gkop/notes.md

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    Rails 4 New Features

Noisebridge Ruby and Rails Class

2013-01-08

Gabe Kopley
gabe@railsschool.org
www.railsschool.org/l/rails-4-new-features

Major New Features


Cache digests


ActionController::Live


Strong parameters


Turbolinks


Creating an Edge Rails App

(tested with 1ce304f8165e4a930f1a8fb1f6706e61f6411096)

$ gem install bundler --pre
$ gem install i18n thor thread_safe
$ git clone git://github.com/rails/rails.git
$ rails/railties/bin/rails new <path> --edge
create  
create  README.rdoc
create  Rakefile
...

$ cd <path>
$ bundle exec rails --version
Rails 4.0.0.beta

(Note you must use bundle exec or binstubs because Rubygems doesn't know about gems bundled from git)

Feature: Cache digests


Cache digests


Automate efficient cache expiration when using nested fragments aka "Russian Doll Caching"


Use with Rails 3.2: https://github.com/rails/cache_digests


Cache digests, continued

Eg. user profile shows his posts and the comments for each post

Profiles, posts, and comments are all fragment cached


Expire comment fragment when comment template is changed


Expire post fragment when the post template or comment template is changed


Expire profile fragment when profile template, post template, or comment template is changed


(demo)


Feature: ActionController::Live


ActionController::Live


Stream data to client with utmost flexibility


Unlike other new features, this one is not packaged for use with Rails 3.2


Detailed post by Tenderlove


(demo)


Feature: Strong parameters


Strong parameters


New mechanism for mass assignment control.


No more attr_accessible in models.  Instead, strong parameters DSL in controllers.


Use with Rails 3.2: https://github.com/rails/strong_parameters


Strong parameters, continued

Background


Rails < 3.2.3 allowed mass assignment of arbitrary attributes by default
@homakov calls attention to security implications of this behavior - rails/rails#5228
Rails committers close @homakov's ticket for various reasons.
@homakov discovers and exploits vulnerability in GitHub caused by Rails' default behavior - https://github.com/rails/rails/commit/b839657
Rails team rushes to ship point release that prohibits mass assignment of attributes by default (Rails 3.2.3)
@wycats proposes Improving Mass Assignment, provokes discussion.
@dhh releases https://github.com/rails/strong_parameters


Strong parameters, continued, continued

More flexible than attr_accessible

(demo)

Strong Parameters screencast by RailsCasts Pro


Feature: Turbolinks


Turbolinks


A little javascript avoids full page reloads when following links, providing more responsive experience to users.


Use with Rails 3.2: https://github.com/rails/turbolinks


Seriously. Numbers. Use them. by Steve Klabnik


(demo)


Other new features


Support for PATCH

Now treats PATCH and PUT requests the same

When updating record, submits forms as "PATCH" requests with _method form parameter

(demo)

Native support for Postgres hstore

http://schneems.com/post/19298469372/you-got-nosql-in-my-postgres-using-hstore-in-rails


Majorly revised Getting Started Guide

http://edgeguides.rubyonrails.org/getting_started.html

No more scaffolding!

New approach: try something, it doesn't work, make it work, repeat...


Dependency on Ruby > 1.9.3

Gems you develop for Rails 4 can assume Ruby >  1.9.3


Lots of changes to ActiveRecord

See links on last slide for details


.all returns relation
#update_columns introduced
Relation#none introduced
Relation#not introduced
Relation#first and Relation#last order by id
Relation#order takes a hash of columns and their orders
Bang methods on relations
Whole bunch of deprecations (eg. many dynamic finders)
Models don't need to subclass ActiveRecord::Base, can mixin instead
...


New form helpers


#collection_checkboxes
#collection_radiobuttons

HTML5-specific


#date_field


WelcomeController

No need to delete public/index.html anymore !


InfoController

http://localhost:3000/rails/info/routes


before_action loads models in scaffolded controllers

Slims down the controller action methods

(demo)

Better exceptions pages


Prettier


Routing errors show routes table


(demo)


Pure-Ruby template handler

app/views/foo/show.json.ruby

Useful for rendering data


Useful links


What's New in Rails 4 screen cast by RailsCasts


Rails 4: What`s New blog post by Steve Schwartz


Rails 4 Whirlwind Tour video presentation by Andy Lindeman


Rails 4.0 Release Notes


Thanks Noisebridge!


If you enjoy the class, please consider making a donation to Noisebridge.