Highlights in Rails 3.2:
Faster Development Mode
New Routing Engine
Automatic Query Explains
Tagged Logging
These release notes cover the major changes, but do not include each bug-fix and changes. If you want to see everything, check out the list of commits in the main Rails repository on GitHub.
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 3.1 in case you haven't and make sure your application still runs as expected before attempting an update to Rails 3.2. Then take heed of the following changes:
Rails 3.2 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 3.2 is also compatible with Ruby 1.9.2.
TIP: Note that Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails. Ruby Enterprise Edition has these fixed since the release of 1.8.7-2010.02. 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 to 1.9.2 or 1.9.3 for smooth sailing.
Update your Gemfile to depend on
rails = 3.2.0
sass-rails ~> 3.2.3
coffee-rails ~> 3.2.1
uglifier >= 1.0.3
rails = 3.2.0
sass-rails ~> 3.2.3
coffee-rails ~> 3.2.1
uglifier >= 1.0.3
Rails 3.2 deprecates vendor/plugins
and Rails 4.0 will remove
them completely. You can start replacing these plugins by extracting them
as gems and adding them in your Gemfile. If you choose not
to make them gems, you can move them into, say,
lib/my_plugin/*
and add an appropriate initializer in
config/initializers/my_plugin.rb
.
There are a couple of new configuration changes you'd want to add in
config/environments/development.rb
:
# Raise exception on mass assignment protection for Active Record models config.active_record.mass_assignment_sanitizer = :strict # Log the query plan for queries taking more than this (works # with SQLite, MySQL, and PostgreSQL) config.active_record.auto_explain_threshold_in_seconds = 0.5
The mass_assignment_sanitizer
config also needs to be added in
config/environments/test.rb
:
# Raise exception on mass assignment protection for Active Record models config.active_record.mass_assignment_sanitizer = :strict
Replace the code beneath the comment in script/rails
with the
following content:
ENGINE_ROOT = File.expand_path('../..', __FILE__) ENGINE_PATH = File.expand_path('../../lib/your_engine_name/engine', __FILE__) require 'rails/all' require 'rails/engine/commands'
# You should have the 'rails' RubyGem installed $ rails new myapp $ cd myapp
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
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 3.2 comes with a development mode that's noticeably faster. Inspired by Active Reload, Rails reloads classes only when files actually change. The performance gains are dramatic on a larger application. Route recognition also got a bunch faster thanks to the new Journey engine.
Rails 3.2 comes with a nice feature that explains queries generated by Arel
by defining an explain
method in
ActiveRecord::Relation
. For example, you can run something
like puts Person.active.limit(5).explain
and the query Arel
produces is explained. This allows to check for the proper indexes and
further optimizations.
Queries that take more than half a second to run are automatically explained in the development mode. This threshold, of course, can be changed.
When running a multi-user, multi-account application, it's a great help to be able to filter the log by who did what. TaggedLogging in Active Support helps in doing exactly that by stamping log lines with subdomains, request ids, and anything else to aid debugging such applications.
From Rails 3.2, the Rails guides are available for the Kindle and free Kindle Reading Apps for the iPad, iPhone, Mac, Android, etc.
Speed up development by only reloading classes if dependencies files
changed. This can be turned off by setting
config.reload_classes_only_on_change
to false.
New applications get a flag
config.active_record.auto_explain_threshold_in_seconds
in the
environments configuration files. With a value of 0.5
in
development.rb
and commented out in
production.rb
. No mention in test.rb
.
Added config.exceptions_app
to set the exceptions application
invoked by the ShowException
middleware when an exception
happens. Defaults to
ActionDispatch::PublicExceptions.new(Rails.public_path)
.
Added a DebugExceptions
middleware which contains features
extracted from ShowExceptions
middleware.
Display mounted engines' routes in rake routes
.
Allow to change the loading order of railties with
config.railties_order
like:
config.railties_order = [Blog::Engine, :main_app, :all]
Scaffold returns 204 No Content for API requests without content. This makes scaffold work with jQuery out of the box.
Update Rails::Rack::Logger
middleware to apply any tags set in
config.log_tags
to ActiveSupport::TaggedLogging
.
This makes it easy to tag log lines with debug information like subdomain
and request id -- both very helpful in debugging multi-user production
applications.
Default options to rails new
can be set in
~/.railsrc
. You can specify extra command-line arguments to be
used every time 'rails new' runs in the .railsrc
configuration file in your home directory.
Add an alias d
for destroy
. This works for
engines too.
