What's new in Rails 2?

What’s new in Rails 2?

Bryan Helmkamp

http://brynary.com /

“Look at all the things I’m NOT doing.”

–DHH during the “Creating a blog

in 15 minutes” screencast

Evolutionary, not revolutionary.

ActiveRecord

Numerical validation

Gains the ability to specify comparisons.

Examples:

validates_numericality_of :salary , :greater_than => 49_000

validates_numericality_of :age , :less_than_or_equal => 99

validates_numericality_of :employees , :greater_than => 0

:allow_blank => true

Skips validation for empty strings and nil.

XML in, JSON out

>> Post.new .from_xml ({:title => "Hello!", :body => "text"}.to_xml)

=> #<Post id: nil, title: "Hello!", body: "text", created_at: nil, updated_at: nil>

>> Post.new(:title => "Hello!", :body => "text") .to_json

=> "{"updated_at": null, "title": "Hello!", "body": "text", "created_at": null}"

Sexy migrations

create_table :posts do | t |

t.belongs_to :blog , :null => false

t.string :title , :subtitle

t.text :body

t.timestamps

end

Query cache

Very dumb. Checks SQL string equality.

Cleared by any INSERT/UPDATE/DELETE.

Enabled per-action by default.

Can be skipped if necessary:

def self.uncached_newest

uncached do

find( :all , :order => :created_at )

end

end

Foxy Fixtures

Three main features

Don’t specify the IDs for each record.

Reference associated fixtures by name.

Sets created_at and updated_at to Time.now automatically.

Foxy Fixtures example

# blogs.yml

my_blog:

name: "My awesome blog"

# posts.yml

first_post:

blog: my_blog

title: "First post!"

fixtures :all

Load all fixtures for all test cases. (Recommended!)

ActionPack

Cookie sessions

Now the default session store.

Stored in clear text, secured with a hash.

Configure a secret in environment.rb:

Rails :: Initializer .run do | config |

config.action_controller.session = {

:session_key => '_rails_app_session',

:secret => 'e96a9......aef9111a'

}

end

HTTP-only cookies

Prevents access to cookies from JavaScript.

CSRF protection

Enabled by default in application.rb

Uses a token to verify requests are from the application, not a malicious site.

Built-in to form_tag and friends.

Partial layouts

Use with partials:

<% render :partial => "post", :layout => "window" %>

or with a block:

<% render :layout => "window", :locals => { :name => "Recent" } do %>

<% for post in @recent_posts %>

<h2> <%=h post.title %> </h2>

<% end %>

<% end %>

Route namespaces

map.namespace :admin do | admin |

# Maps to Admin::PostsController

admin.resources :posts

end

# Maps to PostsController

map.resources :posts

Semicolon is dead. Long live forward slash! Long live forward slash!

Association routing shortcuts

map.resources :blogs , :has_many => [ :posts , :themes ],

:has_one => :owner

HTTP authentication

class PostsController < ApplicationController

USER_NAME , PASSWORD = "bryan", "secret"

before_filter :authenticate , :except => [ :index ]

...

private

def authenticate

authenticate_or_request_with_http_basic do | user_name , password |

user_name == USER_NAME && password == PASSWORD

end

end

end

Exception handlers

class ApplicationController < ActionController::Base

rescue_from User :: NotAuthorized , :with => :deny_access

rescue_from 'MyAppError::Base' do | exception |

render :xml => exception.to_xml, :status => 500

end

protected

def deny_access

# ...

end

end

Asset caching

Concatenates file contents.

Only active in production mode.

Examples:

<%= stylesheet_link_tag "reset", "main", :cache => true %>

<%# Cache in public/javascripts/special.js %>

<%= javascript_include_tag "whiz", "bang", :cache => "special" %>

Asset servers

Distributes request to four asset hosts.

Speeds up page load time considerably.

In production.rb:

ActionController :: Base .asset_host = "asset%d.example.com"

AtomFeedHelper

# index.atom.builder:

atom_feed do | feed |

feed.title("Bryan's Bytes")

feed.updated(( @posts .first.created_at))

for post in @posts

feed.entry(post) do | entry |

entry.title(post.title)

entry.content(post.body, :type => 'html')

entry.author do | author |

author.name("NYC.rb")

end

end

end

end

Multiview

Template filename changes:

filename .format.renderer

Examples:

show.csv.erb

edit.html.haml

index.atom.builder

simply_helpful

Now in core... but you should’ve been using it already.

dom_class and dom_id

dom_class(@person) => "person"

dom_class(Person) => "person"

dom_class(@person, :edit) => "edit_person"

dom_id(@person) => "person_1234"

dom_id(Person.new) => "new_person"

div_for/content_tag_for

<% div_for @person do %>

<% end %>

<div class="person" id="person_42">

</div>

url_for for models

url_for(@post) works like post_path(@post).

url_for(Post.new) works like new_post_path.

