This document provides an overview of using Ruby on Rails and AJAX for building a social networking application. Some key points covered include: - Why Rails is useful for rapid application development and its model-view-controller framework. - How to quickly generate scaffolding and models to create the basic structure and relationships of users, communities, posts, and other elements. - Techniques for AJAXifying forms and adding features like in-place editing with libraries like script.aculo.us. - Best practices for defining relationships between models and using those relationships to retrieve and display related data. - Additional topics covered include transactions, tagging, blog integration, and resources for further learning.

1. Applied Ruby on Rails & AJAX An insight into the technology and principles behind a social networking community

2. Who am I? Farhan Mashraqi (Frank Mash) Developer for 7+ years MySQL DBA Community Member A Recovering PHP Developer Contact Information: Business E-mail: [email_address] Personal E-mail: [email_address] Personal Blog http://mashraqi.com

3. What we’ll cover (aka the essentials) Why ROR? MVC Crash Course (Scaffolding etc) URLs in ROR Adoppt AJAXifying Forms Relationships / Validations

4. The essentials continued Transactions Blog Claims Tagging In place editing Learn more Q&A

5. Why would I use Ruby On Rails? RAD DRY: “Do not Repeat Yourself” Disciplined Normalization Relationships Web Services Everything is an Object

6. MVC

7. Crash Course [root@srv31 docs]# rails ror create create app/controllers create app/helpers create app/models create app/views/layouts create config/environments create components create db create doc create lib create lib/tasks create log create public/images ... Creating a bare application on Rails [root@srv31 docs]# rails ror

8. Do it with Scaffolding [root@srv31 ror]# ruby script/generate scaffold user exists app/controllers/ exists app/helpers/ create app/views/users exists test/functional/ dependency model exists app/models/ exists test/unit/ exists test/fixtures/ create app/models/user.rb ruby script/generate scaffold user CRUD = ‘C’reate, ‘R’ead, ‘U’pdate, ‘D’elete

9. Experience the magic http://localhost:3000/users http://localhost:3000/users/new

10. Find functions find_by_[field_name] (field_value) find_by_[field_name]_and_[field_name] find_first find_all_by find() find_by_sql(‘SELECT ….’)

11. URLs in ROR <%= link_to “Reply”, :controller=>”posts”, :action=>“reply”, :id=>4 %>

12. What is Adoppt A replicatable social networking platform Create and participate in communities Blogs, Forums, Favorites and more

15. Ajaxifying the login form Ajaxified version <%= link_to “Login”, :controller=>”member”, :action=>”login” %> Typical form in ROR <%= link_to_remote “Login”, :url=>{ :controller=>”member”, :action=>”login” }, :update => “loginform”, :loading => “Element.toggle($(‘loading’))”, :complete => “Element.toggle($(‘loading’))” %> Same form ‘AJAXified’

17. Relationships / Validations A community Has many members subscribed Members can post favorite web sites Belongs to a member or system class Portal < ActiveRecord::Base has_many :subscriptions has_many :favorites belongs_to :member validates_presence_of :portal_name validates_presence_of :portal_description validates_presence_of :portal_url validates_uniqueness_of :portal_url … end

18. HABTM using Subscriptions class Member has_many :subscriptions end class Portal has_many :subscriptions end class Subscription belongs_to :member belongs_to :portal end

19. Self referential relationships A member has many friends (member) Self referential HABTM relationship class Member < ActiveRecord::Base has_and_belongs_to_many :friends, : class_name => &quot;Member&quot;, : join_table => &quot;friends_members&quot;, : association_foreign_key => &quot;friend_id&quot;, : foreign_key => &quot;member_id&quot;, : after_add => :become_friend_with_friend, : after_remove => :end_friendship end

20. Using relationships 1. Which favorites were posted to a portal @portal = Portal.new @favorites = @portal.favorites 2. Which members are subscribed? @portal = Portal.new @members = @portal.subscriptions @member = Member.new @member_portals = @member.portals 3. Which portals a member is subscribed to? 4. Which members are friends of a member? @member = Member.new @friends = @member.friends

21. Transactions (InnoDB) Member.transaction(@member, @friend) do @member.friends << @friend unless @member.friends.include?(@friend) @friend.friends << @member unless @friend.friends.include?(@member) end

22. Blog Claims def claim_verify @wb= Weblog.find_by_url(@params[:url]) require 'open-uri‘ @found = open(@wb.url).read.include?(@wb.v_key) end

23. Tagging acts_as_taggable gem (http://taggable.rubyforge.org/)

24. Tagging class Article < ActiveRecord::Base acts_as_taggable :join_class_name => ' TagArticle ‘ class TagArticle belongs_to :article, :class_name => ' Article ', :foreign_key => 'article_id‘ @tagged = Article.tags_count(:limit => 10) Tagging an article @article = Article.new @article.tag “mysql conference ror” Tags for an article @tags = @article.tags() Tag Cloud (Tom Fakes)

25. In place editing class BlogsController < ApplicationController in_place_edit_for :weblog, :description <%= in_place_editor_field :weblog, :description, :value=>'' %> In your views file In your model

26. Recap ROR: Valuable to You

27. Where to learn more Books Agile Web Development with Rails by Dave Thomas and David Heinemeier Hansson Pro Rails by me ROR Recipes by Chad Fowler Websites http://www.ruby-doc.org/ http://www.rubygarden.org/ruby/ http://www.ruby-lang.org/ http://www.ruby-doc.org/stdlib/libdoc/rdoc/rdoc/index.html http://script.aculo.us http://rubyonrails.adoppt.com/blog/frank

28. Q&A