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Ruby on Rails 3.1 Release Notes
Highlights in Rails 3.1:
- Streaming
- Reversible Migrations
- Assets Pipeline
- jQuery as the default JavaScript library
These release notes cover only the major changes. To learn about various bug fixes and changes, please refer to the change logs or check out the list of commits in the main Rails repository on GitHub.
Upgrading to Rails 3.1
If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 3 in case you haven't and make sure your application still runs as expected before attempting to update to Rails 3.1. Then take heed of the following changes:
Rails 3.1 requires at least Ruby 1.8.7
Rails 3.1 requires Ruby 1.8.7 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. Rails 3.1 is also compatible with Ruby 1.9.2.
TIP: Note that Ruby 1.8.7 p248 and p249 have marshalling bugs that crash Rails. Ruby Enterprise Edition have these fixed since release 1.8.7-2010.02 though. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults, so if you want to use 1.9.x jump on 1.9.2 for smooth sailing.
What to update in your apps
The following changes are meant for upgrading your application to Rails 3.1.3, the latest 3.1.x version of Rails.
Gemfile
Make the following changes to your Gemfile
.
gem 'rails', '= 3.1.3'
gem 'mysql2'
# Needed for the new asset pipeline
group :assets do
gem 'sass-rails', "~> 3.1.5"
gem 'coffee-rails', "~> 3.1.1"
gem 'uglifier', ">= 1.0.3"
end
# jQuery is the default JavaScript library in Rails 3.1
gem 'jquery-rails'
config/application.rb
-
The asset pipeline requires the following additions:
config.assets.enabled = true config.assets.version = '1.0'
-
If your application is using the "/assets" route for a resource you may want change the prefix used for assets to avoid conflicts:
# Defaults to '/assets' config.assets.prefix = '/asset-files'
config/environments/development.rb
-
Remove the RJS setting
config.action_view.debug_rjs = true
. -
Add the following, if you enable the asset pipeline.
# Do not compress assets config.assets.compress = false # Expands the lines which load the assets config.assets.debug = true
config/environments/production.rb
-
Again, most of the changes below are for the asset pipeline. You can read more about these in the Asset Pipeline guide.
# Compress JavaScripts and CSS config.assets.compress = true # Don't fallback to assets pipeline if a precompiled asset is missed config.assets.compile = false # Generate digests for assets URLs config.assets.digest = true # Defaults to Rails.root.join("public/assets") # config.assets.manifest = YOUR_PATH # Precompile additional assets (application.js, application.css, and all non-JS/CSS are already added) # config.assets.precompile `= %w( admin.js admin.css ) # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies. # config.force_ssl = true
config/environments/test.rb
# Configure static asset server for tests with Cache-Control for performance
config.serve_static_assets = true
config.static_cache_control = "public, max-age=3600"
config/initializers/wrap_parameters.rb
-
Add this file with the following contents, if you wish to wrap parameters into a nested hash. This is on by default in new applications.
# Be sure to restart your server when you modify this file. # This file contains settings for ActionController::ParamsWrapper which # is enabled by default. # Enable parameter wrapping for JSON. You can disable this by setting :format to an empty array. ActiveSupport.on_load(:action_controller) do wrap_parameters :format => [:json] end # Disable root element in JSON by default. ActiveSupport.on_load(:active_record) do self.include_root_in_json = false end
Remove :cache and :concat options in asset helpers references in views
- With the Asset Pipeline the :cache and :concat options aren't used anymore, delete these options from your views.
Creating a Rails 3.1 application
# You should have the 'rails' RubyGem installed
$ rails new myapp
$ cd myapp
Vendoring Gems
Rails now uses a Gemfile
in the application root to determine the gems you require for your application to start. This Gemfile
is processed by the Bundler gem, which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems.
