Recent notes

is now a subclass of Hash that preserves order (or _is_ a Hash if running Ruby 1.9 or greater)

You might not realize it preserves order because it delegates inspect to its super-class, Hash, which doesn’t preserve order. But you will see that order is preserved if you iterate or use the keys or values methods:

>> names = ['Amy Irving', 'Jane Doe', 'John Doe', 'John Updike', 'Susan Anthony']
>> ordered = names.group_by { |name| name.split.first }
=> #<OrderedHash {"John"=>["John Doe", "John Updike"], "Amy"=>["Amy Irving"], "Susan"=>["Susan Anthony"], "Jane"=>["Jane Doe"]}>

>> ordered.keys
=> ["Amy", "Jane", "John", "Susan"]

>> ordered.each { |first, full| puts first; full.each { |name| puts "  "+name } }
Amy
  Amy Irving
Jane
  Jane Doe
John
  John Doe
  John Updike
Susan
  Susan Anthony

returns an ActiveSupport::OrderedHash

Returns an ActiveSupport::OrderedHash, which is a subclass of Hash that preserves order. If you’re running Ruby 1.9, it is simply an alias for Hash. Surprisingly, you might not realize that OrderedHash is preserving order since it delegates its inspect method to Hash. More at ActiveSupport::OrderedHash.

custom uniq method

Build hash from elements of your Array using attribute as key and the element as value and return values of Hash:

Hash[*ary.map {|obj| [obj.name, obj]}.flatten].values

Interesting usage for polymorphic asset model :)

…to automatically define default scopes of inherited classes.

 class Asset < ActiveRecord::Base

  belongs_to :resource, :polymorphic => true
  before_save :set_asset_type

  def set_asset_type
   self.asset_type = self.class.name
  end

  def self.inherited(subclass)
    super
    subclass.send(:default_scope, :conditions => "asset_type='#{subclass.name}'")
  end
end

W3CDTF Format

Here is the formatted string for the W3CDTF datetime format (http://www.w3.org/TR/NOTE-datetime). It has a semicolon in the timezone part, therefore you cannot use ‘%z’:

Time::DATE_FORMATS[:w3cdtf] = lambda { |time| time.strftime("%Y-%m-%dT%H:%M:%S#{time.formatted_offset}") }

Using html text instead of default response

If you have a string containing html and want to assert_select against it, as the doc states you have to pass in an element (HTML::Node) as the first argument. You can do something like this:

doc = HTML::Document.new('<p><span>example</span></p>')
assert_select doc.root, 'span'

Escape brackets in selector

If you need to escape brackets in a selector, this is the way to do it:

assert_select "input[type=hidden][name='user[role_ids][]']"

Reverse version of camelize

Reverse version of camelize is underscore

Argument Accepted

Accepts a single argument record_separator which is the character or string to chomp.

Why isn’t this shown in the method def at the top?

Argument Accepted

Accepts a single argument sep_string

Undeprecated version

The undeprecated version of this function is here: ActionView::Helpers::PrototypeHelper#link_to_remote

See ActiveResource::Base

http://apidock.com/rails/ActiveResource/Base

Pretty way to test for current environment

You can check your current Rails environment using nice methods such as:

Rails.env.development?
Rails.env.test?
Rails.env.production?
Rails.env.your_custom_environment?

Use this in controllers

Sometimes you’re gonna need this in controllers. Just put this in the controller:

include ActionView::Helpers::NumberHelper

:find takes more keys than written

The documentation says that the :find keywords “may include the :conditions, :joins, :include, :offset, :limit, and :readonly options”. Note that this does not mean that only those options are supported. :sort also works like it should, for example.

Will this method get rid of existing data?

Will this method get rid of existing data?

Default fallback

You can specifly :default option which is useful when the translation is not found. For example:

t(:this_translation_doesnt_exist, :default => 'Ooops!')
# => Ooops!

Or even any number of “fallbacks” - the first not nil is returned:

t(:missing, :default => [:missing_too, :existing, 'Sad panda'])
# => :existing translation

Good introduction to Rails I18n is http://guides.rubyonrails.org/i18n.html

See Column definition

See column

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

Status Codes

Full detail: http://en.wikipedia.org/wiki/List_of_HTTP_status_codes

• 100 - Continue

• 101 - Switching Protocols

• 200 - OK

• 201 - Created

• 202 - Accepted

• 203 - Non-Authoritative Information

• 204 - No Content

• 205 - Reset Content

• 206 - Partial Content

• 300 - Multiple Choices

• 301 - Moved Permanently

• 302 - Found

• 303 - See Other

• 304 - Not Modified

• 305 - Use Proxy

• 306 - No Longer Used

• 307 - Temporary Redirect

• 400 - Bad Request

• 401 - Not Authorised

• 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

• 500 - Internal Server Error

• 501 - Not Implemented

• 502 - Bad Gateway

• 503 - Service Unavailable

• 504 - Gateway Timeout

• 505 - HTTP Version Not Supported

Doesn't return nil if the object you try from isn't nil.

Note that this doesn’t prevent a NoMethodError if you attempt to call a method that doesn’t exist on a valid object.

a = Article.new

a.try(:author) #=> #<Author ...>

nil.try(:doesnt_exist) #=> nil

a.try(:doesnt_exist) #=> NoMethodError: undefined method `doesnt_exist' for #<Article:0x106c7d5d8>

This is on Ruby 1.8.7 patchlevel 174

Alternative:

without using at

[:a, :b, :c].try(:[], 1)

Replacing with "\" and match — a simple solution

A somewhat different approach to the same problem:

v.gsub(/(?=\W)/, '\\') #=> Foo\ Bar\!

But from what you are trying to achieve I suspect you might be interested in Regexp.escape method :)

Attribute names are Strings, not Symbols

Another possible gotcha – the returned hash keys are of type String, not Symbol:

user.attributes["login"] # => "joe"
user.attributes[:login] # => nil

Compare dates

You can check a date resides between two dates.

Date.today.between?(Date.yesterday, Date.tomorrow)

will return true

Date.yesterday.between?(Date.today, Date.tomorrow)

will return false

expire_page outside controller and sweepers

If you want to expire cached pages from scripts or console just use class-method expire_page. But don’t forget about difference between instance and class method. In class-method you pass page url, not a hash of action/controller:

ActionController::Base.expire_page your_page_url

Expire cache from console or whatever...

I know only one possible method:

ApplicationController.new.expire_fragment(:your_fragment)