Recent notes

March 13, 2010

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Can be used with has_many associations

You can also use this to validate that a has_many association has a specified number of records on the other end:

  has_many :members

  validates_length_of :members, :minimum => 1

March 12, 2010

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Skips validations and callbacks

The method skips validations and callbacks. That is why it should be used with caution.

Code example

  person.toggle :active

March 11, 2010

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Use message param

The message param is invaluable in case test fails — if you use it to display relevant info, you will find out what went wrong much faster.

Reworking the silly example above:

  assert some_list.include?(5)

will only tell you that

  <false> is not true.

which isn’t terribly helpful, is it? But if you use message like that:

  assert some_list.include?(5), "some_list = #{some_list.inspect}"

the output will be:

  some_list = [1, 2].
  <false> is not true.

which in most cases should give you strong hints as to why the test failed.

March 11, 2010

0 thanks

Good way to see what went wrong

Use the message parameter like that:

  assert_response :success, @response.body

If this fails (the response isn’t a success), it will display the response body along with the failure message, thus allowing you to quickly find out what went wrong. If the response is e.g. 500, there will probably be some exception stacktrace displayed in the body. And so on.

March 10, 2010

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Specify your own template

You can specify you own template this way:

  def notice
    ...
    @template = "some_other_name.html.erb"
  end

March 8, 2010

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Eagerness

Check out this simple example:

 "Hello Ruby friend".sub(/^(.*)e/,  'X')  # => "Xnd"
 "Hello Ruby friend".sub(/^(.*?)e/, 'X')  # => "Xllo Ruby friend"

The question mark turns the dotstar into non-eager mode which means it will halt on the first subsequent "e" rather than the last one. This comes in handy e.g. for Cucumber step definitions.

Okay, but not really nice:

 /^I am using rvm "([^\"]*)" with gemset "(.*)"$/

Much more readable and consistent equivalent to the above:

 /^I am using rvm "(.*?)" with gemset "(.*?)"$/

March 4, 2010

0 thanks

AASM named scopes

If you are using the aasm plugin/gem, this will generate all named scopes for your various states.

Code example

  Class Article <  ActiveRecord::Base

    include AASM

    aasm_initial_state :created

    aasm_state :published
    aasm_state :unpublished
    aasm_state :deleted
    aasm_state :created

    aasm_event :publish do
      transitions :to => :published, :from => [:created]
    end

    aasm_event :unpublish do
      transitions :to => :unpublished, :from => [:created, :published]
    end

    aasm_event :delete do
      transitions :to => :deleted, :from => [:published, :unpublished]
    end

    aasm_states.each { |s| named_scope s, :conditions => { :state => s.to_s } }

  end

March 4, 2010 - (>= 1.2.8)

0 thanks

stub_chain is very useful when testing controller code

or any other chained method call type that you’d like to stub, example:

in your controller:

   def new
     @user = current_site.users.new
   end

in your spec:

   it "#new should assign a @user" do
     u = mock("User")
     controller.stub_chain(:current_site, :users, :new).and_return(u)
     assigns[:user].should == u
   end

whereas before you had to stub each chained method call separately:

   it "#new should assign a @user" do
     u = mock("User")
     users = mock("Users collection", :new => u)
     site = mock("Site", :users => users)
     controller.stub!(:current_site).and_return(site)
     assigns[:user].should == u
   end

Please note that stub_chain was added to RSpec in version 1.2.6

March 4, 2010

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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.

March 3, 2010

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Deprecated in 1.9.x!

Use FileUtils::copy instead. It is also in 1.8.x, FileUtils, so call that one instead.

March 3, 2010 - (>= v1_8_6_287)

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makedirs(path) to create file path

mkdir will only create a single directory on an existing path. If you want to create a full path, like the `mkdir -p /full/path` command, use the makedirs method.

1.8: File.makedirs(path) 1.9: FileUtils.makedirs(path)

February 27, 2010

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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

February 26, 2010

0 thanks

default_scope on create

If you specify :conditions in your default_scope in form of a Hash, they will also be applied as default values for newly created objects. Example:

  class Article
    default_scope :conditions => {:published => true}
  end

  Article.new.published? # => true

However:

  class Article
    default_scope :conditions => 'published = 1'
  end

  Article.new.published? # => false

February 25, 2010 - (>= v2.3.4)

0 thanks

configuration no longer in environment.rb

configure session store in config/initializers/session_store.rb

February 25, 2010

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Saving other objects inside before_save

Don’t call .save or .update_attribute on other objects inside before_save callback.

Saving other objects inside of before_save callback results in flushing changed hash and the original object is not updated.

UPDATE observed sometimes, still investigating

February 25, 2010

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Redirect...

See ActiveRecord::ConnectionAdapters::TableDefinition#column for details of the options you can use.

