Notes posted by mcmire

Moved to ActiveRecord::Persistence

This isn’t deprecated, it was just moved in Rails 3. See:

http://apidock.com/rails/ActiveRecord/Persistence/reload

Moved to ActionDispatch::Routing::PolymorphicRoutes

In Rails 3, this has moved to ActionDispatch::Routing::PolymorphicRoutes.

Re: Caveat when using dynamic layouts

Since there’s no way to edit posts on here, I need to correct myself and say that what I posted before doesn’t work, since you can’t specify layout multiple times:

class OrdersController < BaseController
  layout :determine_layout, :only => :new
  layout "public", :except => :new
  # ...
end

So don’t do that. The only way to ensure that the other actions get the default theme is to drop :only/:except and do the conditions yourself:

class OrdersController < BaseController
  layout :determine_layout

private
  def determine_layout
    %w(new).include?(action_name) ? "some_layout" : "public"
  end
end

All this to say, beware of :only/:except – they aren’t as useful as you think they are.

Caveat when using dynamic layouts

Worth noting that if you have a controller which inherits from another controller which has a layout, and in this child controller you’re determining the layout at runtime using a method for specific actions, the other actions you are excluding will not inherit the layout from the parent controller.

For example, if you’ve got this

class BaseController < ApplicationController
  layout "public"
end
class OrdersController < BaseController
  layout :determine_layout, :only => :new
  # index, show, new, create, edit, update, destroy ...
end

then OrdersController#index, #show, and #edit won’t get the “public” layout – in fact they won’t get a layout at all. So you’ll need to do this instead:

class OrdersController < BaseController
  layout :determine_layout, :only => :new
  layout "public", :except => :new
  # ...
end

Includes all ancestors

May be helpful to know that this returns true if B is any ancestor of A, not just a direct one. As an example:

class Foo; end
class Bar < Foo; end
class Baz < Bar; end

Foo >= Bar #=> true
Foo >= Baz #=> true

Includes all ancestors

May be helpful to know that this returns true if B is any ancestor of A, not just a direct one. As an example:

class Foo; end
class Bar < Foo; end
class Baz < Bar; end

Foo > Bar #=> true
Foo > Baz #=> true

Includes descendants

May be helpful to know that this returns true if A is any descendant of B, not just a direct one. As an example:

class Foo; end
class Bar < Foo; end
class Baz < Bar; end

Bar <= Foo #=> true
Baz <= Foo #=> true

Includes descendants

May be helpful to know that this returns true if A is any descendant of B, not just a direct one. As an example:

class Foo; end
class Bar < Foo; end
class Baz < Bar; end

Bar < Foo #=> true
Baz < Foo #=> true

If you want direct descendance try Class#superclass:

Bar.superclass == Foo #=> true
Baz.superclass == Foo #=> false

Don't forget to require 'tmpdir'

If you simply say Dir.tmpdir you might get a nice surprise:

irb> Dir.tmpdir
NoMethodError: undefined method `tmpdir' for Dir:Class

from (irb):1

Strangely, this method seems to be stored in a file that Ruby doesn’t require by default. Just require 'tmpdir' and all should be well.

irb> require 'tmpdir'
=> true
irb> Dir.tmpdir
=> "/var/folders/An/AnwlXPZFH2aRLCERERQDKE+++TI/-Tmp-"

Overriding default validation messages

Before Rails 2.2 you could globally customize the default validation error messages by changing AR::Base.default_error_messages. The messages have now been moved to i18n, so to customize them in 2.2 and up, just create a locales/ folder in your config/ folder, copy activerecord/lib/active_record/locale/en.yml (in Rails source) to config/locales/en.yml, and then change the strings inside. As szeryf indicated below, the strings of interest are activerecord.errors.messages.

Conditions work for lower-level validate methods too

I don’t think this is mentioned in the docs anywhere, or else I couldn’t find it: Because validate, validate_on_create, and validate_on_update are ActiveSupport::Callbacks, their symbol forms support conditions just like validates_presence_of and company:

validate :permaname_must_be_unique, :if => :normal_entry?
validate_on_create :posted_at_must_be_valid_timestamp, :unless => Proc.new {|e| e.posted_at.nil? }
validate_on_update :title_must_not_contain_apostrophes, :if => :title_starts_with_a_b?

This has moved

See http://apidock.com/rails/ActionView/TemplateHandlers/register_template_handler.

Superclass of OrderedHash

Note that in Rails 2.3, OrderedHash changed from being a subclass of Array to a subclass of Hash. This is contrary to what the documentation says above.

Gotcha with method calls inside select loop

Keep in mind that any methods you call on the object in the select loop will be strung together when the Javascript is rendered. For example:

page.select(".shipping_type_fee").each do |td|
  td.down("span").update("--").show
  td.down("img").hide
end

will be rendered as:

$$('.shipping_type_fee').each(function(value, index) {
  value.down("span").update("--").show().down("img").hide();
});

This is probably not what you want!

Re: Using a Loading Graphic

You probably want to be using :complete, not :loaded, to execute Javascript when an Ajax request has finished. See: http://prototypejs.org/api/ajax/options

List of status codes and their symbols

Note that the :status option accepts not only an HTTP status code (such as 500), but also a symbol representing that code (such as :created), if that makes more sense to you. Here’s a list of which symbols map to which numbers (derived from ActionController::StatusCodes::SYMBOL_TO_STATUS_CODE):

100 = :continue
101 = :switching_protocols
102 = :processing
200 = :ok
201 = :created
202 = :accepted
203 = :non_authoritative_information
204 = :no_content
205 = :reset_content
206 = :partial_content
207 = :multi_status
226 = :im_used
300 = :multiple_choices
301 = :moved_permanently
302 = :found
303 = :see_other
304 = :not_modified
305 = :use_proxy
307 = :temporary_redirect
400 = :bad_request
401 = :unauthorized
402 = :payment_required
403 = :forbidden
404 = :not_found
405 = :method_not_allowed
406 = :not_acceptable
407 = :proxy_authentication_required
408 = :request_timeout
409 = :conflict
410 = :gone
411 = :length_required
412 = :precondition_failed
413 = :request_entity_too_large
414 = :request_uri_too_long
415 = :unsupported_media_type
416 = :requested_range_not_satisfiable
417 = :expectation_failed
422 = :unprocessable_entity
423 = :locked
424 = :failed_dependency
426 = :upgrade_required
500 = :internal_server_error
501 = :not_implemented
502 = :bad_gateway
503 = :service_unavailable
504 = :gateway_timeout
505 = :http_version_not_supported
507 = :insufficient_storage
510 = :not_extended