1. Ruby on Rails by Manik Juneja

2. Ruby on Rails by Manik Juneja
About Rails
Rails is a Web Application development framework.
Based on the MVC pattern
Gives a pure Ruby development environment
Created by DHH of 37signals.
Is open source
Some sites running on RoR are basecamp, tadalist, writeboard, Campfire, 43things, odeo, Blinksale, Bubbleshare, Calendarhub, Nativetext, Numsum, Sproutit, Suprglu
Some open source applications built on RoR are typo, hieraki2
Ruby on Rails by Manik Juneja

3. Ruby on Rails by Manik Juneja
Rail’s Philosophy
DRY( Don’t Repeat Yourself)
Every piece of knowledge should be expressed in just one place
Convention over configuration
Sensible defaults for just about every aspect of your application. If you need to overwrite the convention Rails makes that easy too.
The MVC architecture
Ruby on Rails by Manik Juneja

4. Ruby on Rails by Manik Juneja
What is a Model?
Model stores the state of the application
Sometime this state is
Transient (Session)
Permanent (database)
Model = data + business rules that apply to it.
Ruby on Rails by Manik Juneja

5. Model: Object Relational Mapping
DB is relational
Ruby is Object Oriented
Table
Class
Row
Object
Columns
Attributes
Table Level operations
Class Methods
Row Level operations
Object Methods
ActiveRecord Module provides ORM in Rails.
Ruby on Rails by Manik Juneja

6. ActiveRecord: Getting Started
Specify database access details in config/database.yml file
Create a subclass of ActiveRecord::Base class
Give it a name. (By default, Active Record assumes that the name of the table is the plural form of the name of the class. By default id is the primary key )
Ruby on Rails by Manik Juneja

7. ActiveRecord: Class methods
Class Methods ( = Table level operations)
Ruby on Rails by Manik Juneja

8. ActiveRecord: Instance methods
Ruby on Rails by Manik Juneja

9. ActiveRecord Relationships: one to many
Ruby on Rails by Manik Juneja

10. ActiveRecord Relationships: many to many
Ruby on Rails by Manik Juneja

11. ActiveRecord: Other Features
Transaction Handling
Acts as (list, tree)
Aggregation
Validation
Callback
etc
Ruby on Rails by Manik Juneja

12. ActionPack : where the action happens
Action Pack lies at the heart of Rails applications. It consists of two Ruby modules, ActionController and ActionView. Together, they provide support for processing incoming requests and generating outgoing responses.
Ruby on Rails by Manik Juneja

13. Ruby on Rails by Manik Juneja
ActionController
Controller orchestrates the application
Receives external input
Processes internal action
Responds to user
Receives external input
In the form of a url like
File config/routes.rb, is used to map external requests to internal actions.
controller
user
action
show id 1
Ruby on Rails by Manik Juneja

14. ActionController: action
Controller looks for a public instance method with the same name as the incoming action
Controller has access to the execution environment via objects such as request, params, response, cookies, session, header
Ruby on Rails by Manik Juneja

15. ActionController : filter
Filters enable wrapping of controllers’ actions — you can write a chunk of code once and have called before or after any number of actions in your controller
This is very useful in authentication, logging etc.
Ruby on Rails by Manik Juneja

16. Ruby on Rails by Manik Juneja
ActionView
The ActionView module encapsulates the functionality needed to render templates.
A Template is text embedded with ruby code ( in erb tags <% ….. %>
All instance variables of the controller are available in the template.
Ruby on Rails by Manik Juneja

17. Layouts, Partials, Components
Honoring DRY
Many pages share the same header, footer, sidebar (use layouts)
Multiple pages may contain same snippet of rendered HTML (use partials)
Same functionality may appear on multiple pages ( use components )
Ruby on Rails by Manik Juneja

18. Ruby on Rails by Manik Juneja
Pagination
Rails has inbuilt pagination support at both controller and view level
Ruby on Rails by Manik Juneja

19. Ruby on Rails by Manik Juneja
Ajax on Rails
Rails has inbuilt support for Ajax
It has prototype, effects, drag drop and control JavaScript libraries built in.
JavaScriptHelper module which wrap JavaScript access in ruby code.
Ruby on Rails by Manik Juneja

20. Must Mention, before I Thank You
Action Mailer
Action Web Service
Testing Framework
Rake
Ruby on Rails by Manik Juneja

21. Ruby on Rails by Manik Juneja
THANK YOU
Ruby on Rails by Manik Juneja