Attributes on scaffold and model generators default to string. This allows
the following: rails g scaffold Post title body:text author
Allow scaffold/model/migration generators to accept "index" and "uniq" modifiers. For example,
rails g scaffold Post title:string:index author:uniq price:decimal{7,2}
will create indexes for title
and author
with the
latter being an unique index. Some types such as decimal accept custom
options. In the example, price
will be a decimal column with
precision and scale set to 7 and 2 respectively.
Turn gem has been removed from default Gemfile.
Remove old plugin generator rails generate plugin
in favor of
rails plugin new
command.
Remove old config.paths.app.controller
API in favor of
config.paths["app/controller"]
.
Rails::Plugin
is deprecated and will be removed in Rails 4.0.
Instead of adding plugins to vendor/plugins
use gems or
bundler with path or git dependencies.
Upgraded mail
version to 2.4.0.
Removed the old Action Mailer API which was deprecated since Rails 3.0.
Make ActiveSupport::Benchmarkable
a default module for
ActionController::Base,
so the #benchmark
method
is once again available in the controller context like it used to be.
Added :gzip
option to caches_page
. The default
option can be configured globally using
page_cache_compression
.
Rails will now use your default layout (such as “layouts/application”) when
you specify a layout with :only
and :except
condition, and those conditions fail.
class CarsController layout 'single_car', :only => :show end
Rails will use 'layouts/single_car' when a request comes in :show action, and use 'layouts/application' (or 'layouts/cars', if exists) when a request comes in for any other actions.
form_for is changed to use "#{action}_#{as}" as the css class and id if
:as
option is provided. Earlier versions used
"#{as}_#{action}".
ActionController::ParamsWrapper
on Active Record models now
only wrap attr_accessible
attributes if they were set. If not,
only the attributes returned by the class method
attribute_names
will be wrapped. This fixes the wrapping of
nested attributes by adding them to attr_accessible
.
Log "Filter chain halted as CALLBACKNAME rendered or redirected" every time a before callback halts.
ActionDispatch::ShowExceptions
is refactored. The controller
is responsible for choosing to show exceptions. It's possible to
override show_detailed_exceptions?
in controllers to specify
which requests should provide debugging information on errors.
Responders now return 204 No Content for API requests without a response body (as in the new scaffold).
ActionController::TestCase
cookies is refactored. Assigning
cookies for test cases should now use cookies[]
cookies[:email] = 'user@example.com' get :index assert_equal 'user@example.com', cookies[:email]
To clear the cookies, use clear
.
cookies.clear get :index assert_nil cookies[:email]
We now no longer write out HTTP_COOKIE and the cookie jar is persistent between requests so if you need to manipulate the environment for your test you need to do it before the cookie jar is created.
send_file
now guesses the MIME type from the file extension if
:type
is not provided.
MIME type entries for PDF, ZIP and other formats were added.
Allow fresh_when/stale? to take a record instead of an options hash.
Changed log level of warning for missing CSRF token from
:debug
to :warn
.
Assets should use the request protocol by default or default to relative if no request is available.
Deprecated implied layout lookup in controllers whose parent had a explicit layout set:
class ApplicationController layout "application" end class PostsController < ApplicationController end
In the example above, Posts controller will no longer automatically look up
for a posts layout. If you need this functionality you could either remove
layout "application"
from
ApplicationController
or explicitly set it to nil
in PostsController
.
Deprecated ActionController::UnknownAction
in favour of
AbstractController::ActionNotFound
.
Deprecated ActionController::DoubleRenderError
in favour of
AbstractController::DoubleRenderError
.
Deprecated method_missing
in favour of
action_missing
for missing actions.
Deprecated ActionController#rescue_action
,
ActionController#initialize_template_class
and
ActionController#assign_shortcuts
.
Add config.action_dispatch.default_charset
to configure
default charset for ActionDispatch::Response
.
Added ActionDispatch::RequestId
middleware that'll make a
unique X-Request-Id header available to the response and enables the
ActionDispatch::Request#uuid
method. This makes it easy to
trace requests from end-to-end in the stack and to identify individual
requests in mixed logs like Syslog.
The ShowExceptions
middleware now accepts a exceptions
application that is responsible to render an exception when the application
fails. The application is invoked with a copy of the exception in
env["action_dispatch.exception"]
and with the
PATH_INFO
rewritten to the status code.
Allow rescue responses to be configured through a railtie as in
config.action_dispatch.rescue_responses
.
Deprecated the ability to set a default charset at the controller level,
use the new config.action_dispatch.default_charset
instead.
Add button_tag
support to
ActionView::Helpers::FormBuilder
. This support mimics the
default behavior of submit_tag
.
<%= form_for @post do |f| %> <%= f.button %> <% end %>
Date helpers accept a new option :use_two_digit_numbers =>
true
, that renders select boxes for months and days with a leading
zero without changing the respective values. For example, this is useful
for displaying ISO 8601-style dates such as '2011-08-01'.
