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1 24 Ruby on Rails 2008 Pearson Education, Inc. All rights reserved. 2 Convention is the ruler of all. — Pindar Where the telescope ends, the microscope begins. Which of the two has the grander view? — Victor Hugo …We grow more partial for the observer’s sake. — Alexander Pope 2008 Pearson Education, Inc. All rights reserved. 3 Those who cannot remember the past are condemned to repeat it. — George Santayana Let’s look at the record. — Alfred Emanuel Smith All that matters is that the miraculous become the norm. — Henry Miller 2008 Pearson Education, Inc. All rights reserved. 4 OBJECTIVES In this chapter you will learn: Basic Ruby programming. How to use the Rails framework. The Model-View-Controller paradigm. How to use ActiveRecord to model a database. How to construct web applications that interact with a database. How to create a web-based message forum. How to develop Ajax-enabled applications in Ruby on Rails. How to use the built-in Script.aculo.us library to add visual effects to your programs. 2008 Pearson Education, Inc. All rights reserved. 5 24.1 Introduction 24.2 Ruby 24.3 Rails Framework 24.4 ActionController 24.5 A Database-Driven Web Application 24.6 Case Study: Message Forum and ActionView 24.6.1 Logging In and Logging Out 24.6.2 Embellishing the Models 24.6.3 Generating Scaffold Code 24.6.4 Forum Controller and Forum Views 24.6.5 Message Controller and Message Views 24.6.6 Ajax-Enabled Rails Applications 24.7 Script.aculo.us 24.8 Wrap-Up 24.9 Web Resources 2008 Pearson Education, Inc. All rights reserved. 6 24.1 Introduction • Ruby on Rails (also known as RoR or just Rails) is a framework for developing data-driven web applications. • A web framework is a set of libraries and useful tool that can be used to build dynamic web applications. • Ruby on Rails is different from most other programming languages because it takes advantage of many conventions to reduce development time. If you follow these conventions, the Rails framework generates substantial functionality and perform many tasks for you. • Ruby on Rails has built-in libraries for performing common web development tasks, such as interacting with a database, sending mass e-mails to clients or generating web services. • Rails has built-in libraries that provide Ajax functionality, improving the user experience. Rails is quickly becoming a popular environment for web development. • Ruby on Rails was created by David Heinemeier Hansson of the company 37Signals. 2008 Pearson Education, Inc. All rights reserved. 7 24.2 Ruby • The Ruby scripting language was developed by Yukihiro “Matz” Matsumoto in 1995 to be a flexible, object-oriented scripting language. • Ruby’s syntax and conventions are intuitive—they attempt to mimic the way a developer thinks. Ruby is an interpreted language. • Instant Rails is a stand-alone Rails development and testing environment that includes Ruby, Rails, MySQL, Apache, PHP and other components necessary to create and run Rails applications. • If you are using Mac OS X, there is an application similar to Instant Rails called Locomotive. • The method puts prints the text to the terminal, followed by a newline. • A method can have parentheses surrounding its parameters, but this is not typical in Ruby unless they are used to avoid ambiguity. • A line of Ruby code does not have to end with a semicolon, although one can be placed there. • One way to run a Ruby script is to use the Ruby interpreter. • IRB (Interactive Ruby) can be used to interpret Ruby code statement by statement. 2008 Pearson Education, Inc. All rights reserved. 8 Fig. 24.1 | Instant Rails application running. 2008 Pearson Education, Inc. All rights reserved. 9 24.2 Ruby (Cont.) • Ruby uses dynamic typing, which allows changes to a variable’s type at execution time. • Everything is an object in Ruby, so you can call methods on any piece of data. • Hash Objects are mapped to other Objects in key/value pairs. • The exclamation point after a method name is a Ruby convention indicating that the object on which the method is called will be modified. • Ruby has support for code blocks—groupings of Ruby statements that can be passed to a method as an argument. • The initialize method acts like a constructor in other object-oriented languages—it is used to declare and initialize an object’s data. • When each instance of a class maintains its own copy of a variable, the variable is known as an instance variable and is declared in Ruby using the @ symbol. • Classes can also have class variables, declared using the @@ symbol, that are shared by all copies of a class. • When an object is concatenated with a string, the object’s to_s method is called to convert the object to its string representation. 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.2: welcome.rb 2 # Simple Ruby program. 3 puts "Welcome to Ruby!" Welcome to Ruby! 10 Outline The puts command writes a line of text to the console welcome.rb 2008 Pearson Education, Inc. All rights reserved. 11 Fig. 24.3 | Launching the Ruby Interpreter in Instant Rails. 2008 Pearson Education, Inc. All rights reserved. 12 Fig. 24.4 | Using the Ruby interpreter to run a simple Ruby script. 2008 Pearson Education, Inc. All rights reserved. 13 Fig. 24.5 | Using Interactive Ruby to execute Ruby statements. 2008 Pearson Education, Inc. All rights reserved. 1 2 # Fig. 24.6: types.rb # Method calls on numeric and string data 3 4 5 myvar = 5.7 # binds the value 5.7 to myvar puts "The value of myvar is #{myvar}" 6 7 8 9 myvar = myvar.round # return a rounded value Fixnum puts "The rounded value of myvar is #{myvar}" myvar = 5.4 # bind the value 5.4 to myvar 10 puts "The value of myvar is #{myvar}" 11 12 myvar = myvar.round # return a rounded value Fixnum Ruby uses = as the Outline assignment operator Enclosing a variable in curly braces ({})preceded types.rb by a pound sign (#) causes it to be interpolated (1 of 2) 14 You can call the round method on any variable of type Fixnum 13 puts "The rounded value of myvar is #{myvar}" 14 15 myvar = "mystring" # bind the value 'mystring' to myvar 16 puts "The value of myvar is '#{myvar}'" Ruby variables are dynamically typed, so variables have no explicit type, but can hold any type of data at any time 2008 Pearson Education, Inc. All rights reserved. 