February 25, 2010

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Possible gotcha

This method returns a Pathname object which handles paths starting with a / as absolute (starting from the root of the filesystem). Compare:

  >> Rails.root
  => #<Pathname:/some/path/to/project>
  >> Rails.root + "file"
  => #<Pathname:/some/path/to/project/file>
  >> Rails.root + "/file"
  => #<Pathname:/file>
  >> Rails.root.join "file"
  => #<Pathname:/some/path/to/project/file>
  >> Rails.root.join "/file"
  => #<Pathname:/file>

February 25, 2010

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See documentation for the class method

Since Rails version 2, this instance method no longer exists.

You may be looking for its namesake class method, ActiveRecord::Base.method_missing

February 23, 2010

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Easy workaround for missing :through option

Note that belongs_to does not support :through option like has_many (although IMHO it would make sense in some cases), but you can easily simulate it with delegate.

For example:

  class Person < ActiveRecord::Base
    belongs_to :team
    ...
  end

  class Task < ActiveRecord::Base
    belongs_to :person
    delegate :team, :to => :person
  end

There is of course more ways to do it, but this seems to be the easiest to me.

February 23, 2010

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note: the example format regex is too lenient

The example regex for RFC 2822 email is too lenient. Sure it’s just an example, but it wound up in our code and we just had to fix it to match the RFC.

The regex as given allows any non-@ non-whitespace characters. But the RFC only allows these characters in mailbox names

  alpha digit - ! \ # $ % & ' * + \ / = ? ^ _ ` { | } ~ ] +

and . is only allowed between atoms of 1 or more of the above.

Here’s the corrected regex:

  :with => /\A([-a-z0-9!\#$%&'*+\/=?^_`{|}~]+\.)*[-a-z0-9!\#$%&'*+\/=?^_`{|}~]+@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i

February 19, 2010

1 thank

Hash#except

Note that the ActiveSupport library provides the except and except! methods, which return the Hash minus the given keys. So you don’t need to write your own wrapper if you happen to be using Rails or ActiveSupport as a stand-alone library:

http://apidock.com/rails/ActiveSupport/CoreExtensions/Hash/Except/except

February 16, 2010

0 thanks

Re: POST DATA

The ampersand is more common, but the W3C recommends that all web servers support semicolon separators in the place of ampersand separators:

http://www.w3.org/TR/1999/REC-html401-19991224/appendix/notes.html#h-B.2.2

February 16, 2010 - (>= v2.1.0)

0 thanks

Extract the aggregated scoping options

If you want to get the aggregated scoping options of a chain of named scopes use ActiveRecord::Base.current_scoped_methods

It works in the fashion of:

  Shirt.red.medium.alphabetical.current_scoped_methods
  # ==>
  {
    :create => {},
    :find => {
      :conditions => {:color => 'red', :size => 'medium'},
      :order => 'shirts.name ASC'
    }
  }

February 12, 2010

0 thanks

Example

Delete all files in log

  require 'FileUtils'
  FileUtils.rm_rf(Dir.glob("log/*"))

February 12, 2010

1 thank

Check content_for content

There is a content_for? method in Rails wherewith you can check the content. http://github.com/rails/rails/commit/9cb8c812f2a23ab5653a7888740a014a02c97c18#diff-1

But it’s not in the last stable version (2.3.5) http://github.com/rails/rails/blob/v2.3.5/actionpack/lib/action_view/helpers/capture_helper.rb

February 12, 2010

0 thanks

re: Options

@ramanavel - The options are dependent on the cache store that you’re using. You’ll need to have a look at what the cache store you’re using allows.

e.g. MemCacheStore allows the use of time criteria based :expires_in, most of the cache stores don’t.

http://guides.rubyonrails.org/caching_with_rails.html might provide a little more information.

February 11, 2010 - (v1_8_6_287 - v1_8_7_72)

0 thanks

Using Unshift with Load Path's

Using unshift on your load path’s for Rails, Sinatra, etc, is a good way of ensuring that the file your including is going to be first.

Example

  vendor = File.join(File.dirname(__FILE__), 'vendor')
  $LOAD_PATH.unshift File.expand_path(File.join(vendor, 'ultraviolet-0.10.5',  'lib'))

Can be used with has_many associations

Complete Formatting Codes

Complete Formatting Codes

Skips validations and callbacks

Code example

Use message param

Available statuses

Good way to see what went wrong

Specify your own template

Eagerness

AASM named scopes

Code example

stub_chain is very useful when testing controller code

Re: Caveat when using dynamic layouts

Deprecated in 1.9.x!

makedirs(path) to create file path

Caveat when using dynamic layouts

default_scope on create

configuration no longer in environment.rb

Saving other objects inside before_save

Redirect...

Possible gotcha

See documentation for the class method

Easy workaround for missing :through option

note: the example format regex is too lenient

Hash#except

Re: POST DATA

Extract the aggregated scoping options

Example

Delete all files in log

Check content_for content

re: Options

Using Unshift with Load Path's

Example