You can provide a namespace for your form to ensure uniqueness of id attributes on form elements. The namespace attribute will be prefixed with underscore on the generated HTML id.
<%= form_for(@offer, :namespace => 'namespace') do |f| %> <%= f.label :version, 'Version' %>: <%= f.text_field :version %> <% end %>
Limit the number of options for select_year
to 1000. Pass
:max_years_allowed
option to set your own limit.
content_tag_for
and div_for
can now take a
collection of records. It will also yield the record as the first argument
if you set a receiving argument in your block. So instead of having to do
this:
@items.each do |item| content_tag_for(:li, item) do Title: <%Q item.title %> end end
You can do this:
content_tag_for(:li, @items) do |item| Title: <%Q item.title %> end
Added font_path
helper method that computes the path to a font
asset in public/fonts
.
Passing formats or handlers to render :template and friends like
render :template => "foo.html.erb"
is deprecated.
Instead, you can provide :handlers and :formats directly as options:
render :template => "foo", :formats => [:html, :js],
:handlers => :erb
.
Adds a configuration option config.assets.logger
to control
Sprockets logging. Set it to false
to turn off logging and to
nil
to default to Rails.logger
.
Boolean columns with 'on' and 'ON' values are type cast to true.
When the timestamps
method creates the created_at
and updated_at
columns, it makes them non-nullable by default.
Implemented ActiveRecord::Relation#explain
.
Implements AR::Base.silence_auto_explain
which allows the user
to selectively disable automatic EXPLAINs within a block.
Implements automatic EXPLAIN logging for slow queries. A new configuration
parameter
config.active_record.auto_explain_threshold_in_seconds
determines what's to be considered a slow query. Setting that to nil
disables this feature. Defaults are 0.5 in development mode, and nil in
test and production modes. Rails 3.2 supports this feature in SQLite, MySQL
(mysql2 adapter), and PostgreSQL.
Added ActiveRecord::Base.store
for declaring simple
single-column key/value stores.
class User < ActiveRecord::Base store :settings, accessors: [ :color, :homepage ] end u = User.new(color: 'black', homepage: '37signals.com') u.color # Accessor stored attribute u.settings[:country] = 'Denmark' # Any attribute, even if not specified with an accessor
Added ability to run migrations only for a given scope, which allows to run migrations only from one engine (for example to revert changes from an engine that need to be removed).
rake db:migrate SCOPE=blog
Migrations copied from engines are now scoped with engine's name, for
example 01_create_posts.blog.rb
.
Implemented ActiveRecord::Relation#pluck
method that returns
an array of column values directly from the underlying table. This also
works with serialized attributes.
Client.where(:active => true).pluck(:id) # SELECT id from clients where active = 1
Generated association methods are created within a separate module to allow
overriding and composition. For a class named MyModel, the module is named
MyModel::GeneratedFeatureMethods
. It is included into the
model class immediately after the generated_attributes_methods
module defined in Active Model, so association methods override attribute
methods of the same name.
Add ActiveRecord::Relation#uniq
for generating unique queries.
Client.select('DISTINCT name')
..can be written as:
Client.select(:name).uniq
This also allows you to revert the uniqueness in a relation:
Client.select(:name).uniq.uniq(false)
Support index sort order in SQLite, MySQL and PostgreSQL adapters.
Allow the :class_name
option for associations to take a symbol
in addition to a string. This is to avoid confusing newbies, and to be
consistent with the fact that other options like :foreign_key already allow
a symbol or a string.
has_many :clients, :class_name => :Client # Note that the symbol need to be capitalized
In development mode, db:drop
also drops the test database in
order to be symmetric with db:create
.
Case-insensitive uniqueness validation avoids calling LOWER in MySQL when the column already uses a case-insensitive collation.
Transactional fixtures enlist all active database connections. You can test models on different connections without disabling transactional fixtures.
Add first_or_create
, first_or_create!
,
first_or_initialize
methods to Active Record. This is a better
approach over the old find_or_create_by
dynamic methods
because it's clearer which arguments are used to find the record and
which are used to create it.
User.where(:first_name => "Scarlett").first_or_create!(:last_name => "Johansson")
Added a with_lock
method to Active Record objects, which
starts a transaction, locks the object (pessimistically) and yields to the
block. The method takes one (optional) parameter and passes it to
lock!
.
This makes it possible to write the following:
class Order < ActiveRecord::Base def cancel! transaction do lock! # ... cancelling logic end end end
as:
class Order < ActiveRecord::Base def cancel! with_lock do # ... cancelling logic end end end
Automatic closure of connections in threads is deprecated. For example the following code is deprecated:
Thread.new { Post.find(1) }.join
It should be changed to close the database connection at the end of the thread:
Thread.new { Post.find(1) Post.connection.close }.join
Only people who spawn threads in their application code need to worry about this change.