More information: - bundler homepage
Living on the Edge
Bundler
and Gemfile
makes freezing your Rails application easy as pie with the new dedicated bundle
command. If you want to bundle straight from the Git repository, you can pass the --edge
flag:
$ rails new myapp --edge
If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the --dev
flag:
$ ruby /path/to/rails/railties/bin/rails new myapp --dev
Rails Architectural Changes
Assets Pipeline
The major change in Rails 3.1 is the Assets Pipeline. It makes CSS and JavaScript first-class code citizens and enables proper organization, including use in plugins and engines.
The assets pipeline is powered by Sprockets and is covered in the Asset Pipeline guide.
HTTP Streaming
HTTP Streaming is another change that is new in Rails 3.1. This lets the browser download your stylesheets and JavaScript files while the server is still generating the response. This requires Ruby 1.9.2, is opt-in and requires support from the web server as well, but the popular combo of NGINX and Unicorn is ready to take advantage of it.
Default JS library is now jQuery
jQuery is the default JavaScript library that ships with Rails 3.1. But if you use Prototype, it's simple to switch.
$ rails new myapp -j prototype
Identity Map
Active Record has an Identity Map in Rails 3.1. An identity map keeps previously instantiated records and returns the object associated with the record if accessed again. The identity map is created on a per-request basis and is flushed at request completion.
Rails 3.1 comes with the identity map turned off by default.
Railties
-
jQuery is the new default JavaScript library.
-
jQuery and Prototype are no longer vendored and is provided from now on by the
jquery-rails
andprototype-rails
gems. -
The application generator accepts an option
-j
which can be an arbitrary string. If passed "foo", the gem "foo-rails" is added to theGemfile
, and the application JavaScript manifest requires "foo" and "foo_ujs". Currently only "prototype-rails" and "jquery-rails" exist and provide those files via the asset pipeline. -
Generating an application or a plugin runs
bundle install
unless--skip-gemfile
or--skip-bundle
is specified. -
The controller and resource generators will now automatically produce asset stubs (this can be turned off with
--skip-assets
). These stubs will use CoffeeScript and Sass, if those libraries are available. -
Scaffold and app generators use the Ruby 1.9 style hash when running on Ruby 1.9. To generate old style hash,
--old-style-hash
can be passed. -
Scaffold controller generator creates format block for JSON instead of XML.
-
Active Record logging is directed to STDOUT and shown inline in the console.
-
Added
config.force_ssl
configuration which loadsRack::SSL
middleware and force all requests to be under HTTPS protocol. -
Added
rails plugin new
command which generates a Rails plugin with gemspec, tests and a dummy application for testing. -
Added
Rack::Etag
andRack::ConditionalGet
to the default middleware stack. -
Added
Rack::Cache
to the default middleware stack. -
Engines received a major update - You can mount them at any path, enable assets, run generators etc.
Action Pack
Action Controller
-
A warning is given out if the CSRF token authenticity cannot be verified.
-
Specify
force_ssl
in a controller to force the browser to transfer data via HTTPS protocol on that particular controller. To limit to specific actions,:only
or:except
can be used. -
Sensitive query string parameters specified in
config.filter_parameters
will now be filtered out from the request paths in the log. -
URL parameters which return
nil
forto_param
are now removed from the query string. -
Added
ActionController::ParamsWrapper
to wrap parameters into a nested hash, and will be turned on for JSON request in new applications by default. This can be customized inconfig/initializers/wrap_parameters.rb
. -
Added
config.action_controller.include_all_helpers
. By defaulthelper :all
is done inActionController::Base
, which includes all the helpers by default. Settinginclude_all_helpers
tofalse
will result in including only application_helper and the helper corresponding to controller (like foo_helper for foo_controller). -
url_for
and named url helpers now accept:subdomain
and:domain
as options. -
Added
Base.http_basic_authenticate_with
to do simple http basic authentication with a single class method call.class PostsController < ApplicationController USER_NAME, PASSWORD = "dhh", "secret" before_filter :authenticate, :except => [ :index ] def index render :text => "Everyone can see me!" end def edit render :text => "I'm only accessible if you know the password" end private def authenticate authenticate_or_request_with_http_basic do |user_name, password| user_name == USER_NAME && password == PASSWORD end end end
..can now be written as
class PostsController < ApplicationController http_basic_authenticate_with :name => "dhh", :password => "secret", :except => :index def index render :text => "Everyone can see me!" end def edit render :text => "I'm only accessible if you know the password" end end
-
Added streaming support, you can enable it with:
class PostsController < ActionController::Base stream end
You can restrict it to some actions by using
:only
or:except
. Please read the docs atActionController::Streaming
for more information. -
The redirect route method now also accepts a hash of options which will only change the parts of the url in question, or an object which responds to call, allowing for redirects to be reused.
