Ruby on Rails

1
Ruby on Rails

• Micah Ernst

2
Outline

• Overview
• What is Ruby?
• What is Rails?
• Requirements
• What do I need?
• Advantages
• Why do I want it?
• Questions

3
Overview

• Ruby is a Object-Oriented programming language
• Rails is a web application framework

4
Ruby - About

• TRUE Object Oriented Language
• Interpreted/Scripted Language
• Similar Use and Features as Perl
• Process text files
• System Management
• Extensible Portable

5
Ruby - Principles

• Principle of least surprise
• Arraysize or Arraylength?
• Same method theyre aliased
• What are the differences between arrays?
• difference array1 array2
• union array1 array2

6
Ruby - Principles

• Principle of Least Effort
• We dont want to waste time
• Rapid Application development
• Acessors/Mutators are created for you
• The quicker we can program something the more we
  can accomplish
• Less code means less bugs
• Less code also means easier to understand,
  maintain, and enhance

7
Ruby - Variables

• No more public, private, protected
• _at_var ? Instance Variable
• Var ? Local Variable
• var ? Global Variable

8
Ruby - Naming Conventions

• All Variables Are Lowercase
• No camelCase only under_score
• Constants are ALL_CAPS

9
Rails - History

• David Heinemeier Hansson (37signals)
• Extracted from Basecamp project
• First released to public in July 2004
• Version 1.0 was released December 13, 2005

10
Rails - About

• Based on a Model-View-Controller (MVC)
  architecture

11
Rails - MVC

• Model
• Classes representing RDBMS tables
• Classes are handled through the ActiveRecord
• View
• How data from the Controller is displayed
• HTML templates
• Controller
• Responds to user interaction
• Manipulates data in Model and displays it through
  the View
• Initiated by a user through a web browser

12
Ruby on Rails - Principles

• Dont Repeat Yourself
• Definitions only need to be made once
• Once a definition is made, Ruby can find the rest
  of the information itself
• Example Column names do not need to be defined
  in ActiveRecord because Ruby can find them from
  the database itself
• Convention over Configuration
• No XML configuration files!
• Programmer only needs to define what is
  unconventional
• Example Class Post corresponds to database
  table post.

13
Requirements

• FastCGI-capable web server
• Apache 1.3.x or 2.x
• lighttpd
• Database and driver
• MySQL or SQLite for example

14
Advantages

• Open Source (FREE!)
• Use, copy, modify, distribute
• No need to write SQL
• Works with a variety of database types
• MySQL
• PostgreSQL
• SQLite
• IBM DB2
• Oracle
• Microsoft SQL Server
• Package includes WEBrick web server for
  development and testing
• Rails provides helpers for implementing AJAX
  applications

15
Questions?