Get started with Rails 3

Rails 3: Overview

RVM: Ruby Version Manager

Basic Rails 3 App

by Karmen Blake

Rails 3: Overview

Rails 3: Overview

MerbFastLightweightPowerful = featureful, flexible, and extensible

RailsPopularEasy to get startedOpinionatedLarge ecosystem: books, blogs, screencasts, community

Rails 3: Overview

Ruby Version Manager (RVM)

Why?

For me, I've been attached to Ruby 1.8.6 for a long time. Mostly because it is stable and legacy projects I work on rely on it. Lots of gems installed that just work.Rails 3 requires 1.8.7 and above! Doh!!!

Ruby Version Manager (RVM)

Command line tool which allows us to easily install, manage and work with multiple ruby environments (and associated gems).

Ruby Version Manager (RVM)

Ruby Version Manager (RVM)

Installation:

> mkdir -p ~/.rvm/src/ && cd ~/.rvm/src && rm -rf ./rvm/ && git clone --depth 1 git://github.com/wayneeseguin/rvm.git && cd rvm && ./install

That is a long command, eh.

You might want to go here and read for yourself: http://rvm.beginrescueend.com/rvm/install/

Follow instructions after that which involves adding a line to your bash profile.

Installing Rails Using RVM

> rvm install 1.9.1 (or 1.8.7 or 1.9.2)

> rvm 1.9.1 --default (uses 1.9.1 on newly opened terminal windows)

> curl -L http://rvm.beginrescueend.com/gemsets/rails3.gems -o rails3.gems

> rvm gemset import rails3.gems> rails -v (should show Rails 3 beta)

You may have to install sqlite/mysql and associated gems. For example,

> gem install sqlite3-ruby

Ruby Version Manager (RVM)

A few more things:

To use system ruby installed by default:> rvm system --default

See installed rubies:> rvm list

Named Gem SetsRVM not only isolates different ruby installations it also lets you isolate different gem sets. Thus you can mix and match rubies and gem sets. Amazing!! More here: http://rvm.beginrescueend.com/gemsets/basics/

Introduction to Rails 3

Generate a Rails 3 app> rails generate app_name> rails g app_name

script/rails is the only thing in there!

Generate scaffold> rails g scaffold Post title:string body:text > rake db:migrate

Start server> rails server> rails s

Introduction to Rails 3

Console> rails console> rails c

Database Console> rails dbconsole> rails db

Introduction to Rails 3

ActiveRecord Validation

Rails 2 - separate validations validates_presence_of :titlevalidates_uniqueness_of :titlevalidates_length_of :title, :maximum => 35

Rails 3 - puts validations together for a fieldvalidates :title, :presence => true, :uniqueness => true, :length => {:maximum => 35}

Introduction to Rails 3

ActiveRecord Query Interface

New APIwhere(:conditions)having(:conditions)selectgrouporderlimitincludes(:include)and more...

Introduction to Rails 3

ActiveRecord Query Interface

Why New API?

Chainability!!!! No not gold chains. :)

Post.where(:title => "test")Post.where(:title => "test").order("created_at DESC")Post.order("created_at").limit(10)Post.where("created_at <= ?", Time.now).includes(:comments)

Introduction to Rails 3

ActiveRecord Query Interface

Lazy Loading

posts = Post.all

Returns a ActiveRelation object containing information about query.

As soon as you access ActiveRelation object, for example in view, then call gets executed to db. Nice for fragment caching, etc.

<% posts.each do |post| %> <li><%= post.title %></li><% end %>

Introduction to Rails 3

More Rails 3 Goodies:

Router

Mailer

Unobtrusive Javascript

...

Will have to wait for another presentation. :)

Introduction to Rails 3

All you want to know and more about Rails 3

http://mediumexposure.com/rails-3-reading-material/ http://www.rubyinside.com/rails-3-0-beta-links-2966.html http://railslove.com/weblog/2010/02/02/on-the-way-to-rails-3-a-link-list/http://railsnotes.com/rails-3/

References

http://www.slideshare.net/GreggPollack/rails-3-beautiful-code-3219240http://guides.rails.info/getting_started.htmlhttp://railscasts.com/episodes/202-active-record-queries-in-rails-3http://m.onkey.org/2010/1/22/active-record-query-interfacehttp://rvm.beginrescueend.com/pik

rvm tool on windows, I've never used thoughhttp://github.com/vertiginous/pik

Karmen Blake

http://www.dudeblake.comhttp://blog.dudeblake.comhttp://twitter.com/kblakehttp://github.com/kblake