17 15 18 myvar = myvar.capitalize # capitalize the value of myvar 19 puts "The capitalized form of myvar is '#{myvar}'" The 20 21 myvar = "my string" # bind the value 'my string' to capitalize method capitalizes the myvar first letter of a string 22 puts "The value of myvar is '#{myvar}'" 23 24 myvar = myvar.capitalize # capitalize the value of myvar 25 puts "The capitalized form of myvar is '#{myvar}'" The The The The The The The The Outline types.rb (2 of 2) value of myvar is 5.7 rounded value of myvar is 6 value of myvar is 5.4 rounded value of myvar is 5 value of myvar is 'mystring' capitalized form of myvar is 'Mystring' value of myvar is 'my string' capitalized form of myvar is 'My string' 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.7: arraysAndHashes.rb 2 # Arrays and hashes in Ruby. 3 fruits = [ "mango", "orange", 4 puts "The length of the fruits array is #{fruits.length}" # output 5 puts "The first fruit is #{fruits[0]}" # output first element 6 puts "The last fruit is #{fruits[-1]}\n\n" # output last element 16 "apple", "pear" ] # create an array Arrays can be created lengthusing comma-separated lists in square brackets 7 8 fruits.reverse! # reverse the order of the elements in the fruits array 9 puts "The length of the fruits array is #{fruits.length}" # output length 10 puts "The first fruit is #{fruits[0]}" # output first element 11 puts "The last fruit is #{fruits[-1]}\n\n" # output last element 12 13 # a simple hash 14 food = { "mango" => "fruit", "banana" => "fruit", "onion" => "vegetable" 15 puts "The length of the food hash is #{food.length}" # output length 16 puts "A mango is a #{food["mango"]}" # output value of key mango 17 puts "An onion is a #{food["onion"]}" # output value of key onion The length of the fruits array is 4 The first fruit is mango the last fruit is pear The length of the fruits array is 4 The first fruit is pear the last fruit is mango The length of the food hash is 3 A mango is a fruit An onion is a vegetable Outline arraysAndHashes .rb The length of an array is stored in its length Elements are accessed property using square bracket notation; You can also access items starting } from the end of the array using negative indices You can create a hash, which stores key-value pairs, by separating keys from values with the => operator and enclosing the list in curly braces 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.8: controlStatements.rb 2 # Conditionals, loops, and codeblocks. 3 def letter_grade( x ) # define method letterGrade 4 5 if x >= 90 # if x is greater than or equal to 90 "A" # grade is A 6 elsif x >= 80 # if x is greater than or equal to 80 7 8 9 10 11 12 "B" # grade is B elsif x >= 70 # if x is greater than or equal to 70 "C" # grade is C elsif x >= 60 # if x is greater than or equal to 60 "D" # grade is D else # grade is less than 60 13 "F" # grade is F 14 end # if 15 end # method letterGrade 16 17 Outline Control Statements.rb Methods are defined using the def keyword, and method definitions end with the end keyword 17 students = { "John" => 100, "Sue" => 92, "Tom" => 56, "Jill" => 80 } 18 19 students.each() { |key, value| # display the letter grade for each student 20 puts "#{key} received a #{letter_grade(value)}" 21 } # end codeblock Jill received a B Sue received a A John received a A Tom received a F The each method can be used on arrays to iterate through their elements. The parameters of a code block are placed between pipe characters (||)at the beginning of the block 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.9: Classes.rb 2 3 # A Ruby class. class Point 4 @@num_points = 0 # initialize numPoints 5 6 7 8 # create a new Point object def initialize(x, y) @x = x # initialize x-coordinate 9 @y = y # initialize y-coordinate 18 Classes are defined beginning with the class keyword and ending with the end keyword Outline Classes.rb Class variables are preceded (1 of 2) by @@ Create a constructor by 10 11 12 @@num_points +=1 # increment numPoints counter end # method initialize 13 14 15 # return a string containing the x-y values def to_s Every return "x: #{@x}; y: #{@y}" 16 end # method to_s defining an initialize Instance variables are method preceded by @ class has a to_s method that returns a string representation of the object. This class overrides its to_s method 2008 Pearson Education, Inc. All rights reserved. 17 19 18 # return how many Points have been instantiated 19 def num_points 20 21 return @@num_points end # method numPoints 22 end # class Point 23 24 p = Point.new( 8, 9 ) # instantiate a Point 25 q = Point.new( 1, 1 ) # instantiate another Point 26 puts "the value of p is '#{p}'" 27 puts "the value of q is '#{q}'" 28 puts "the number of points created is #{p.num_points}" the value of p is 'x: 8; y: 9' the value of q is 'x: 1; y: 1' the number of points created is 2 Outline Classes.rb (2 of 2) Create an instance using the class name and new, supplying any arguments required by the constructor 2008 Pearson Education, Inc. All rights reserved. 20 24.3 Rails Framework • While users have benefitted from the rise of database-driven web applications, web developers have had to implement rich functionality with technology that was not designed for this purpose. • The Rails framework combines the simplicity of development that has become associated with Ruby with the ability to rapidly develop database-driven web applications. • Ruby on Rails is built on the philosophy of convention over configuration—if you follow certain programming idioms, your applications will require little or no configuration and Rails will generate substantial portions of the applications for you. • The Model-View-Controller (MVC) architectural pattern separates application data (contained in the model) from graphical presentation components (the view) and input-processing logic (the controller). • ActiveRecord is used to map a database table to an object. • ActionView is a set of helper methods to modify user interfaces. • ActionController is a set of helper methods to create controllers. 2008 Pearson Education, Inc. All rights reserved. 21 Fig. 24.10 | Model-View-Controller architecture. 2008 Pearson Education, Inc. All rights reserved. 22 Fig. 24.11 | Rails directory structure for a new Rails application. 2008 Pearson Education, Inc. All rights reserved. 23 24.4 ActionController and ActionView • Ruby on Rails has two classes, ActionController and ActionView, that work together to process a client request and render a view. • To generate a controller in Rails, you can use the built-in Controller generator by typing ruby script/generate controller name. • A Ruby on Rails application must be run from a web server • Instant Rails comes with a built-in web server named Mongrel, which is easy to use to test Rails applications on the local machine. • When generating output, a controller usually renders a template—an XHTML document with embedded Ruby that has the .rhtml filename extension. • The request object contains the environment variables and other information for a web page. • Erb (embedded Ruby) that is located between the <%= %> tags in rhtml files is parsed as Ruby code and formatted as text. • A set of Ruby tags without an equals sign—<% %>—represents statements to execute as Ruby code but not formatted as text. • Rails allows you to add headers and footers with a layout—a master view that is displayed by every method in a controller. • A layout can generate a template for a specific method using yield. 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.12: app/controllers/welcome_controller.rb 2 # Simple controller that renders a message on a web page. 3 class WelcomeController < ApplicationController 4 # render text in page 5 def index 6 7 8 render :text => "Welcome to Ruby on Rails!" end # method index end # class WelcomeController 24 Outline app/controllers/ Call the render method, welcome_ specifying its parameter controller.rb using the text symbol 2008 Pearson Education, Inc. All rights reserved. 