Action Dispatch
-
config.action_dispatch.x_sendfile_header
now defaults tonil
andconfig/environments/production.rb
doesn't set any particular value for it. This allows servers to set it throughX-Sendfile-Type
. -
ActionDispatch::MiddlewareStack
now uses composition over inheritance and is no longer an array. -
Added
ActionDispatch::Request.ignore_accept_header
to ignore accept headers. -
Added
Rack::Cache
to the default stack. -
Moved etag responsibility from
ActionDispatch::Response
to the middleware stack. -
Rely on
Rack::Session
stores API for more compatibility across the Ruby world. This is backwards incompatible sinceRack::Session
expects#get_session
to accept four arguments and requires#destroy_session
instead of simply#destroy
. -
Template lookup now searches further up in the inheritance chain.
Action View
-
Added an
:authenticity_token
option toform_tag
for custom handling or to omit the token by passing:authenticity_token => false
. -
Created
ActionView::Renderer
and specified an API forActionView::Context
. -
In place
SafeBuffer
mutation is prohibited in Rails 3.1. -
Added HTML5
button_tag
helper. -
file_field
automatically adds:multipart => true
to the enclosing form. -
Added a convenience idiom to generate HTML5 data-* attributes in tag helpers from a
:data
hash of options:tag("div", :data => {:name => 'Stephen', :city_state => %w(Chicago IL)}) # => <div data-name="Stephen" data-city-state="["Chicago","IL"]" />
Keys are dasherized. Values are JSON-encoded, except for strings and symbols.
-
csrf_meta_tag
is renamed tocsrf_meta_tags
and aliasescsrf_meta_tag
for backwards compatibility. -
The old template handler API is deprecated and the new API simply requires a template handler to respond to call.
-
rhtml and rxml are finally removed as template handlers.
-
config.action_view.cache_template_loading
is brought back which allows to decide whether templates should be cached or not. -
The submit form helper does not generate an id "object_name_id" anymore.
-
Allows
FormHelper#form_for
to specify the:method
as a direct option instead of through the:html
hash.form_for(@post, remote: true, method: :delete)
instead ofform_for(@post, remote: true, html: { method: :delete })
. -
Provided
JavaScriptHelper#j()
as an alias forJavaScriptHelper#escape_javascript()
. This supersedes theObject#j()
method that the JSON gem adds within templates using the JavaScriptHelper. -
Allows AM/PM format in datetime selectors.
-
auto_link
has been removed from Rails and extracted into the rails_autolink gem
Active Record
-
Added a class method
pluralize_table_names
to singularize/pluralize table names of individual models. Previously this could only be set globally for all models throughActiveRecord::Base.pluralize_table_names
.class User < ActiveRecord::Base self.pluralize_table_names = false end
-
Added block setting of attributes to singular associations. The block will get called after the instance is initialized.
class User < ActiveRecord::Base has_one :account end user.build_account{ |a| a.credit_limit = 100.0 }
-
Added
ActiveRecord::Base.attribute_names
to return a list of attribute names. This will return an empty array if the model is abstract or the table does not exist. -
CSV Fixtures are deprecated and support will be removed in Rails 3.2.0.
