path def start loop do received_messages do message handle message private Query = 'q=' def handle(message) result = nil do http result = http.get( build_url_for(message) ) deliver(message.from, result.body) def get_words(message) message.body.split def + "?" + Query + get_words(message).join('+') if FILE == $0 RetrieverBotAdvance.new('localhost', '3000', '/translate/lookup').start

77 Disclaimer The IBM Center for Advanced Studies (CAS) regularly publishes technical documents that are aimed at facilitating an exchange of information. These reports are written by individuals or groups of authors and represent their opinions and do not necessarily reflect those of IBM. In the event of questions or concerns regarding individual reports or presentations, addresses have been provided for most authors. Alternatively, please feel free to contact CAS at CAS is dedicated to providing a forum for IBM employees, research affiliates, and university students to publish results of their work, their views on technical issues, book reviews, and workshop reports.

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