Rails 2.0 - Preview Release

Its time to feel the Real Power of Rails.
The Rails 2.0 preview version is just released.

I've listed down some of the important updates of Rails 2.0 here

Action Pack - Multiview

In Rails 2.0, the format of the template is separated from its rendering engine. So show.rhtml now becomes show.html.erb, which is the template that’ll be rendered by default for a show action that has declared format.html in its respond_to. And you can now have something like show.csv.erb, which targets text/csv, but also uses the default ERB renderer.

So the new format for templates is action.format.renderer. A few examples:

• show.erb: same show template for all formats
• index.atom.builder: uses the Builder format, previously known as rxml, to render an index action for the application/atom+xml mime type

Action Pack: Record identification

Piggy-backing off the new drive for resources are a number of simplifications for controller and view methods that deal with URLs. We’ve added a number of conventions for turning model classes into resource routes on the fly. Examples:

# person is a Person object, which by convention will
# be mapped to person_url for lookup
redirect_to(person)
link_to(person.name, person)
form_for(person)

Action Pack: HTTP Loving

New module is added in Rails 2.0 to work with HTTP Basic Authentication, which turns out to be a great way to do API authentication over SSL. It’s terribly simple to use. Here’s an example (there are more in ActionController::HttpAuthentication):

class PostsController < password = "dhh" 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

Active Record: Sexy migrations

There’s a new alternative format for declaring migrations in a slightly more efficient format. Before you’d write:

create_table :people do |t|
t.column, "account_id",  :integer
t.column, "first_name",  :string, :null => false
t.column, "last_name",   :string, :null => false
t.column, "description", :text
t.column, "created_at",  :datetime
t.column, "updated_at",  :datetime
end

Now you can write:

create_table :people do |t|
t.integer :account_id
t.string  :first_name, :last_name, :null => false
t.text    :description
t.timestamps
end

And hundreds upon hundreds of other improvements

We’ve got literally hundreds of bug fixes, tweaks, and feature enhancements crammed into Rails 2.0. All this coming off the work of tons of eager contributors working tirelessly to improve the framework in small, but important ways.

So how do I upgrade?

If you want to move your application to Rails 2.0, you should first move it to Rails 1.2.3. That’ll include deprecation warnings for most everything we yanked out in 2.0. So if your application runs fine on 1.2.3 with no deprecation warnings, there’s a good chance that it’ll run straight up on 2.0. Of course, if you’re using, say, pagination, you’ll need to install the classic_pagination plugin. If you’re using Oracle, you’ll need to install the activerecord-oracle-adapter gem. And so on and so forth for all the extractions.

To install the preview release through gems, do:

gem install rails --source http://gems.rubyonrails.org

To try it from an SVN tag, use:

rake rails:freeze:edge TAG=rel_2-0-0_PR


Thanks to David Heinemeier Hansson and the core team of committers and hundreds of open-source contributors