Works with link_to, redirect_to, etc.

render :partial for AR

render :partial => @post works like render :partial => "post", :object => @post

render :partial => @posts works like render :partial => "post", :collection => @posts

form_for

Determines form action based on the record. (e.g. post_path or new_post_path)

New records use :method => :post

Existing records use :method => :put

Automatically adds a HTML class and ID

form_for example

<% form_for @person do | f | %>

<%= f.text_field :name %>

<% end %>

<form action="/people" method="post" class="person" id="new_person">

<input type="text" name="person[name]" id="person_name" />

</form>

Extra Goodies

Debugging

Getting started

sudo gem install -y ruby-debug

Call the method “debugger” in your code

script/server --debugger

Debugger commands

irb – Drop into an irb session

list – List the code surround the breakpoint

p/pp – Print results of an expression

up – Move one frame higher

cont – Resume execution

next/step – Execute one line at a time.

where – Display the current stack

Live demo

assert_emails

# Assert one email is sent during action

assert_emails 1 do

post :signup , :name => "Bryan"

end

# Assert no emails are sent

post :signup , :name => ""

assert_no_emails

Hash filtering

Hash#except is the inverse of Hash#slice.

Example:

>> {:foo => 1, :bar => 2}.except(:bar, :baz)

=> {:foo=>1}

Database Rake tasks

rake db:create and db:create:all

rake db:drop and db:drop:all

rake db:reset

rake db:rollback (defaults to STEP=1)

rake db:version

List routes with Rake

$ rake routes

posts GET /posts {:controller=>"posts", :action=>"index"}

formatted_posts GET /posts.:format {:controller=>"posts", :action=>"index"}

POST /posts {:controller=>"posts", :action=>"create"}

POST /posts.:format {:controller=>"posts", :action=>"create"}

new_post GET /posts/new {:controller=>"posts", :action=>"new"}

formatted_new_post GET /posts/new.:format {:controller=>"posts", :action=>"new"}

edit_post GET /posts/:id/edit {:controller=>"posts", :action=>"edit"}

formatted_edit_post GET /posts/:id/edit.:format {:controller=>"posts", :action=>"edit"}

post GET /posts/:id {:controller=>"posts", :action=>"show"}

formatted_post GET /posts/:id.:format {:controller=>"posts", :action=>"show"}

PUT /posts/:id {:controller=>"posts", :action=>"update"}

PUT /posts/:id.:format {:controller=>"posts", :action=>"update"}

DELETE /posts/:id {:controller=>"posts", :action=>"destroy"}

DELETE /posts/:id.:format {:controller=>"posts", :action=>"destroy"}

/:controller/:action/:id

/:controller/:action/:id.:format

Initializer hooks

Rails load order:

config/preinitializer.rb

config/environment.rb

config/environments/RAILS_ENV.rb

config/initializers/*.rb

Code annotations

Finds FIXME, TODO and OPTIMIZE comments.

$ rake notes

app/models/post.rb:

* [ 2] [TODO] : Add support for themes

app/views/layouts/application.rhtml:

* [ 1] [FIXME] Will break with less than three posts

Request profiler

sudo gem install -y ruby-prof

Example:

$ cat login_session.rb

get_with_redirect '/'

post_with_redirect '/sessions', :password => 'NYC.rb!'

$ ./script/performance/request -n 10 login_session.rb

Losing weight

ActionWebService is out. Use ActiveResource for REST. Use ActiveResource for REST.

acts_as_* behaviors

script/plugin install http://svn.rubyonrails.org/rails/plugins/acts_as_list/

script/plugin install http://svn.rubyonrails.org/rails/plugins/acts_as_nested_set/

script/plugin install http://svn.rubyonrails.org/rails/plugins/acts_as_tree/

Controller variables

Don’t use @params, @session, @flash, @request or @env.

Just drop the “@” and use the methods.

ActiveRecord finders

Post.find_all becomes Post.find(:all).

Post.find_first becomes Post.find(:first).

Components

Interesting feature, but too slow .

Try refactoring to partials and filters...

...or grab Sebastian Delmont’s plugin:

http://dev.notso.net/svn/rails/plugins/embedded_actions/trunk/

Renamed routes

Nested resources now use the parent name as a prefix.

Example:

map.resources :blogs do | blog |

blog.resources :posts

end

post_path becomes blog_ post_path, etc.

Pagination

Switch to will_paginate (recommended).

http://errtheblog.com/posts/56-im-paginating-again

Or install the classic_pagination plugin:

script/plugin install svn://errtheblog.com/svn/plugins/classic_pagination

Database adapters

Adapters except SQLite, MySQL and PostgreSQL were removed from Rails core.

sudo gem install activerecord- oracle -adapter

Form helpers

start_form_tag and end_form_tag are gone.

Switch to the form_tag block syntax.

Use form_for when possible.

form_tag example

<%= start_form_tag posts_path %>

<%= text_field :post , :title %>

<%= end_form_tag %>

becomes

<% form_tag posts_path do %>

<%= text_field :post , :title %>

<% end %>

AJAX view helpers

Autocomplete and in-place editing moved to plugins.

script/plugin install http://svn.rubyonrails.org/rails/plugins/auto_complete/

script/plugin install http://svn.rubyonrails.org/rails/plugins/in_place_editing/

“Use the Source, Luke.”

How to upgrade

Upgrade to Rails 1.2.6.

Eliminate deprecation warnings.

Make sure all your tests pass.

Upgrade to Rails 2.0.1.

Run Mislav’s Rails 2 compatibility checker script. ( http://pastie.caboo.se/private/krcevozww61drdeza13e3a )

Make sure all your tests pass.

Questions? What’s new in Rails 2? Bryan Helmkamp http://brynary.com / / / /

http://www.flickr.com/photos/kaufman/81616562/

http://icanhascheezburger.com/2007/01/12/wait-ill-fix-it/

Photos used

What's new in Rails 2?

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