module-izing has_one :page association

git-svn-id: http://svn.barleysodas.com/barleysodas/trunk@37 0f7b21a7-9e3a-4941-bbeb-ce5c7c368fa7

app/models/beer.rb

@@ -3,10 +3,7 @@
 #
 class Beer < ActiveRecord::Base
   belongs_to :brewery
-  has_one :page, :foreign_key => 'owner_id', :dependent => :destroy,
-    :conditions => "pages.owner_type = 'Beer'"
-  before_save :ensure_page_valid
-  after_save :save_page
+  has_one_tuxwiki_page :owner_class => 'Beer'
   
   ##
   # Returns a list of attributes for the Page partial.
@@ -25,32 +22,4 @@ class Beer < ActiveRecord::Base
     end
     pattr
   end
-  
-  protected
-  
-  ##
-  # This model always has a Page associated. Save it before this model to make
-  # sure that everything is kosher with the name and whatnot.
-  #
-  def save_page
-    page.save
-  end
-  
-  ##
-  # This will let the Page model keep track of names being unique and all.
-  # Might be nil, so let the after_save hook create it.
-  #
-  def ensure_page_valid
-    if page.nil?
-      self.errors.add(:page, "is missing")
-    else
-      page.owner = self
-      page.title = self.title
-      page.errors.each do |key, val|
-        self.errors.add(key, val)
-      end if !page.valid?
-    end
-    return false if self.errors.size > 0
-    true
-  end
 end

app/models/brewery.rb

@@ -3,10 +3,7 @@
 #
 class Brewery < ActiveRecord::Base
   has_many :beers
-  has_one :page, :foreign_key => 'owner_id', :dependent => :destroy,
-    :conditions => "pages.owner_type = 'Brewery'"
-  before_save :ensure_page_valid
-  after_save :save_page
+  has_one_tuxwiki_page :owner_class => 'Brewery'
   
   ##
   # Returns a list of attributes to add into the Page display.
@@ -16,32 +13,4 @@ class Brewery < ActiveRecord::Base
     pattr << "Available Beers: #{beers.size}"
     pattr
   end
-  
-  protected
-  
-  ##
-  # This model always has a Page associated. Save it before this model to make
-  # sure that everything is kosher with the name and whatnot.
-  #
-  def save_page
-    page.save
-  end
-  
-  ##
-  # This will let the Page model keep track of names being unique and all.
-  # Might be nil, so let the after_save hook create it.
-  #
-  def ensure_page_valid
-    if page.nil?
-      self.errors.add(:page, "is missing")
-    else
-      page.owner = self
-      page.title = self.title
-      page.errors.each do |key, val|
-        self.errors.add(key, val)
-      end if !page.valid?
-    end
-    return false if self.errors.size > 0
-    true
-  end
 end

config/environment.rb

@@ -9,3 +9,4 @@ end
 
 require 'redcloth'
 require 'actionview_text_helper'
+require 'has_one_page'

lib/has_one_page.rb

@@ -0,0 +1,68 @@
+module ActiveRecord # :nodoc:
+  class Base # :nodoc:
+    class << self
+      ##
+      # This method will add a has_one :page association and a few useful
+      # callbacks to the requested model. It expects to have a
+      # :owner_class parameter given so that it knows what the owner class
+      # name should be. The associated model will automatically be deleted
+      # when this model is deleted.
+      #
+      # The Page will automatically have the title updated from the owner's
+      # title field and be saved after a successful save. When a Page errors
+      # on validation, the errors are automatically copied into the owner so
+      # that the user doesn't even have to know what is going on.
+      #
+      def has_one_tuxwiki_page(options = {})
+        return if self.included_modules.include?(TuxWiki::HasOnePage)
+        send :include, TuxWiki::HasOnePage
+        
+        # we need a class name for right now. i don't know how to inflect it
+        # on my own, yet.
+        options[:owner_class] ||= 'Page'
+        
+        class_eval do
+          has_one :page, :foreign_key => 'owner_id', :dependent => :destroy,
+            :conditions => "pages.owner_type = '#{options[:owner_class]}'"
+          before_save :ensure_tuxwiki_page_valid
+          after_save :save_tuxwiki_page
+        end
+      end
+    end
+  end
+end
+
+module TuxWiki # :nodoc:
+  module HasOnePage # :nodoc:
+    
+    protected
+    
+    ##
+    # This model always has a Page associated. Save it before this
+    # model to make sure that everything is kosher with the name and
+    # whatnot.
+    #
+    def save_tuxwiki_page
+      self.page.save
+    end
+    
+    ##
+    # This will let the Page model keep track of names being unique and
+    # all. Might be nil, so let the after_save hook create it. Also
+    # copies the errors from the page model into the owner model.
+    #
+    def ensure_tuxwiki_page_valid
+      if self.page.nil?
+        self.errors.add(:page, "is missing")
+      else
+        self.page.owner = self
+        self.page.title = self.title
+        self.page.errors.each do |key, val|
+          self.errors.add(key, val)
+        end if !self.page.valid?
+      end
+      return false if self.errors.size > 0
+      true
+    end
+  end
+end