25 Fig. 24.13 | Starting the Mongrel web server. 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.14: app/controllers/welcome_controller.rb 2 # Simple controller that passes a parameter to the view. 3 class WelcomeController < ApplicationController 4 # set server_name to server information 5 def hello 6 7 8 @server_name = request.server_software # retrieve software of server end # method hello end # class WelcomeController 26 Outline app/controllers/ welcome_ controller.rb Define a class variable in the controller that contains information about the server 2008 Pearson Education, Inc. All rights reserved. 1 <?xml version = "1.0" encoding = "utf-8"?> 2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 3 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 27 Outline 4 5 <!-- Fig. 24.15: app/views/welcome/hello.rhtml --> 6 <!-- View that displays the server name. --> 7 <html xmlns = "http://www.w3.org/1999/xhtml"> 8 <head> 9 app/views/welcome /hello.rhtml <title>hello</title> 10 </head> 11 <body style = "background-color: lightyellow"> 12 <strong>Hello from the view!</strong><br /> 13 The server you are coming from is 14 <em><%= @server_name %></em> 15 </body> 16 </html> The view has access to the controller’s class variables 2008 Pearson Education, Inc. All rights reserved. 1 <?xml version = "1.0" encoding = "utf-8"?> 2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 3 28 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> Outline 4 5 <!-- Fig. 24.16: app/views/layouts/welcome.rhtml --> 6 <!-- Layout that displays a greeting. --> 7 <html xmlns = "http://www.w3.org/1999/xhtml"> 8 <head> 9 app/views/layouts /welcome.rhtml <title><%= controller.action_name %></title> 10 </head> 11 <body style = "background-color: lightyellow"> 12 Hello from the Layout!<br /> 13 <hr /> 14 <%= yield %> <!-- render template --> 15 </body> 16 </html> A controller’s action_name method displays the action that is currently being called The layout yields to the view associated with the current action 2008 Pearson Education, Inc. All rights reserved. 29 Fig. 24.17 | Creating a model in the Ruby Console. 2008 Pearson Education, Inc. All rights reserved. 30 24.5 A Database-Driven Web Application • Rails makes extensive use of Object-Relational Mapping (ORM) that maps a database to application objects. • The objects that Rails uses to encapsulate a database inherit from ActiveRecord. • One ActiveRecord convention is that every model that extends ActiveRecord::Base in an application represents a table in a database. • By convention, the table that the model represents has a name which is the lowercase, pluralized form of the model’s name. • Rails uses a generator to create the Employee model. You use a generator by typing ruby script/generate model employee in the Ruby Console, after navigating to your application directory. 2008 Pearson Education, Inc. All rights reserved. 31 24.5 A Database-Driven Web Application (Cont.) • The ActiveRecord object has a special feature called Migration, which allows you to perform database operations within Rails. • ActiveRecord has built-in functionality for many create, retrieve, update and destroy methods known in Rails as CRUD. • We can execute the migration using Ruby’s rake command by typing rake db:migrate, which will call the self.up method of all the migrations located in your db/migrate directory. • If you ever want to roll back the migrations, you can type rake db:migrate VERSION=0, which calls each migration’s self.down method. • The scaffold method is a powerful tool that automatically creates CRUD functionality. It creates methods such as new, edit and list so you don’t have to create them yourself. 2008 Pearson Education, Inc. All rights reserved. 1 2 # Fig. 24.18: db/migrate/001_create_employees.rb # Database migration script modified to add data to the table 3 4 class CreateEmployees < ActiveRecord::Migration # create the table with three columns and insert some rows. 5 6 7 8 9 10 11 12 13 14 15 16 def self.up create_table :employees do |t| t.column :first_name, :string t.column :last_name, :string t.column :job_title, :string Outline The up method in a migration does the work on the database db/migrate/001_ create_employees We create a table .rb in the database with three columns containing strings end # do block Employee.create :first_name => "Sue", :last_name => "Green", :job_title => "Programmer" Employee.create :first_name => "Meg", :last_name => "Gold", :job_title => "Programmer" Employee.create :first_name => "John", :last_name => "Gray", 17 18 :job_title => "Programmer" end # method self.up 19 20 21 # reverse the migration, delete the table that was created def self.down 22 32 drop_table :employees 23 end # method self.down 24 end # class CreateEmployees Create three entries in the table, specifying values for each field The down method undoes what the up method did so that you can roll changes forward and we back To undo the changes, simply drop the table 2008 Pearson Education, Inc. All rights reserved. 33 Common Programming Error 24.1 If the code that comes after the creation of the table in the self.up is erroneous, the migration will fail, and will not be able to execute again because the table will already exist. Also, Rails will not have marked the migration as successfully completed, so the version will still be 0 and the migration cannot be rolled back. One way to prevent this problem is to force the table to be dropped every time before creating it. Another solution is splitting up the migration into smaller discrete migrations, one to create the table and another to insert data in the table. 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.19: employee.rb 2 # Generated code for an Employee Model. 3 class Employee < ActiveRecord::Base 4 end # class Employee 34 Outline employee.rb 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.20: app/controllers/employees_controller.rb 2 # Provides all of the functionality for the application. 3 4 class EmployeesController < ApplicationController scaffold :employee # create scaffold code for controller 35 Outline The scaffold method dynamically generates any CRUD methods that are not already defined in the app/controllers/ controller employees_contro 5 6 # override scaffold list method 7 8 def list @employees = Employee.find( :all ) # return an array of Employees 9 end # method list 10 end # class EmployeeController ller.rb Our list method (called when the list action is invoked) creates an array of all employees so that the view can display them 2008 Pearson Education, Inc. All rights reserved. 36 Fig. 24.21 | View of the new action when generated by the scaffold. 2008 Pearson Education, Inc. All rights reserved. 1 <?xml version = "1.0" encoding = "utf-8"?