-
ActiveRecord#new
,ActiveRecord#create
andActiveRecord#update_attributes
all accept a second hash as an option that allows you to specify which role to consider when assigning attributes. This is built on top of Active Model's new mass assignment capabilities:class Post < ActiveRecord::Base attr_accessible :title attr_accessible :title, :published_at, :as => :admin end Post.new(params[:post], :as => :admin)
-
default_scope
can now take a block, lambda, or any other object which responds to call for lazy evaluation. -
Default scopes are now evaluated at the latest possible moment, to avoid problems where scopes would be created which would implicitly contain the default scope, which would then be impossible to get rid of via Model.unscoped.
-
PostgreSQL adapter only supports PostgreSQL version 8.2 and higher.
-
ConnectionManagement
middleware is changed to clean up the connection pool after the rack body has been flushed. -
Added an
update_column
method on Active Record. This new method updates a given attribute on an object, skipping validations and callbacks. It is recommended to useupdate_attributes
orupdate_attribute
unless you are sure you do not want to execute any callback, including the modification of theupdated_at
column. It should not be called on new records. -
Associations with a
:through
option can now use any association as the through or source association, including other associations which have a:through
option andhas_and_belongs_to_many
associations. -
The configuration for the current database connection is now accessible via
ActiveRecord::Base.connection_config
. -
limits and offsets are removed from COUNT queries unless both are supplied.
People.limit(1).count # => 'SELECT COUNT(*) FROM people' People.offset(1).count # => 'SELECT COUNT(*) FROM people' People.limit(1).offset(1).count # => 'SELECT COUNT(*) FROM people LIMIT 1 OFFSET 1'
-
ActiveRecord::Associations::AssociationProxy
has been split. There is now anAssociation
class (and subclasses) which are responsible for operating on associations, and then a separate, thin wrapper calledCollectionProxy
, which proxies collection associations. This prevents namespace pollution, separates concerns, and will allow further refactorings. -
Singular associations (
has_one
,belongs_to
) no longer have a proxy and simply returns the associated record ornil
. This means that you should not use undocumented methods such asbob.mother.create
- usebob.create_mother
instead. -
Support the
:dependent
option onhas_many :through
associations. For historical and practical reasons,:delete_all
is the default deletion strategy employed byassociation.delete(*records)
, despite the fact that the default strategy is:nullify
for regular has_many. Also, this only works at all if the source reflection is a belongs_to. For other situations, you should directly modify the through association. -
The behavior of
association.destroy
forhas_and_belongs_to_many
andhas_many :through
is changed. From now on, 'destroy' or 'delete' on an association will be taken to mean 'get rid of the link', not (necessarily) 'get rid of the associated records'. -
Previously,
has_and_belongs_to_many.destroy(*records)
would destroy the records themselves. It would not delete any records in the join table. Now, it deletes the records in the join table. -
Previously,
has_many_through.destroy(*records)
would destroy the records themselves, and the records in the join table. [Note: This has not always been the case; previous version of Rails only deleted the records themselves.] Now, it destroys only the records in the join table. -
Note that this change is backwards-incompatible to an extent, but there is unfortunately no way to 'deprecate' it before changing it. The change is being made in order to have consistency as to the meaning of 'destroy' or 'delete' across the different types of associations. If you wish to destroy the records themselves, you can do
records.association.each(&:destroy)
. -
Add
:bulk => true
option tochange_table
to make all the schema changes defined in a block using a single ALTER statement.change_table(:users, :bulk => true) do |t| t.string :company_name t.change :birthdate, :datetime end
-
Removed support for accessing attributes on a
has_and_belongs_to_many
join table.has_many :through
needs to be used. -
Added a
create_association!
method forhas_one
andbelongs_to
associations. -
Migrations are now reversible, meaning that Rails will figure out how to reverse your migrations. To use reversible migrations, just define the
change
method.class MyMigration < ActiveRecord::Migration def change create_table(:horses) do |t| t.column :content, :text t.column :remind_at, :datetime end end end
-
Some things cannot be automatically reversed for you. If you know how to reverse those things, you should define
up
anddown
in your migration. If you define something in change that cannot be reversed, anIrreversibleMigration
exception will be raised when going down. -
Migrations now use instance methods rather than class methods:
class FooMigration < ActiveRecord::Migration def up # Not self.up ... end end
-
Migration files generated from model and constructive migration generators (for example, add_name_to_users) use the reversible migration's
change
method instead of the ordinaryup
anddown
methods. -
Removed support for interpolating string SQL conditions on associations. Instead, a proc should be used.
