Allow symbol as values for `tokenize` of `LengthValidator`

4 files changed, 32 insertions, 7 deletions

diff --git a/activemodel/CHANGELOG.md b/activemodel/CHANGELOG.md
index 8d22e3ac46..aa1f3debb5 100644
--- a/activemodel/CHANGELOG.md
+++ b/activemodel/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Allow symbol as values for `tokenize` of `LengthValidator`
+
+    *Kensuke Naito*
+
 *   Validate options passed to `ActiveModel::Validations.validate`.
 
     Preventing, in many cases, the simple mistake of using `validate` instead of `validates`.
diff --git a/activemodel/lib/active_model/validations/length.rb b/activemodel/lib/active_model/validations/length.rb
index a96b30cadd..c63a9d74b3 100644
--- a/activemodel/lib/active_model/validations/length.rb
+++ b/activemodel/lib/active_model/validations/length.rb
@@ -38,7 +38,7 @@ module ActiveModel
       end
 
       def validate_each(record, attribute, value)
-        value = tokenize(value)
+        value = tokenize(record, value)
         value_length = value.respond_to?(:length) ? value.length : value.to_s.length
         errors_options = options.except(*RESERVED_OPTIONS)
 
@@ -59,10 +59,14 @@ module ActiveModel
       end
 
       private
-
-      def tokenize(value)
-        if options[:tokenizer] && value.kind_of?(String)
-          options[:tokenizer].call(value)
+      def tokenize(record, value)
+        tokenizer = options[:tokenizer]
+        if tokenizer && value.kind_of?(String)
+          if tokenizer.kind_of?(Proc)
+            tokenizer.call(value)
+          elsif record.respond_to?(tokenizer)
+            record.send(tokenizer, value)
+          end
         end || value
       end
 
@@ -108,8 +112,8 @@ module ActiveModel
       # * <tt>:message</tt> - The error message to use for a <tt>:minimum</tt>,
       #   <tt>:maximum</tt>, or <tt>:is</tt> violation. An alias of the appropriate
       #   <tt>too_long</tt>/<tt>too_short</tt>/<tt>wrong_length</tt> message.
-      # * <tt>:tokenizer</tt> - Specifies how to split up the attribute string.
-      #   (e.g. <tt>tokenizer: ->(str) { str.scan(/\w+/) }</tt> to count words
+      # * <tt>:tokenizer</tt> - Specifies a method, proc or string to how to split up the attribute string.
+      #   (e.g. <tt>tokenizer: ->(str) { str.scan(/\w+/) }</tt> or <tt>tokenizer: :word_tokenizer</tt> to count words
       #   as in above example). Defaults to <tt>->(value) { value.split(//) }</tt>
       #   which counts individual characters.
       #
diff --git a/activemodel/test/cases/validations/length_validation_test.rb b/activemodel/test/cases/validations/length_validation_test.rb
index 046ffcb16f..3fa9f9274c 100644
--- a/activemodel/test/cases/validations/length_validation_test.rb
+++ b/activemodel/test/cases/validations/length_validation_test.rb
@@ -331,6 +331,19 @@ class LengthValidationTest < ActiveModel::TestCase
     assert_equal ["Your essay must be at least 5 words."], t.errors[:content]
   end
 
+
+  def test_validates_length_of_with_symbol
+    Topic.validates_length_of :content, minimum: 5, too_short: "Your essay must be at least %{count} words.",
+                                        tokenizer: :my_word_tokenizer
+    t = Topic.new(content: "this content should be long enough")
+    assert t.valid?
+
+    t.content = "not long enough"
+    assert t.invalid?
+    assert t.errors[:content].any?
+    assert_equal ["Your essay must be at least 5 words."], t.errors[:content]
+  end
+
   def test_validates_length_of_for_fixnum
     Topic.validates_length_of(:approved, is: 4)
 
diff --git a/activemodel/test/models/topic.rb b/activemodel/test/models/topic.rb
index 1411a093e9..fed50bc361 100644
--- a/activemodel/test/models/topic.rb
+++ b/activemodel/test/models/topic.rb
@@ -37,4 +37,8 @@ class Topic
     errors.add attr, "is missing" unless send(attr)
   end
 
+  def my_word_tokenizer(str)
+   str.scan(/\w+/)
+  end
+
 end