> 2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 3 37 Outline "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 4 5 <!-- Fig. 24.22 app/views/employees/list.rhtml --> 6 <!-- A view that displays a list of Employees. --> 7 <html xmlns = "http://www.w3.org/1999/xhtml"> 8 <head> 9 app/views/ employees/list .rhtml <title>List of Employees</title> 10 </head> 11 <body style="background-color: lightyellow"> 12 <h1>List of Employees</h1> 13 <ol> 14 <% for employee in @employees %> 15 <!-- create a list item for every employee with his full name --> 16 Loop through each employee in the database <li><%= employee.first_name %> <%= employee.last_name %></li> 17 <% end %> 18 </ol> 19 </body> 20 </html> Access each employee’s first and last name as properties of the current employee object 2008 Pearson Education, Inc. All rights reserved. 38 24.6 Case Study: Message Form • Validators that will be called when the database is modified, can be applied to an object that inherits from ActiveRecord. • The method validates_presence_of ensures that all the fields specified by its parameters are not empty. • The method validates_format_of matches all the fields specified by its parameters with a regular expression. • The link_to method is used to link to an action in the controller and pass arguments to it. • A partial is a block of HTML and embedded Ruby code stored in another file and inserted directly into the document. • Rails includes a JavaScript library called Prototype that contains easy-to-use crossbrowser Ajax functions. • The javascript_include_tag helper method is used to link in JavaScript libraries. • The link_to_remote method allows us to link to JavaScript that we included in the layout file. • Specifying the url and update parameters inside the link_to_remote method tells Rails to convert these tags into prototype Ajax.Updater objects that will update the page asynchronously. 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.23: db/migrate/001_create_users.rb 2 # Database migration script modified to add data to the table. 3 class CreateUsers < ActiveRecord::Migration 4 # create and configure users table 5 def self.up 6 create_table :users do |t| 7 t.column :name, :string, :limit => 11 8 t.column :password, :string 9 39 Outline Create a database table to store users db/migrate/001_ create_users.rb end # do block 10 11 12 User.create :name => "user1", :password => "54321" Create a test user end # method self.up 13 14 # remove users table 15 def self.down 16 drop_table :users 17 end # method self.down 18 end # class CreateUsers 2008 Pearson Education, Inc. All rights reserved. 40 Common Programming Error 24.2 Creating a column without explicitly specifying a limit on length will cause Rails to truncate the data entered into the database with database-defined limits. 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.24: app/models/user.rb 2 # Generated code for the User model. 3 class User < ActiveRecord::Base 4 end # method User 41 Outline app/models/user .rb 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.25: app/controllers/users_controller.rb 2 # UsersController provides validation functionality for the table. 3 class UsersController < ApplicationController 4 # create a new User object 5 def admin 6 42 The admin action creates a new User @user = User.new # create a new User object 7 8 end # method admin 9 10 # validate that user exists def validate 11 12 13 14 # find a user with the correct name and password @user = User.find_by_name_and_password( params[ :user ][ :name ], params[ :user ][ :password ] ) 15 16 17 18 19 20 if ( @user == nil ) # if the user dosn’t exist redirect_to :action => "admin" # redirect to admin action else # user does exist session[ :user ] = @user # store the user in a session variable redirect_to :controller => "forums", :action => "index" end # if 21 22 23 end # method validate 24 def logout Outline app/controllers/ users_controller .rb The validate action implements a login attempt If the login is successful, store the User object in a session variable # log user out 25 reset_session # delete all session variables 26 redirect_to :controller => "forums", :action => "index" # redirect 27 end # method logout 28 end # class UserController 2008 Pearson Education, Inc. All rights reserved. 43 Performance Tip 24.1 Storing full objects in the session is inefficient. The user object is one of the rare exceptions, because it doesn’t change very often and is frequently needed in web applications that manage the state information for unique clients. 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.26: app/views/users/admin.rhtml --> 2 <!-- Login form used to send data to the user controller. --> 3 <h1>Please Log In</h1> 4 <% form_tag :action => 'validate' do %> <!-- create form tag --> 5 <p><label for="user_name">Name</label><br/> 6 <%= text_field 'user', 'name' 44 %></p> <!-- create input tag --> Outline The login form submits to the validate action, where the login information is processed app/views/users/ admin.rhtml 7 8 <p><label for="user_password">Password</label><br/> 9 <%= password_field 'user', 'password' 10 <%= submit_tag "Sign In" %> <!-- create submit tag --> 11 <% end %> <!-- create an end form tag --> %></p> <!-- create input tag --> Both fields specify a model and a column to which they correspond 2008 Pearson Education, Inc. All rights reserved. 1 <?xml version = "1.0" encoding = "utf-8"?> 2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 3 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 45 Outline 4 5 <!-- Fig. 24.27: app/views/layouts/users.rhtml--> 6 <!-- Display the name of the current action in the title bar --> 7 <html xmlns = "http://www.w3.org/1999/xhtml"> 8 <head> 9 app/views/ layouts/users .rhtml <title>Users: <%= controller.action_name %></title> 10 </head> 11 <body> 12 <%= yield %> 13 </body> 14 </html> 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.28: db/migrate/002_create_messages.rb 2 # Database migration script modified to add data to the table. 3 class CreateMessages < ActiveRecord::Migration 4 # create and configure messages table 5 6 def self.up create_table :messages, do |t| 7 8 t.column :title, :string, :limit => 64 t.column :author, :string, :limit => 20 9 t.column :created_on, :timestamp 10 11 t.column :email, :string, :limit => 40 t.column :message, :text 12 13 t.column :forum_id, :integer end # do block 14 15 16 Message.create :title => "Welcome to the Fourth Edition", :author => "Bob Green", 17 18 46 Outline db/migrate/002_ create_messages .rb :email => "[email protected]", :message => "We hope you enjoy the book.", 19 20 21 :forum_id => 2 end # method self.up 22 23 # remove messages table def self.down 24 drop_table :messages 25 end # method self.down 26 end # class CreateForums 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.29: app/models/message.rb 2 # Message Model containing validation and initialization functionality. 