Adding validator for hex colors that adheres to HTML 5 simple-color s…

…pec.

app/models/layer.rb

@@ -1,2 +1,5 @@
 class Layer < ActiveRecord::Base
+
+ # Validations
+ validates :color, :hex_color => true
 end

lib/hex_color_validator.rb

@@ -0,0 +1,13 @@
+# Validates a hexidecimal color string as defined in the HTML 5 spec.
+# This validator only works for the simple case and does not support
+# any legacy formats. See http://dev.w3.org/html5/spec/Overview.html#valid-simple-color
+# for the format spec.
+class HexColorValidator < ActiveModel::EachValidator
+  # Verifies a color string is 7 characters long and contains
+  # only hex values after the pound sign.
+  def validate_each(object, attribute, value)  
+    unless value =~ /^#[0-9a-fA-F]{6}$/ 
+      object.errors[attribute] << (options[:message] || " is not a properly formatted color string")  
+    end  
+  end  
+end