Ruby on Rails

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Beginner's tutorial
Ruby in 20 minutes

nil?, empty? and blank?

.nil? can be used on any object and is true if the object is nil.

.empty? can be used on strings, arrays and hashes and returns true if:

String length == 0
Array length == 0
Hash length == 0

Running .empty? on something that is nil will throw a NoMethodError.

.blank? will operate on any object
nil.blank? == true
false.blank? == true
[].blank? == true
{}.blank? == true
"".blank? == true
5.blank? == false
"  ".blank? == true
"  ".empty? == false

How to skip active record in rails 3

1. Create new rails project with

rails new myApp --skip-activerecord


In application.rb, remove the require 'rails/all' line and instead add these lines:

require "action_controller/railtie"
require "action_mailer/railtie"
require "active_resource/railtie"
require "rails/test_unit/railtie"
require "sprockets/railtie"

Also see Remove ActiveRecord in Rails 3 and look into the Active Model railscast

Rails 3.2.x:

You'll also need to remove/comment out this line in application.rb

config.active_record.whitelist_attributes = true

And remove/comment these two lines from development.rb

config.active_record.mass_assignment_sanitizer = :strict
config.active_record.auto_explain_threshold_in_seconds = 0.5

Rails 2.x:

In config/environment.rb add (or uncomment) the line

config.frameworks -= [ :active_record, :active_resource, :action_mailer ]

This will cause Rails not to use those frameworks. (Note the nearly-invisible -= !)