r4854@ks: jeremy | 2006-07-30 00:59:18 -0700

Attribute methods
 r4877@ks:  jeremy | 2006-07-30 20:23:53 -0700
 Factor the attribute#{suffix} methods out of method_missing for easier extension.
 r4878@ks:  jeremy | 2006-07-30 20:42:23 -0700
 More specific method naming, declare many attribute method suffixes, set up default suffixes at module include rather than lazily.


git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4632 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Factor the attribute#{suffix} methods out of method_missing for easier extension. [Jeremy Kemper]
+
 * Patch sql injection vulnerability when using integer or float columns. [Jamis Buck]
 
 * Allow #count through a has_many association to accept :include.  [Dan Peterson]

activerecord/lib/active_record.rb

@@ -52,6 +52,7 @@ require 'active_record/migration'
 require 'active_record/schema'
 require 'active_record/calculations'
 require 'active_record/xml_serialization'
+require 'active_record/attribute_methods'
 
 ActiveRecord::Base.class_eval do
   include ActiveRecord::Validations
@@ -69,6 +70,7 @@ ActiveRecord::Base.class_eval do
   include ActiveRecord::Acts::NestedSet
   include ActiveRecord::Calculations
   include ActiveRecord::XmlSerialization
+  include ActiveRecord::AttributeMethods
 end
 
 unless defined?(RAILS_CONNECTION_ADAPTERS)

activerecord/lib/active_record/attribute_methods.rb

@@ -0,0 +1,75 @@
+module ActiveRecord
+  module AttributeMethods #:nodoc:
+    DEFAULT_SUFFIXES = %w(= ? _before_type_cast)
+
+    def self.included(base)
+      base.extend ClassMethods
+      base.attribute_method_suffix *DEFAULT_SUFFIXES
+    end
+
+    # Declare and check for suffixed attribute methods.
+    module ClassMethods
+      # Declare a method available for all attributes with the given suffix.
+      # Uses method_missing and respond_to? to rewrite the method
+      #   #{attr}#{suffix}(*args, &block)
+      # to
+      #   attribute#{suffix}(#{attr}, *args, &block)
+      #
+      # An attribute#{suffix} instance method must exist and accept at least
+      # the attr argument.
+      #
+      # For example:
+      #   class Person < ActiveRecord::Base
+      #     attribute_method_suffix '_changed?'
+      #
+      #     private
+      #       def attribute_changed?(attr)
+      #         ...
+      #       end
+      #   end
+      #
+      #   person = Person.find(1)
+      #   person.name_changed?    # => false
+      #   person.name = 'Hubert'
+      #   person.name_changed?    # => true
+      def attribute_method_suffix(*suffixes)
+        attribute_method_suffixes.concat suffixes
+        rebuild_attribute_method_regexp
+      end
+
+      # Returns MatchData if method_name is an attribute method.
+      def match_attribute_method?(method_name)
+        rebuild_attribute_method_regexp unless defined?(@@attribute_method_regexp) && @@attribute_method_regexp
+        @@attribute_method_regexp.match(method_name)
+      end
+
+      private
+        # Suffixes a, ?, c become regexp /(a|\?|c)$/
+        def rebuild_attribute_method_regexp
+          suffixes = attribute_method_suffixes.map { |s| Regexp.escape(s) }
+          @@attribute_method_regexp = /(#{suffixes.join('|')})$/.freeze
+        end
+
+        # Default to =, ?, _before_type_cast
+        def attribute_method_suffixes
+          @@attribute_method_suffixes ||= []
+        end
+    end
+
+    private
+      # Handle *? for method_missing.
+      def attribute?(attribute_name)
+        query_attribute(attribute_name)
+      end
+
+      # Handle *= for method_missing.
+      def attribute=(attribute_name, value)
+        write_attribute(attribute_name, value)
+      end
+
+      # Handle *_before_type_cast for method_missing.
+      def attribute_before_type_cast(attribute_name)
+        read_attribute_before_type_cast(attribute_name)
+      end
+  end
+end

activerecord/lib/active_record/base.rb

@@ -1671,13 +1671,13 @@ module ActiveRecord #:nodoc:
       # person.respond_to?("name?") which will all return true.
       def respond_to?(method, include_priv = false)
         if @attributes.nil?
-          return super 
+          return super
         elsif attr_name = self.class.column_methods_hash[method.to_sym]
           return true if @attributes.include?(attr_name) || attr_name == self.class.primary_key
           return false if self.class.read_methods.include?(attr_name)
         elsif @attributes.include?(method_name = method.to_s)
           return true
-        elsif md = /(=|\?|_before_type_cast)$/.match(method_name)
+        elsif md = self.class.match_attribute_method?(method.to_s)
           return true if @attributes.include?(md.pre_match)
         end
         # super must be called at the end of the method, because the inherited respond_to?
@@ -1750,6 +1750,7 @@ module ActiveRecord #:nodoc:
         end
       end
 
+
       # Allows access to the object attributes, which are held in the @attributes hash, as were
       # they first-class methods. So a Person class with a name attribute can use Person#name and
       # Person#name= and never directly use the attributes hash -- except for multiple assigns with
@@ -1767,15 +1768,10 @@ module ActiveRecord #:nodoc:
           md ? query_attribute(method_name) : read_attribute(method_name)
         elsif self.class.primary_key.to_s == method_name
           id
-        elsif md = /(=|_before_type_cast)$/.match(method_name)
+        elsif md = self.class.match_attribute_method?(method_name)
           attribute_name, method_type = md.pre_match, md.to_s
           if @attributes.include?(attribute_name)
-            case method_type
-              when '='
-                write_attribute(attribute_name, args.first)
-              when '_before_type_cast'
-                read_attribute_before_type_cast(attribute_name)
-            end
+            __send__("attribute#{method_type}", attribute_name, *args, &block)
           else
             super
           end

activerecord/test/attribute_methods_test.rb

@@ -0,0 +1,30 @@
+require 'abstract_unit'
+
+class AttributeMethodsTest < Test::Unit::TestCase
+  def setup
+    @target = Class.new(ActiveRecord::Base)
+    @target.table_name = 'topics'
+  end
+
+  def test_match_attribute_method_query_returns_match_data
+    assert_not_nil md = @target.match_attribute_method?('title=')
+    assert_equal 'title', md.pre_match
+    assert_equal ['='], md.captures
+  end
+
+  def test_declared_attribute_method_affects_respond_to_and_method_missing
+    topic = @target.new(:title => 'Budget')
+    assert topic.respond_to?('title')
+    assert_equal 'Budget', topic.title
+    assert !topic.respond_to?('title_hello_world')
+    assert_raise(NoMethodError) { topic.title_hello_world }
+
+    @target.class_eval "def attribute_hello_world(*args) args end"
+    @target.attribute_method_suffix '_hello_world'
+
+    assert topic.respond_to?('title_hello_world')
+    assert_equal ['title'], topic.title_hello_world
+    assert_equal ['title', 'a'], topic.title_hello_world('a')
+    assert_equal ['title', 1, 2, 3], topic.title_hello_world(1, 2, 3)
+  end
+end