Advanced Active Record Techniques: Best Practice Refactoring

Advanced Active Record Techniques: Best Practice Refactoring

<br />#p54<br /><br />class ArticleVersion < ActiveRecord::Base<br /> before_validation_on_create :set_version_number<br /> <br /> before_create :mark_related_links_not_current, :if => :current_version<br /><br /> private<br /> <br /> def current_version<br /> article.current_version<br /> end<br /> <br /> #下面兩個method 都會call 到 article.current_version <br /> #這樣就可以抽出來<br /> #然後mark_related_linkers_not_current 會需要判斷 article.current_version 的存在與否這也可以利用 Conditional Callback 來判斷<br /><br /> def set_version_number<br /> self.version = (current_version ? current_version.version : 0) + 1<br /> end<br /><br /> def mark_related_links_not_current<br /> current_version.relateds.each do |rel|<br /> rel.update_attribute(:current, false)<br /> end<br /> end<br />end<br /><br />#================================================================<br />#p74<br />class ArticleVersion < ActiveRecord::Base<br /> STATES = { :edit => 'Edit',<br /> :edit_check => 'Edit Check',<br /> :sub_edit => 'Sub Edit',<br /> :publish_ready => 'Publish Ready',<br /> :published => 'Published' }<br /><br /> STATES.each do |key, value|<br /> define_method "#{key}?", {<br /> self.state == "#{value}"<br /> }<br /> end<br />end<br /><br /><br />#=========================================================<br /># p84<br /><br />class Role < ActiveRecord::Base<br /> has_and_belongs_to_many :users<br /> validates_presence_of :name<br /> validates_uniqueness_of :name<br /><br /> def name=(value)<br /> write_attribute("name", value.downcase)<br /> end<br /><br /> # 想用symbol 拿值<br /> def self.[](name) # Get a role quickly by using: Role[:admin]<br /> self.find(:first, :conditions => ["name = ?", name.id2name])<br /> end<br /><br /> def add_user(user)<br /> self.users << user<br /> end<br /><br /> def delete_user(user)<br /> self.users.delete(user)<br /> end<br />end<br /><br /><br />#====================================================<br /># p91<br /><br />class User < ActiveRecord::Base<br /> has_many :roles<br />end<br /><br />class Role < ActiveRecord::Base<br /> TYPES = %w(admin editor writer guest)<br /> validates_inclusion_of :name, :in => TYPES<br /><br /> # 生成 class method<br /> class << self<br /> TYPES.each do |role_type|<br /> define_method "#{role_type}?" do<br /> # Exists? http://api.rubyonrails.org/classes/ActiveRecord/Base.html#M002268<br /> roles.exists?(:name => role_type)<br /> end<br /> end<br /> end<br />end<br /><br /><br /># =====================================================<br /># p96<br /><br /># Step 1<br />class User < ActiveRecord::Base<br /> include Addressable<br />end<br /><br />class Order < ActiveRecord::Base<br /> include Addressable<br />end<br /><br />module Addressable<br /> def self.included(base)<br /> base.validates_presence_of :billing_address_one, :billing_city, :billing_state,<br /> :billing_zip, :billing_country<br /> base.validates_presence_of :shipping_address_one, :shipping_city, :shipping_state,<br /> :shipping_zip, :shipping_country<br /> base.validates_format_of :billing_zip,<br /> :with => /\d{5}(-\d{4})?/,<br /> :if => Proc.new { |klass| klass.billing_country == "US" }<br /> base.validates_format_of :shipping_zip,<br /> :with => /\d{5}(-\d{4})?/,<br /> :if => Proc.new { |klass| klass.shipping_country == "US" }<br /> base.validates_format_of :billing_zip,<br /> :with => /[a-zA-Z]\d[a-zA-Z] \d[a-zA-Z]\d/,<br /> :if => Proc.new { |klass| klass.billing_country == "CA" }<br /> base.validates_format_of :shipping_zip,<br /> :with => /[a-zA-Z]\d[a-zA-Z] \d[a-zA-Z]\d/,<br /> :if => Proc.new { |klass| klass.shipping_country == "CA" }<br /> end<br />end<br /><br /><br /><br /># Step 2<br /><br />class User < ActiveRecord::Base<br /> has_address :shipping<br /> has_address :billing<br /> has_many :orders<br />end<br /><br />module Addressable<br /> class << self<br /> def included(base)<br /> base.extend ClassMethods<br /> end<br /> end<br /><br /> module ClassMethods<br /> def has_address(name = "")<br /> name = "#{name}_" unless name.blank?<br /> validates_presence_of "#{name}address_one", "#{name}city",<br /> "#{name}state_province", "#{name}postal_code", "#{name}country"<br /> validates_format_of "#{name}postal_code", :with => /\d{5}(-\d{4})?/,<br /> :if => Proc.new { |user| user["#{name}country"] == "US" }<br /> validates_format_of "#{name}postal_code", :with => /[a-zA-Z]\d[a-zA-Z] \d[a-zA-Z]\d/,<br /> :if => Proc.new { |user| user["#{name}country"] == "CA" }<br /> end<br /> end<br />end<br /><br />ActiveRecord::Base.send :include, Addressable<br /><br /><br /><br /># Step 3<br /><br /> <br />class User < ActiveRecord::Base<br /> has_address :shipping<br /> has_address :billing<br /> <br /> has_many :orders<br />end<br /><br />module Addressable<br /> class << self<br /> def included(base)<br /> base.extend ClassMethods<br /> end<br /> end<br /><br /> module ClassMethods<br /> def has_address(name)<br /> name << “_” unless name.blank?<br /> validates_presence_of "#{name}address_one", "#{name}city",<br /> "#{name}state_province", "#{name}postal_code", "#{name}country"<br /> validates_format_of "#{name}postal_code", :with => /\d{5}(-\d{4})?/,<br /> :if => Proc.new { |user| user["#{name}country"] == "US" }<br /> validates_format_of "#{name}postal_code", :with => /[a-zA-Z]\d[a-zA-Z] \d[a-zA-Z]\d/,<br /> :if => Proc.new { |user| user["#{name}country"] == "CA" }<br /> composed_of "#{name}address", :class_name => “Address”,<br /> :mapping => [ ["#{name}address_one", "address_one"],<br /> ["#{name}address_two", "address_two"],<br /> ["#{name}city", "city"],<br /> ["#{name}state_province", "state_province"],<br /> ["#{name}postal_code", "postal_code"]<br /> ["#{name}country", "country"] ]<br /> end<br /> end<br />end<br /><br />ActiveRecord::Base.send :include, Addressable<br /><br />