3 class Message < ActiveRecord::Base 4 belongs_to :forum # adds a forum method to Message 5 47 Specify that each Message belongs to a Forum 6 # validators (validates automatically before ActiveRecord.save) 7 validates_presence_of :title, :author, :email, :message 8 validates_format_of :email, 9 Outline app/models/ message.rb :with => /^([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})$/i 10 end # class Message Validators make sure that a Message is not created unless the title, author, email, and message are defined, and the email is properly formatted 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.30 db/migrate/003_create_forums.rb 2 # Database migration script modified to add data to the table. 3 4 class CreateForums < ActiveRecord::Migration # Create and configure forums table 5 6 7 8 def self.up create_table :forums do |t| t.column :name, :string, :limit => 64 t.column :administrator, :string, :limit => 20 9 10 11 t.column :created_on, :timestamp end # do block 12 13 Forum.create :name => "Ruby On Rails", :administrator => "user1" 14 15 Forum.create :name => "Internet and World Wide Web: 4th Edition", :administrator => "user1" 16 17 48 Outline db/migrate/003_ create_forums.rb end # method self.up 18 # remove forums table 19 def self.down 20 drop_table :forums 21 end # method self.down 22 end # class CreateForums 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.31: app/models/forum.rb 2 # Forum model that includes validation and initialization functionality. 3 class Forum < ActiveRecord::Base 49 4 has_many :messages, :dependent => :destroy 5 validates_presence_of :name 6 Outline app/models/forum .rb end # class Forum A forum model is a container for multiple message objects When a forum is destroyed, all of its messages are destroyed with it 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.32: app/controllers/forums_controller.rb 2 # ForumsController implements CRUD functionality. 3 class ForumsController < ApplicationController 4 5 50 Outline verify :method => :post, :only => [ :destroy, :create ], :redirect_to => { :action => :list } 6 7 8 9 10 # shortcut to the list method def index list render :action => 'list' 11 12 13 14 end # method index 15 16 17 18 19 20 @forums = Forum.find( :all ) end # method list 21 22 23 app/controllers/ forums_ controller.rb Ensure that anything modifying the database is sent to the server (1 of 2) as a POST request # set up the list web page that lists all forums def list Go back to the list page once a change has been submitted # set up the new web page that adds a new forum def new if ( session[ :user ] == nil ) # if user is not logged in Use flash to display an error at the top of the page if the user is not logged in flash[ :error ] = 'you must be logged in to complete this action' redirect_to :action => "index" and return end # if 24 25 26 27 28 @forum = Forum.new end # method new # attempt to create a new forum with the parameters passed in 2008 Pearson Education, Inc. All rights reserved. 29 30 31 32 33 def create @forum = Forum.new( params[ :forum ] ) 51 Outline @forum.administrator = session[ :user ].name if @forum.save # if save method was successful 34 35 36 37 38 39 40 flash[ :notice ] = 'Forum was successfully created.' redirect_to :action => 'list' else # save was unsuccessful render :action => 'new' # go to new Notify the user that their end # if...else action was successful end # method create 41 42 43 44 45 # set up the delete web page def delete if ( session[ :user ] == nil ) # if user is not logged in flash[ :error ] = 'you must be logged in to complete this action' redirect_to :action => "index" and return 46 47 48 49 50 51 52 53 54 else @forums = Forum.find( :all, :conditions => "administrator = '#{ session[:user].name }'" ) end # if else end # method delete # delete a forum with a specified parameter def destroy # find the forum and delete it app/controllers/ forums_ controller.rb (2 of 2) Only allow the user to see a list of forums to delete if the user is an administrator Delete a forum and redirect to the list page 55 Forum.destroy( params[ :forum ][ :id ] ) # delete the forum 56 redirect_to :action => 'list' # redirect to list 57 end # method destroy 58 end # class ForumsController 2008 Pearson Education, Inc. All rights reserved. 1 2 <!-- Fig. 24.33: app/views/forums/list.rhtml --> <!-- Template for the list action that displays a list of forums. --> 3 4 <h1>Deitel Message Forums</h1> <h2>Available Forums</h2> 5 6 7 8 9 <ul> <% for forum in @forums %> <!-- create a list item for every forum --> <li> <!-- link to list action in messages --> 10 11 12 13 52 Outline Use the @forums array (defined in the controller) to app/views/forums create a list of all <%= link_to ( forum.name, {:controller => 'messages', :action => 'list', :forum_id => forum.id}, { :class => (forum.created_on < 5.minutes.ago ? /list.rhtml (1 of 2) 'recent': nil ) } ) %> 14 </li> 15 <% end %> <!-- end for --> 16 </ul> 17 <% if ( session[ :user ] ) then %> 18 <!-- a user is logged in --> 19 20 21 22 <h2>Forum Management</h2> <ul> <li><%= link_to 'Add a Forum', :action => 'new' %></li> <li><%= link_to 'Delete a Forum', :action => 'delete' %></li> 23 </ul> 24 <% end %> <!-- end if --> 2008 Pearson Education, Inc. All rights reserved. 53 Outline app/views/forums /list.rhtml (2 of 2) 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.34 app/views/forums/new.rhtml --> 2 <!-- Template for a new action that adds a forum to the forums table. --> 3 <h1>New forum</h1> 4 <% form_tag :action => 'create' do %> 5 <%= render :partial => 'form' %> 6 <%= submit_tag "Create" %> 7 <% end %> 54 Outline app/views/forums /new.rhtml 8 9 <%= link_to 'Back', :action => 'list' %> The render :partial method inserts the contents of a partial file (in this case _form.rhtml) into a document 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.35: app/views/forums/_form.rhtml --> 2 <!-- Partial that contains a form used to add a new forum. --> 3 <%= error_messages_for 'forum' %> 4 <p><label for="forum_name">Name</label><br/> 5 <%= text_field 'forum', 'name' 55 Outline %></p> app/views/forums /_form.rhtml 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.36: app/views/forums/delete.rhtml --> 2 <!-- Template for delete action used to delete a Forum. --> 3 <h1>Delete a Forum</h1><br /> 56 Outline 4 5 <% form_tag :action => :destroy do %> <!-- create from tag --> 6 <p><label for="forum_id">Forum Name</label><br /> 7 <%= collection_select "forum", "id", @forums, "id", "name" %></p> 8 <%= submit_tag "Delete" %> <!-- create submit tag --> 9 <% end %> <!-- create end form tag --> 10 11 <%= link_to 'Back', :action => 'list' %> <!-- link back to list app/views/forums /delete.rhtml Use the collection_select method to generate a dropdown method --> menu from the @forms array. 2008 Pearson Education, Inc. All rights reserved. 1 <?xml version = "1.0" encoding = "utf-8"?> 2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 3 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 57 Outline 4 5 <!-- Fig. 24.37: app/views/layouts/forums.rhtml --> 6 <!