has_many :things, :conditions => 'foo = #{bar}' # before has_many :things, :conditions => proc { "foo = #{bar}" } # after
Inside the proc,
self
is the object which is the owner of the association, unless you are eager loading the association, in which caseself
is the class which the association is within.You can have any "normal" conditions inside the proc, so the following will work too:
has_many :things, :conditions => proc { ["foo = ?", bar] }
-
Previously
:insert_sql
and:delete_sql
onhas_and_belongs_to_many
association allowed you to call 'record' to get the record being inserted or deleted. This is now passed as an argument to the proc. -
Added
ActiveRecord::Base#has_secure_password
(viaActiveModel::SecurePassword
) to encapsulate dead-simple password usage with BCrypt encryption and salting.# Schema: User(name:string, password_digest:string, password_salt:string) class User < ActiveRecord::Base has_secure_password end
-
When a model is generated
add_index
is added by default forbelongs_to
orreferences
columns. -
Setting the id of a
belongs_to
object will update the reference to the object. -
ActiveRecord::Base#dup
andActiveRecord::Base#clone
semantics have changed to closer match normal Ruby dup and clone semantics. -
Calling
ActiveRecord::Base#clone
will result in a shallow copy of the record, including copying the frozen state. No callbacks will be called. -
Calling
ActiveRecord::Base#dup
will duplicate the record, including calling after initialize hooks. Frozen state will not be copied, and all associations will be cleared. A duped record will returntrue
fornew_record?
, have anil
id field, and is saveable. -
The query cache now works with prepared statements. No changes in the applications are required.
Active Model
-
attr_accessible
accepts an option:as
to specify a role. -
InclusionValidator
,ExclusionValidator
, andFormatValidator
now accepts an option which can be a proc, a lambda, or anything that respond tocall
. This option will be called with the current record as an argument and returns an object which respond toinclude?
forInclusionValidator
andExclusionValidator
, and returns a regular expression object forFormatValidator
. -
Added
ActiveModel::SecurePassword
to encapsulate dead-simple password usage with BCrypt encryption and salting. -
ActiveModel::AttributeMethods
allows attributes to be defined on demand. -
Added support for selectively enabling and disabling observers.
-
Alternate
I18n
namespace lookup is no longer supported.
Active Resource
-
The default format has been changed to JSON for all requests. If you want to continue to use XML you will need to set
self.format = :xml
in the class. For example,class User < ActiveResource::Base self.format = :xml end
Active Support
-
ActiveSupport::Dependencies
now raisesNameError
if it finds an existing constant inload_missing_constant
. -
Added a new reporting method
Kernel#quietly
which silences bothSTDOUT
andSTDERR
. -
Added
String#inquiry
as a convenience method for turning a String into aStringInquirer
object. -
Added
Object#in?
to test if an object is included in another object. -
LocalCache
strategy is now a real middleware class and no longer an anonymous class. -
ActiveSupport::Dependencies::ClassCache
class has been introduced for holding references to reloadable classes. -
ActiveSupport::Dependencies::Reference
has been refactored to take direct advantage of the newClassCache
. -
Backports
Range#cover?
as an alias forRange#include?
in Ruby 1.8. -
Added
weeks_ago
andprev_week
to Date/DateTime/Time. -
Added
before_remove_const
callback toActiveSupport::Dependencies.remove_unloadable_constants!
.
Deprecations:
ActiveSupport::SecureRandom
is deprecated in favor ofSecureRandom
from the Ruby standard library.
Credits
See the full list of contributors to Rails for the many people who spent many hours making Rails, the stable and robust framework it is. Kudos to all of them.
Rails 3.1 Release Notes were compiled by Vijay Dev