Monday, October 12, 2009

What's New in Edge Rails

Posted by Nathaniel Bibler

So, Edge Rails is still chugging right along. There are new and interesting fixes, changes, and refactors going on all of the time. So, lets take a look at just a few that’ve gone in since the last post (it’s been a while, I know, I’m sorry!).

ActionView and Helpers

XSS escaping is now enabled by default. This means that if you want to explicitly output HTML to your views, you’ll probably have to mark it as html_safe! before sending it through.

<%= 'my <a href="http://www.rubyonrails.org">safe</a> string'.html_safe! %>

Many of the built-in helpers have been updated for this change and if you see an issues with the Rails helpers being incorrectly sanitized, you should create a new ticket.

distance_of_time_in_words has gained ‘over’, ‘about’, and ‘almost’ keywords, thanks to Jay Pignata and John Trupiano. This provides you with an improved level of granularity when approximating the amount time passed. So, instead of just “2 years ago”, it can now also report “almost 2 years ago,” “about 2 years ago,” and “over 2 years ago,” depending on the proximity to being exactly 2 years old.

assert_equal "almost 2 years",  distance_of_time_in_words(from, to + 2.years - 3.months + 1.day)
assert_equal "about 2 years",   distance_of_time_in_words(from, to + 2.years + 3.months - 1.day)
assert_equal "over 2 years",    distance_of_time_in_words(from, to + 2.years + 3.months + 1.day)
assert_equal "over 2 years",    distance_of_time_in_words(from, to + 2.years + 9.months - 1.day)
assert_equal "almost 3 years",  distance_of_time_in_words(from, to + 2.years + 9.months + 1.day)

The HTML form helper, fields_for - generally used for nesting additional model forms - now allows for explicit collections to be used, thanks to Andrew France. So, instead of just including all of your blog.posts, you should have it only display your published blog.posts, for example. Or:

<% form_for @person, :url => { :action => "update" } do |person_form| %>
  ...
  <% person_form.fields_for :projects, @active_projects do |project_fields| %>
    Name: <%= project_fields.text_field :name %>
  <% end %>
<% end %>

API Change for content_tag_for: The third argument - being the optional CSS prefix - will now also affect the generated CSS class. This prefix will now be appended to the generated element’s CLASS attribute.

<%= content_tag_for(:li, @post, :published) %>
# => <li id="published_post_123" class="published_post">...</li>

ActiveResource and ActiveRecord

Taryn East has added update_attribute(s) methods to ActiveResource. These methods act very similarly to the ActiveRecord methods we already know and love.

Building or creating an object through a has_one association that contains conditionals will now automatically append those conditions to the newly created object, thanks to Luciano Panaro.

class Blog
  has_author :commit_author, :class_name => 'Author', :conditions => {:name => "Luciano Panaro"}
end

@blog.build_commit_author
# => #<Author name: "Luciano Panaro" ... >

Pratik Naik added a new option to ActiveRecord’s accepts_nested_attributes_for to :limit the number of records that are allowed to be processed. Also, while we’re covering accepts_nested_attributes_for, José Valim as renamed the _delete option to _destroy to better follow what is actually occurring. A deprecation warning has been added to _delete, for the time being.

Jacob Burkhart updated the new autosave option in Rails 2.3 to allow for an :autosave => false, which will disallow saving of associated objects, even when they are new_record?s.

Some Internals

Previously, CDATA elements could be ignored when converting from XML to a Hash, so now, thanks to John Pignata, Hash#from_xml will now properly parse and include CDATA elements values.

Josh Peek has relocated global exception handling into ActionDispatch::Rescue. So, this is now being handled at the Rack middleware level.

And finally, Yehuda Katz and Carl Lerche began work on a Rails::Application object to better encapsulate some of the application start up and configuration details. Also, a good bit of initialization has now gone on to move into this new object.

Remember, if you prefer to have a shorter audio summary of some of this content and more, you should check out the Ruby5 podcast over at Envy Labs; it’s released every Tuesday and Friday with the latest news in the Ruby and Rails community.

Photo: Clock Tower by Brian Taylor