-- Layout that displays the logged-in user for every Forums action. --> 7 <html xmlns = "http://www.w3.org/1999/xhtml"> 8 <head> 9 <title>Forums: <%= controller.action_name %></title> 10 <%= stylesheet_link_tag 'scaffold' %> <!-- link to a stylesheet --> app/views/layouts /forums.rhtml (1 to 2) 11 </head> 12 <body> 13 14 15 <div style = "text-align: right"> <% if ( session[ :user ] ) then %> <!-- if user is logged on --> <!-- code to display if user is logged on --> 2008 Pearson Education, Inc. All rights reserved. 16 <%= "Logged In As #{ session[ :user ].name }: " %> 17 <%= link_to 'Log Out', :controller => 'users', :action => 'logout' %> 18 19 Outline <% else %> <!-- user is not logged on --> 20 <!-- code to display if user is not logged on --> 21 <%= "Not Currently Logged In:" %> 22 <%= link_to 'Log In', app/views/layouts /forums.rhtml :controller => 'users', :action => 'admin' %> 23 24 58 <% end %> <!-- end if --> 25 </div> 26 <p style="color: green"><%= flash[ :notice ] %></p> 27 <p style="color: red"><%= flash[ :error ] %></p> (2 to 2) Link to the admin action to allow the user to login 28 29 <%= yield %> <!-- displays template --> 30 </body> 31 </html> 2008 Pearson Education, Inc. All rights reserved. 1 2 # Fig. 24.38: app/controllers/messages_controller.rb # MessagesController that implements CRUD functionality. 3 4 class MessagesController < ApplicationController verify :method => :post, :only => [ :destroy, :create ], 5 6 7 8 59 Outline :redirect_to => { :action => :list } app/controllers/ messages_ controller.rb # sets up the list web page that lists all messages def list 9 10 11 if ( params[ :forum_id ] ) # if parameter forum_id is provided session[ :forum_id ] = params[ :forum_id ] end # if 12 13 if ( session[ :forum_id ] == nil ) # if no forum_id is provided 14 15 16 flash[ :notice ] = 'there has been an error.' redirect_to :controller => "forums", :action => "list" and return end # if 17 18 @messages = Message.find( :all, :order => "created_on desc", 19 20 :conditions => "forum_id = #{ session[:forum_id ] }" ) @forum = Forum.find( :first, 21 22 23 :conditions => "id = #{ session[ :forum_id ] }" ) end # method list (1 to 2) Get an array of messages belonging to the forum with the forum_id stored in the session object for the list action 2008 Pearson Education, Inc. All rights reserved. 24 # sets up the new web page that creates a message 25 def new 26 @message = Message.new 27 28 end # method new 29 30 31 # attempts to create a new message with the parameters passed in def create @message = Message.new( params[ :message ] ) 32 33 34 35 36 37 38 39 40 @message.forum_id = session[ :forum_id ] if @message.save # if save method was successful 60 Outline app/controllers/ messages_ controller.rb (2 to 2) flash[ :notice ] = 'Message was successfully created.' redirect_to :action => 'list' else # save was unsuccessful render :action => 'new' end # if end # method create 41 end # class MessagesController 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.39: app/views/messages/list.rhtml --> 2 <!-- Template for the list action that displays a list of Forums. --> 3 4 <div style = "text-align: center"> <table style = "width: 600px; margin: 0 auto 0 auto"> 5 <tr class="msgHeader"> 6 7 8 <td><%= @forum.name %></td> </tr> <% for message in @messages %> 9 <!-- create two table rows for every message --> 10 11 12 <tr class="msgTitle"> <td> <strong><%= message[ 'title' ] %></strong><br /> 13 14 15 16 17 18 61 Outline app/views/ messages/list .rhtml (1 to 2) by <em><%= message[ 'author' ] %></em> at <%= message[ 'created_on' ].strftime("%m/%d/%Y at %I:%M%p") %> </td> </tr> Format the creation time using <tr class="msgPost"> the strftime method of the <!-- message content --> 19 20 21 22 <td><%= message[ 'message' ] %></td> </tr> <% end %> </table> 23 24 <%= link_to 'New message', :action => 'new' %> | Time object stored in message[‘created_on’] 25 <%= link_to 'list forums', 26 :controller => 'forums', :action => 'index' %> 27 </div> 2008 Pearson Education, Inc. All rights reserved. 62 Outline app/views/ messages/list .rhtml (2 to 2) 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.40: app/views/messages/_form.rhtml --> 2 <!-- A form that allows the user to enter a new message. --> 3 4 <%= error_messages_for 'message' %> 5 6 <table> <tr class = "alignRight"> 7 8 <td>Title</td> <td><%= text_field 'message', 'title' %></td> 9 10 11 </tr> <tr class = "alignRight"> <td>Author</td> 12 13 <td><%= text_field 'message', 'author' %></td> </tr> 14 15 <tr class = "alignRight"> <td>Email</td> 16 17 <td><%= text_field 'message', 'email' </tr> 63 Outline app/views/ messages/_form .rhtml (1 to 2) %></td> 18 <tr><td colspan = "2">Message</td></tr> 19 <tr><td colspan = "2"> 20 <%= text_area 'message', 'message', :cols => "30", :rows => "4"%> 21 </td></tr> 22 </table> The text_area method generates a textarea XHTML element 2008 Pearson Education, Inc. All rights reserved. 64 Outline app/views/ messages/_form .rhtml (2 to 2) 2008 Pearson Education, Inc. All rights reserved. 1 <?xml version = "1.0" encoding = "utf-8"?> 2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 3 65 Outline "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 4 5 <!-- Fig. 24.41: app/views/layouts/messages.rhtml --> 6 <!-- Message layout that links a style sheet and displays a message. --> 7 <html xmlns = "http://www.w3.org/1999/xhtml"> 8 <head> 9 <title>Messages: <%= controller.action_name %></title> 10 <%= stylesheet_link_tag 'scaffold' %> 11 </head> 12 <body> 13 14 <% if ( flash[ :notice ] ) then %> <p style="color: green"><%= flash[ :notice ] %></p> 15 <% end %> 16 <%= yield %> app/views/ layouts/messages .rhtml The stylesheet_link_tag generates a link element to an external style sheet—in this case, scaffold.css—in public/stylesheets/ 17 </body> 18 </html> 2008 Pearson Education, Inc. All rights reserved. 1 <?xml version = "1.0" encoding = "utf-8"?> 2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 3 66 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> Outline 4 5 <!-- Fig. 24.42: app/views/layouts/forums.rhtml --> 6 <!-- Forums layout that uses the default JavaScript libraries. --> 7 <html xmlns = "http://www.w3.org/1999/xhtml"> 8 <head> 9 <title>Forums: <%= controller.action_name %></title> 10 <%= stylesheet_link_tag 'scaffold' %> <!-- link to a stylesheet --> 11 <%= javascript_include_tag :defaults %> 12 </head> 13 <body> 14 15 <div style = "text-align: right"> app/views/ layouts/forums .rhtml (1 to 2) Include the default JavaScript libraries, including Script.aculo.us and Prototype <% if ( session[ :user ] ) then %> <!-- if user is logged on --> 2008 Pearson Education, Inc. All rights reserved. 16 <!-- code to display if user is logged on --> 17 <%= "Logged In As #{ session[ :user ].name }: " %> 18 <%= link_to 'Log Out', <% else %> <!-- user is not logged on --> 21 <!-- code to display if user is not logged on --> 22 <%= "Not Currently Logged In:" %> 23 <%= link_to 'Log In', app/views/ layouts/forums .rhtml :controller => 'users', :action => 'admin' %> 24 25 Outline :controller => 'users', :action => 'logout' %> 19 20 67 <% end %> <!