The set_table_name
, set_inheritance_column
,
set_sequence_name
, set_primary_key
,
set_locking_column
methods are deprecated. Use an assignment
method instead. For example, instead of set_table_name
, use
self.table_name=
.
class Project < ActiveRecord::Base self.table_name = "project" end
Or define your own self.table_name
method:
class Post < ActiveRecord::Base def self.table_name "special_" + super end end Post.table_name # => "special_posts"
Add ActiveModel::Errors#added?
to check if a specific error
has been added.
Add ability to define strict validations with strict =>
true
that always raises exception when fails.
Provide mass_assignment_sanitizer as an easy API to replace the sanitizer behavior. Also support both :logger (default) and :strict sanitizer behavior.
Deprecated define_attr_method
in
ActiveModel::AttributeMethods
because this only existed to
support methods like set_table_name
in Active Record, which
are themselves being deprecated.
Deprecated Model.model_name.partial_path
in favor of
model.to_partial_path
.
Redirect responses: 303 See Other and 307 Temporary Redirect now behave like 301 Moved Permanently and 302 Found.
Added ActiveSupport:TaggedLogging
that can wrap any standard
Logger
class to provide tagging capabilities.
Logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT)) Logger.tagged("BCX") { Logger.info "Stuff" } # Logs "[BCX] Stuff" Logger.tagged("BCX", "Jason") { Logger.info "Stuff" } # Logs "[BCX] [Jason] Stuff" Logger.tagged("BCX") { Logger.tagged("Jason") { Logger.info "Stuff" } } # Logs "[BCX] [Jason] Stuff"
The beginning_of_week
method in Date
,
Time
and DateTime
accepts an optional argument
representing the day in which the week is assumed to start.
ActiveSupport::Notifications.subscribed
provides subscriptions
to events while a block runs.
Defined new methods Module#qualified_const_defined?
,
Module#qualified_const_get
and
Module#qualified_const_set
that are analogous to the
corresponding methods in the standard API, but accept qualified constant
names.
Added #deconstantize
which complements
#demodulize
in inflections. This removes the rightmost segment
in a qualified constant name.
Added safe_constantize
that constantizes a string but returns
nil
instead of raising an exception if the constant (or part
of it) does not exist.
ActiveSupport::OrderedHash
is now marked as extractable when
using Array#extract_options!
.
Added Array#prepend
as an alias for Array#unshift
and Array#append
as an alias for Array#<<
.
The definition of a blank string for Ruby 1.9 has been extended to Unicode whitespace. Also, in Ruby 1.8 the ideographic space U`3000 is considered to be whitespace.
The inflector understands acronyms.
Added Time#all_day
, Time#all_week
,
Time#all_quarter
and Time#all_year
as a way of
generating ranges.
Event.where(:created_at => Time.now.all_week) Event.where(:created_at => Time.now.all_day)
Added instance_accessor: false
as an option to
Class#cattr_accessor
and friends.
ActiveSupport::OrderedHash
now has different behavior for
#each
and #each_pair
when given a block accepting
its parameters with a splat.
Added ActiveSupport::Cache::NullStore
for use in development
and testing.
Removed ActiveSupport::SecureRandom
in favor of
SecureRandom
from the standard library.
ActiveSupport::Base64
is deprecated in favor of
::Base64
.
Deprecated ActiveSupport::Memoizable
in favor of Ruby
memoization pattern.
Module#synchronize
is deprecated with no replacement. Please
use monitor from ruby's standard library.
Deprecated ActiveSupport::MessageEncryptor#encrypt
and
ActiveSupport::MessageEncryptor#decrypt
.
ActiveSupport::BufferedLogger#silence
is deprecated. If you
want to squelch logs for a certain block, change the log level for that
block.
ActiveSupport::BufferedLogger#open_log
is deprecated. This
method should not have been public in the first place.
ActiveSupport::BufferedLogger's
behavior of automatically
creating the directory for your log file is deprecated. Please make sure to
create the directory for your log file before instantiating.
ActiveSupport::BufferedLogger#auto_flushing
is deprecated.
Either set the sync level on the underlying file handle like this. Or tune
your filesystem. The FS cache is now what controls flushing.
f = File.open('foo.log', 'w') f.sync = true ActiveSupport::BufferedLogger.new f
ActiveSupport::BufferedLogger#flush
is deprecated. Set sync on
your filehandle, or tune your filesystem.
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 3.2 Release Notes were compiled by Vijay Dev