Ruby on Rails

1. Ruby on Rails Web development that doesn’t hurt

2. Ruby on Rails • Framework written in the Ruby programming language for database-backed web applications • Utilizes MVC design pattern • Created by David Heinemeier Hansson in mid 2003 and released in 2004 • Developed to create the Basecamp project management web application

3. Philosophy • Convention over configuration • Almost no configuration files • Helper scripts to get started • Conformity through freebies • Magic wiring relies on common structures due to conventions of Ruby on Rails • Best practices by invitation • Auto-generated unit and integration testing

4. Built-in Functions • Helper scripts • Create directory hierarchy and skeleton code • Create model, view and controller objects • Set up database connectivity • ActiveRecord • Dynamic method generation • Built-in WEBrick web server

5. Ruby • Object Oriented Scripting Language • Interpreted • Open Source • Fully OO that simulates procedurals • Created by Yukihiro Matsumoto (1993) • Publicly released in 1995 • New but well documented • Based loosely of Eiffel and Ada but heavily influenced by other languages like Perl, Python, Java/JavaScript, etc.

6. Reflective Language • Ruby incorporates many beneficial features of other languages • Flexible programming (Perl) • Built in regex (Perl) • Error and Exception Handling (Python, Java) • Mark and Sweep Garbage Collector (Java) • No variable declaration (Perl, PHP, etc) • Embedded doc tools, RDoc (Java) • No Semicolon ‘;’ ! (Python) • Key word parameters *faked* (Python) • And many others

7. Highlights: Open Classes • Every class, including the core classes can be modified at any time. • You just need to call Class class_name #modification code End • Example: #modding floats to output in currency class Float def to_m sprintf("$%.2f", self) end end

8. Highlights: Embedded Strings • In Perl and PHP you can embed variables into strings. In Ruby you can embed whole blocks of code into string. • Just need to put it between #{ } • Example: #print out the prices in currency format from an #array without the need to put it back into a #variable p = [1.25, 2.00, 3.15] print “Lily: #{p[0].to_m} Rose: #{p[1].to_m} Viola: #{p[2].to_m}”

9. Highlights: RHTML • Ruby can be directly embedded into HTML much like the way PHP does • Must have eruby (ERb) installed • Trigger ERb with <% %>, <% -%>, and <%= %> tags • Example: <b>Names of all the people</b> <% for person in @people %> Name: <%= person.name %><br/> <% end %>

10. Future of Ruby • Ruby is easy to learn, simple to understand and friendly to write in • It has become quite popular and gained a large following since its release • Ruby’s library is expanding rapidly with many modules currently being written for it. And with the soon to be release version 2.0 • Not to mention it is completely free • But will all this guarantee that the language won’t become obsolete once a new language comes out? • It is left to be seen, as the language is too new, and its support not enough to become a standard

11. Rails and the MVC Pattern • It is hard to develop with MVC in mind for most web applications using PHP/Perl/JSP. • Can be done, but requires a lot of work to create a framework to enforce the MVC pattern. • Although other frameworks already exist for Java (Struts), Perl (Maypole), and for PHP, they are not integrated deeply in their respective languages. This is bad because legacy systems may not be written with MVC in mind, resulting in spaghetti code.

12. Rails and the MVC Pattern • RoR integrates and enforces MVC in its framework. • Because of this most all applications written in RoR follow the MVC design pattern, and thus allowing for easier scalability and maintainability. • This significantly reduces the amount of repeated code. RoR was designed with the Don’t Repeat Yourself philosophy in mind.

13. Model • The Model in RoR wraps to represent the RDMBS tables used for a site. • A very minimal amount of configuration needs to be done. All that needs to be configured is to tell configure where the database is sitting and the login information. • Once the database is mapped, each table in the database is represented by its own class automatically. This allows ease of access without any further configuration. • Based on the Active Record pattern.

14. View • Uses embedded ruby code in .rhtml files. Similar to PHP and JSP. • <html> <head>..etc… <% Handle Ruby statements here in embedded. %> </body></html>

15. Controller • The controller handles the logic, and responds to user interaction and manipulates the model. • Out of the box, Rails provides the controller with prepackaged functions to easily perform CRUD (Create/Read/Update/Delete) operations on the model. No need to rewrite the same code over and again.

16. Putting it all together • RoR requires minimal configuration for implementing MVC. Once a new RoR project is created, the framework will automatically create the MVC components. Each component will map to each other with little configuration.

17. AJAX on Rails • Ability to incorporate AJAX (Asychronous JavaScript and XML) into Rails-driven sites • Contains the Prototype JavaScript library • Works with AJAX functions • Works with Script.aculo.us (additional functionality onto Prototype) • Contains helper functions for implementing AJAX • link_to_remote() • form_remote_tag() • observer_field()

18. AJAX on Rails • No longer a complicated process to incorporate AJAX onto Rails-driven sites • Newest version of Rails contains RJS • Integrated JavaScript templating language • Create JavaScript using Ruby • Use server-side variables to write JavaScript and update elements on the fly • Reduce the amount of code needed to implement AJAX

19. Applications and Projects • Applications • Instiki • TYPO • Web pages • DRTV Research • Penny Arcade

20. Applications: Instiki • Wiki-based program that focuses on ease of installation and simplicity in running • 2 step method for install • Simplistic user interface • Great for notes, brainstorming, organizing gatherings, file sharing, etc. • Created by David Heinemeier Hansson, creator of Ruby on Rails • Used for creating and editing web pages • RoR is the structure behind the code of Instiki • Used for database interaction, syntax interpretation, etc.

21. Applications: TYPO • TYPO is a free, open source (MIT License) blogging engine written in the Ruby programming languge, using the Ruby on Rails web application framework • Typo can use any of the various SQL databases supported by the Ruby on Rails framework • Features include: • Do not need to rebuild the contents of the blog; everything is created on the fly • Uses caching • Web-based administration and posting interface, plus support for all three major external client API’s (Blogger, MetaWeblog and MovableType Extensions)

22. Web pages: DRTV Research • DRTV Research is a free online application that combines television lineup listings per week with consumer demographic data for North America. • Over 700,000 pages of data are available on DRTV Research with new data added daily. • Ruby on rails provides the framework for the database interaction.

23. Web pages: Penny Arcade • Penny Arcade is among the most popular web-comics currently online, hosting both a children's charity (Child’s Play) and a gaming convention (PAX) each year. • Ruby on Rails framework used for the sites forums, and database interaction.

24. Ruby on Rails: Cons • Confined to one language: Ruby • Forced to one directory hierarchy • Not too popular (Though it is becoming more so recently) • Not yet industry standard • Slight Learning Curve • Relatively new with future stability unknown

25. Ruby on Rails: Pros • Open Source! • Built for Rapid Application Development • Less development time • Less lines of code • Easy database connectivity • MVC design pattern • Built-in functions • Minimal configuration • Well documented • AJAX made easy

26. Simplicity • Weblog in 15 minutes • http://media.rubyonrails.org/video/rails_take2_with_sound.mov • Ruby search engine • http://ruby.gsmdev.com