-- end if --> 26 </div> 27 <p style="color: green"><%= flash[ :notice ] %></p> 28 <p style="color: red"><%= flash[ :error ] %></p> (2 to 2) 29 30 <%= yield %> <!-- displays template --> 31 </body> 32 </html> 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.43: app/views/forums/list.rhtml --> 2 <!-- Displaying a list of messages without reloading the page. --> 3 4 <h1>Deitel Message Forums</h1> <div class = "forumList"> 5 <h2>Available Forums</h2> 6 7 8 <ul> <% for forum in @forums %> <li> 10 11 12 { :url => { :controller => 'messages', :action => 'list', :forum_id => forum.id }, :update => 'currentForum' }, 13 { :class => ( forum.created_on < 5.minutes.ago ? 14 15 16 17 18 'recent': nil ) } ) %> 23 24 Outline app/views/forums /list.rhtml <%= link_to_remote ( forum.name, 9 19 20 21 22 68 (1 to 2) The link to each forum makes an Ajax call, displaying the selected forum’s messages in the currentForum div using a partial page update </li> <% end %> </ul> <% if ( session[ :user ] ) then %> <h2>Forum Management</h2> <ul> <li><%= link_to 'Add a Forum', :action => 'new' %></li> <li><%= link_to 'Delete a Forum', :action => 'delete' %></li> </ul> <% end %> 25 </div> 26 <div id = 'currentForum' class = "ajaxComponent"> 27 </div> Messages are displayed in this div 2008 Pearson Education, Inc. All rights reserved. 69 Outline app/views/forums /list.rhtml (2 to 2) 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.44: app/views/messages/list.rhtml --> 2 <!-- Forum that allows the user to add a message on the same page. --> 3 <div class = "messageList"> 4 <table style = "width: 400"> 5 <tr class="msgHeader"> 6 <td><%= @forum.name %></td> 7 </tr> 8 <% for message in @messages %> 9 <tr class="msgTitle"> 10 <td> 11 <strong><%= message.title %></strong><br/> 12 by <em><%= message.author %></em> at 13 14 15 16 17 70 Outline app/views/ messages/list .rhtml (1 to 2) <%= message.created_on.strftime( "%m/%d/%Y at %I:%M%p" ) %> </td> </tr> <tr class="msgPost"> <td><%= message.message %></td> 18 </tr> 19 <% end %> 20 </table> 21 22 <%= link_to_remote 'New message', 23 :url => { :action => 'new' }, 24 :update => 'currentForum'%> 25 </div> The New Message link puts the form in on the same page using a partial page update 2008 Pearson Education, Inc. All rights reserved. 71 Outline app/views/ messages/list .rhtml (2 to 2) 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.45: app/views/messages/new.rhtml --> 2 <!-- Allows the user to add a new message without reloading the page. --> 3 <%= form_remote_tag :url=> { :action => 'create' }, 4 :update => 'currentForum' %> 5 <%= render :partial => 'form' %> 6 <%= submit_tag "Create" %> 7 <%= end_form_tag %> 8 <%= link_to_remote 'Cancel', :url=> { :action => 'list' }, 9 72 Outline Forum creation is also done without reloading the entire app/views/ page messages/new .rhtml :update => 'currentForum' %> Canceling forum (1 tocreation 2) replaces the form with the list of forums 2008 Pearson Education, Inc. All rights reserved. 73 Outline app/views/ messages/new .rhtml (2 to 2) 2008 Pearson Education, Inc. All rights reserved. 74 24.7 Script.aculo.us • Script.aculo.us allows you to easily create visual effects similar to those in Adobe Flash and Microsoft Silverlight. • The library provides many pre-defined effects, as well as the ability to create your own effects from the pre-defined ones. • The Script.aculo.us library also provides drag-and-drop capability through the draggable_element and drop_receiving_element methods. • The sortable_element method allows you to describe a list that allows the user to drag and drop list items to reorder them. • Script.aculo.us also provides the text_field_with_auto_complete method, which enables server-side autocompletion of a text field. 2008 Pearson Education, Inc. All rights reserved. 75 Fig. 24.46 | Script.aculo.us’s Fade effect. 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.47: app/views/scriptaculous_demo/index.rhtml --> 2 <!-- Default view for Script.aculo.us demo. --> 3 <div id = "link"> 4 :effect_index => 0}, :update => "link", 6 :before => visual_effect( :Shrink, 'image', :duration => 1.0, :queue => 'end') %> 7 </div> 9 10 <div id = "image" style = "width: 244px; height: 320px;"> 11 Outline <%= link_to_remote 'Shrink', :url => {:action => 'playEffect', 5 8 76 <%= image_tag "jhtp7medium.jpg" %> 12 </div> app/views/ scriptaculous_ demo/index.rhtml Play a Shrink effect on the image div before proceeding to the playEffect action 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.48: app/controllers/scriptaculous_demo_controller.rb 2 # Script.aculo.us Demo controller 3 class ScriptaculousDemoController < ApplicationController 4 Outline def index @currentEffect = 0 5 6 end 7 def playEffect 8 @currentEffect = params[ :effect_index ] 9 render :partial => "link" 10 77 app/controllers/ scriptaculous_ demo_controller .rb end # method playEffect 11 end # class ScriptaculousDemoController 2008 Pearson Education, Inc. All rights reserved. 1 <?xml version = "1.0" encoding = "utf-8"?> 2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 3 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 78 Outline 4 5 <!-- Fig. 24.49: app/views/layouts/application.rhtml --> 6 <!-- Default layout of Script.aculo.us demo. --> 7 <html xmlns = "http://www.w3.org/1999/xhtml"> 8 <head> 9 <title>Script.aculo.us Effects Demo</title> 10 <%= javascript_include_tag :defaults %> 11 </head> 12 <body> 13 14 app/views/layouts /application .rhtml <%= yield %> </body> 15 </html> 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.50: app/views/scriptaculous_demo/_link.rhtml --> 2 <!-- link partial view for Script.aculo.us demo --> 3 <!-- Grow effect --> 4 5 <% if @currentEffect == '0' %> <%= link_to_remote 'Grow', :url => { :action => 'playEffect', 6 :effect_index => 1 }, :update => "link", 7 :before => ( visual_effect( 8 :Grow, 'image', :duration => 1.0, :queue => 'end' ) ) %> 9 10 <!-- Fade effect --> 11 <% elsif @currentEffect == '1' %> 12 <%= link_to_remote 'Fade', :url => { :action => 'playEffect', 13 14 15 79 Outline app/views/ scriptaculous_ demo/_link.rhtml (1 to 5) :effect_index => 2 }, :update => "link", :before => ( visual_effect( :Fade, 'image', :duration => 1.0, :queue => 'end' ) ) %> 16 17 <!-- Appear effect --> 18 <% elsif @currentEffect == '2' %> 19 <%= link_to_remote 'Appear', :url => {:action => 'playEffect', 20 :effect_index => 3 }, :update => "link", 21 :before => ( visual_effect( 22 :Appear, 'image', :duration => 1.0, :queue => 'end' ) ) %> 23 24 <!-- BlindUp effect --> 25 <% elsif @currentEffect == '3' %> 26 <%= link_to_remote 'BlindUp', :url => { :action => 'playEffect', 27 :effect_index => 4 }, :update => "link", 28 :before => ( visual_effect( 29 :BlindUp, 'image', :duration => 1.0, :queue => 'end' ) ) %> 30 2008 Pearson Education, Inc. All rights reserved. 31 <!-- BlindDown effect --> 32 <% elsif @currentEffect == '4' %> 33 34 35 <%= link_to_remote 'BlindDown', :url => { :action => 'playEffect', :effect_index => 5 }, :update => "link", 41 42 43 44 Outline :before => ( visual_effect( 36 :BlindDown, 'image', :duration => 1.0, :queue => 'end' ) ) %> 37 38 <!