Allow validations to use values from custom readers [#2936 state:resolved]

Signed-off-by: Joshua Peek <josh@joshpeek.com>

5 files changed, 71 insertions, 4 deletions

diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index a4cf700231..a47d89ac0e 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -68,7 +68,7 @@ module ActiveModel
     # Will add an error message to each of the attributes in +attributes+ that is empty.
     def add_on_empty(attributes, custom_message = nil)
       [attributes].flatten.each do |attribute|
-        value = @base.send(attribute)
+        value = @base.instance_eval { read_attribute_for_validation(attribute) }
         is_empty = value.respond_to?(:empty?) ? value.empty? : false
         add(attribute, :empty, :default => custom_message) unless !value.nil? && !is_empty
       end
@@ -77,7 +77,7 @@ module ActiveModel
     # Will add an error message to each of the attributes in +attributes+ that is blank (using Object#blank?).
     def add_on_blank(attributes, custom_message = nil)
       [attributes].flatten.each do |attribute|
-        value = @base.send(attribute)
+        value = @base.instance_eval { read_attribute_for_validation(attribute) }
         add(attribute, :blank, :default => custom_message) if value.blank?
       end
     end
@@ -146,7 +146,7 @@ module ActiveModel
       defaults = defaults.compact.flatten << :"messages.#{message}"
 
       key = defaults.shift
-      value = @base.send(attribute)
+      value = @base.instance_eval { read_attribute_for_validation(attribute) }
 
       options = { :default => defaults,
         :model => @base.class.name.humanize,
diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
index 54a869396d..0fca96e5cc 100644
--- a/activemodel/lib/active_model/validations.rb
+++ b/activemodel/lib/active_model/validations.rb
@@ -66,7 +66,7 @@ module ActiveModel
         # Declare the validation.
         send(validation_method(options[:on]), options) do |record|
           attrs.each do |attr|
-            value = record.send(attr)
+            value = record.instance_eval { read_attribute_for_validation(attr) }
             next if (value.nil? && options[:allow_nil]) || (value.blank? && options[:allow_blank])
             yield record, attr, value
           end
@@ -95,6 +95,28 @@ module ActiveModel
     def invalid?
       !valid?
     end
+    
+    protected
+      # Hook method defining how an attribute value should be retieved. By default this is assumed
+      # to be an instance named after the attribute. Override this method in subclasses should you
+      # need to retrieve the value for a given attribute differently e.g.
+      #   class MyClass
+      #     include ActiveModel::Validations
+      #
+      #     def initialize(data = {})
+      #       @data = data
+      #     end
+      #     
+      #     private
+      #     
+      #     def read_attribute_for_validation(key)
+      #       @data[key]
+      #     end
+      #   end
+      #
+      def read_attribute_for_validation(key)
+        send(key)
+      end
   end
 end
 
diff --git a/activemodel/test/cases/validations/presence_validation_test.rb b/activemodel/test/cases/validations/presence_validation_test.rb
index aa5bdf1e62..bb6fb91774 100644
--- a/activemodel/test/cases/validations/presence_validation_test.rb
+++ b/activemodel/test/cases/validations/presence_validation_test.rb
@@ -54,4 +54,18 @@ class PresenceValidationTest < ActiveModel::TestCase
       assert p.valid?
     end
   end
+  
+  def test_validates_presence_of_for_ruby_class_with_custom_reader
+    repair_validations(Person) do
+      CustomReader.validates_presence_of :karma
+
+      p = CustomReader.new
+      assert p.invalid?
+
+      assert_equal ["can't be blank"], p.errors[:karma]
+
+      p[:karma] = "Cold"
+      assert p.valid?
+    end
+  end
 end
diff --git a/activemodel/test/cases/validations_test.rb b/activemodel/test/cases/validations_test.rb
index 8c89494247..0b340e68bf 100644
--- a/activemodel/test/cases/validations_test.rb
+++ b/activemodel/test/cases/validations_test.rb
@@ -5,6 +5,7 @@ require 'cases/tests_database'
 require 'models/topic'
 require 'models/reply'
 require 'models/developer'
+require 'models/custom_reader'
 
 class ValidationsTest < ActiveModel::TestCase
   include ActiveModel::TestsDatabase
@@ -97,6 +98,19 @@ class ValidationsTest < ActiveModel::TestCase
     assert_equal %w(gotcha gotcha), t.errors[:title]
     assert_equal %w(gotcha gotcha), t.errors[:content]
   end
+  
+  def test_validates_each_custom_reader
+    hits = 0
+    CustomReader.validates_each(:title, :content, [:title, :content]) do |record, attr|
+      record.errors.add attr, 'gotcha'
+      hits += 1
+    end
+    t = CustomReader.new("title" => "valid", "content" => "whatever")
+    assert !t.valid?
+    assert_equal 4, hits
+    assert_equal %w(gotcha gotcha), t.errors[:title]
+    assert_equal %w(gotcha gotcha), t.errors[:content]
+  end
 
   def test_validate_block
     Topic.validate { |topic| topic.errors.add("title", "will never be valid") }
diff --git a/activemodel/test/models/custom_reader.rb b/activemodel/test/models/custom_reader.rb
new file mode 100644
index 0000000000..7ac70e6167
--- /dev/null
+++ b/activemodel/test/models/custom_reader.rb
@@ -0,0 +1,17 @@
+class CustomReader
+  include ActiveModel::Validations
+
+  def initialize(data = {})
+    @data = data
+  end
+  
+  def []=(key, value)
+    @data[key] = value
+  end
+
+  private
+  
+  def read_attribute_for_validation(key)
+    @data[key]
+  end
+end
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