-- Puff effect --> 39 <% elsif @currentEffect == '5' %> 40 80 <%= link_to_remote 'Puff', :url => { :action => 'playEffect', :effect_index => 6 }, :update => "link", :before => ( visual_effect( app/views/ scriptaculous_ demo/_link.rhtml (2 to 5) :Puff, 'image', :duration => 1.0, :queue => 'end' ) ) %> 45 <!-- SwitchOff effect --> 46 <% elsif @currentEffect == '6' %> 47 <%= link_to_remote 'SwitchOff', :url => { :action => 'playEffect', 48 49 50 :effect_index => 7 }, :update => "link", :before => ( visual_effect( :SwitchOff, 'image', :duration => 1.0, :queue => 'end' ) ) %> 51 52 <!-- SlideUp effect --> 53 <% elsif @currentEffect == '7' %> 54 55 56 57 <%= link_to_remote 'SlideUp', :url => { :action => 'playEffect', :effect_index => 8 }, :update => "link", :before => ( visual_effect( :SlideUp, 'image', :duration => 1.0, :queue => 'end' ) ) %> 58 2008 Pearson Education, Inc. All rights reserved. 59 <!-- SlideDown effect --> 60 <% elsif @currentEffect == '8' %> 61 62 63 <%= link_to_remote 'SlideDown', :url => { :action => 'playEffect', :effect_index => 9 }, :update => "link", 69 70 71 72 Outline :before => ( visual_effect( 64 :SlideDown, 'image', :duration => 1.0, :queue => 'end' ) ) %> 65 66 <!-- Shake effect --> 67 <% elsif @currentEffect == '9' %> 68 81 <%= link_to_remote 'Shake', :url => { :action => 'playEffect', :effect_index => 10 }, :update => "link", :before => ( visual_effect( app/views/ scriptaculous_ demo/_link.rhtml (3 to 5) :Shake, 'image', :duration => 1.0, :queue => 'end' ) ) %> 73 <!-- Pulsate effect --> 74 <% elsif @currentEffect == '10' %> 75 <%= link_to_remote 'Pulsate', :url => { :action => 'playEffect', 76 77 78 :effect_index => 11 }, :update => "link", :before => ( visual_effect( :Pulsate, 'image', :duration => 1.0, :queue => 'end' ) ) %> 79 80 <!-- Squish effect --> 81 <% elsif @currentEffect == '11' %> 82 83 84 85 <%= link_to_remote 'Squish', :url => { :action => 'playEffect', :effect_index => 12 }, :update => "link", :before => ( visual_effect( :Squish, 'image', :duration => 1.0, :queue => 'end' ) ) %> 86 2008 Pearson Education, Inc. All rights reserved. 87 <!-- Grow effect --> 88 <% elsif @currentEffect == '12' %> 89 90 91 <%= link_to_remote 'Grow', :url => { :action => 'playEffect', :effect_index => 13 }, :update => "link", 97 98 99 100 Outline :before => ( visual_effect( 92 :Grow, 'image', :duration => 1.0, :queue => 'end' ) ) %> 93 94 <!-- Fold effect --> 95 <% elsif @currentEffect == '13' %> 96 82 <%= link_to_remote 'Fold', :url => { :action => 'playEffect', :effect_index => 14 }, :update => "link", :before => ( visual_effect( app/views/ scriptaculous_ demo/_link.rhtml (4 to 5) :Fold, 'image', :duration => 1.0, :queue => 'end' ) ) %> 101 <!-- Grow effect --> 102 <% elsif @currentEffect == '14' %> 103 <%= link_to_remote 'Grow', :url => { :action => 'playEffect', 104 105 106 :effect_index => 15 }, :update => "link", :before => ( visual_effect( :Grow, 'image', :duration => 1.0, :queue => 'end' ) ) %> 107 108 <!-- DropOut effect --> 109 <% elsif @currentEffect == '15' %> 110 111 112 113 <%= link_to_remote 'DropOut', :url => { :action => 'playEffect', :effect_index => 16 }, :update => "link", :before => ( visual_effect( :DropOut, 'image', :duration => 1.0, :queue => 'end' ) ) %> 114 2008 Pearson Education, Inc. All rights reserved. 115 <!-- Grow effect --> 116 <% elsif @currentEffect == '16' %> 117 <%= link_to_remote 'Grow', :url => { :action => 'playEffect', 118 :effect_index => 17 }, :update => "link", 119 :before => ( visual_effect( 120 :Grow, 'image', :duration => 1.0, :queue => 'end' ) ) %> 121 122 <!-- Shrink effect --> 83 Outline app/views/ scriptaculous_ demo/_link.rhtml 123 <% elsif @currentEffect == '17' %> 124 <%= link_to_remote 'Shrink', :url => { :action => 'playEffect', 125 :effect_index => 0 }, :update => "link", 126 :before => ( visual_effect( 127 (5 to 5) :Shrink, 'image', :duration => 1.0, :queue => 'end' ) ) %> 128 <% end %> 2008 Pearson Education, Inc. All rights reserved. 84 Fig. 24.51 | Flickr Photo Viewer showing search results for bugs. 2008 Pearson Education, Inc. All rights reserved. 1 2 <?xml version = "1.0" encoding = "utf-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 3 4 5 <!-- Fig. 24.52: app/view/flickr/index.rhtml --> 6 <!-- Main view for Flickr Photo Viewer. --> 7 8 <html xmlns = "http://www.w3.org/1999/xhtml"> <head> 9 10 11 12 13 <title>Flickr Photo Viewer</title> <%= javascript_include_tag :defaults %> <%= stylesheet_link_tag 'flickrPhotoViewer' %> 85 Outline app/view/ flickr/index .rhtml (1 to 2) </head> <body> 14 <!-- Form to search for tags --> 15 16 <%= form_remote_tag :url => { :action => 'search' }, :update => 'thumbs', 17 18 :complete => visual_effect( :BlindDown, 'thumbs' ), :before => { visual_effect( :BlindUp, 'thumbs' ), 19 20 %( Element.show( 'loading' ) ) }, :failure => %( Element.hide( 'loading' ) ), 21 :success => %( Element.hide( 'loading' ) ) %> A form that searches for tags, using blind effects and a loading indicator 2008 Pearson Education, Inc. All rights reserved. <div id = "search"> 22 23 Tags: 24 <%= text_field_tag "tags" %> 25 #: 26 <%= text_field_tag "numImages", "8", :size => "3" %> 27 <%= submit_tag "Search" %> 28 <div id = "loading" style = "display: none">Loading...</div> 29 Outline app/view/ flickr/index .rhtml </div> 30 31 <%= end_form_tag %> 32 <div id = "thumbs"></div> 33 <div id = "fullsizeImage"></div> 34 86 (2 to 2) </body> 35 </html> 2008 Pearson Education, Inc. All rights reserved. 1 # Fig. 24.53: app/controllers/flickr_controller.rb 2 # Controller for Flickr Photo Viewer. 3 class FlickrController < ApplicationController 4 # handle the search request 5 def search 6 flickr = Flickr.new 7 render :partial => "thumbs", 8 :collection => flickr.photos( :tags => params[ :tags ], 9 :per_page => params[ :numImages ] ) 10 end # method search 11 12 # handle the thumbnail click, sets the currentURL variable 13 def fullsizeImage 14 15 87 Outline app/controllers/ flickr_ controller.rb Search for tags and display paginated results @currentURL = params[ :imageURL ] end # method fullsizeImage 16 end # class FlickrController 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.54: app/views/flickr/_thumbs.rhtml --> 2 <!-- thumbs view of Flickr Photo Viewer. --> 3 <%= link_to_remote image_tag( thumbs.sizes[ 0 ][ 'source' ], 4 5 6 Outline :class => "image" ), :url => { :action => 'fullsizeImage', :imageURL => thumbs.sizes[ 3 ][ 'source' ] }, 7 :update => "fullsizeImage", 8 :success => visual_effect( :grow, 'fullsizeImage', 9 88 app/views/flickr /_thumbs.rhtml :queue => 'last' ) %> Display a thumbnail that links to the full sized image 2008 Pearson Education, Inc. All rights reserved. 1 <!-- Fig. 24.55: app/views/flickr/fullsizeImage.rhtml --> 2 <!-- fullsizeImage view of Flickr Photo Viewer. --> 3 <%= image_tag( @currentURL, :class => "image" ) %> Display the full size version of an image 89 Outline app/views/flickr /fullsizeImage .rhtml 2008 Pearson Education, Inc. All rights reserved.