ActiveModel::MassAssignmentSecurity.mass_assignment_sanitizer method

In order to specify your own sanitize method
Implemented .mass_assignment_sanitizer configuration option

activemodel/lib/active_model/mass_assignment_security.rb

@@ -11,7 +11,13 @@ module MassAssignmentSecurity
       class_attribute :_accessible_attributes
       class_attribute :_protected_attributes
       class_attribute :_active_authorizer
-      class_attribute :mass_assignment_sanitizer
+
+      class_attribute :mass_assignment_sanitizer, :mass_assignment_sanitizers
+      self.mass_assignment_sanitizer = :logger
+      self.mass_assignment_sanitizers = {
+        :logger => LoggerSanitizer.new(self.respond_to?(:logger) && self.logger),
+        :strict => StrictSanitizer.new
+      }
     end
 
     # Mass assignment security provides an interface for protecting attributes
@@ -43,6 +49,16 @@ module MassAssignmentSecurity
     #
     #   end
     #
+    # = Configuration options
+    #
+    # * <tt>mass_assignment_sanitizer</tt> - Defines sanitize method. Possible values are:
+    #   * <tt>:logger</tt> (default) - writes filtered attributes to logger
+    #   * <tt>:strict</tt> - raise <tt>ActiveModel::MassAssignmentSecurity::Error</tt> on any protected attribute update
+    #
+    # You can specify your own sanitizer object eg. MySanitizer.new.
+    # See <tt>ActiveModel::MassAssignmentSecurity::LoggerSanitizer</tt> for example implementation.
+    #
+    # 
     module ClassMethods
       # Attributes named in this macro are protected from mass-assignment
       # whenever attributes are sanitized before assignment. A role for the
@@ -199,11 +215,13 @@ def accessible_attributes_configs
   protected
 
     def sanitize_for_mass_assignment(attributes, role = :default)
-      (mass_assignment_sanitizer || default_mass_assignment_sanitizer).sanitize(attributes, mass_assignment_authorizer(role))
-    end
-
-    def default_mass_assignment_sanitizer
-      DefaultSanitizer.new(self.respond_to?(:logger) && self.logger)
+      sanitizer = case mass_assignment_sanitizer
+                  when Symbol
+                    self.mass_assignment_sanitizers[mass_assignment_sanitizer]
+                  else
+                    mass_assignment_sanitizer
+                  end
+      sanitizer.sanitize(attributes, mass_assignment_authorizer(role))
     end
 
     def mass_assignment_authorizer(role = :default)

activemodel/lib/active_model/mass_assignment_security/sanitizer.rb

@@ -20,7 +20,7 @@ def process_removed_attributes(attrs)
       end
 
     end
-    class DefaultSanitizer < Sanitizer
+    class LoggerSanitizer < Sanitizer
 
       attr_accessor :logger
 
@@ -33,5 +33,15 @@ def process_removed_attributes(attrs)
         self.logger.debug "WARNING: Can't mass-assign protected attributes: #{attrs.join(', ')}" if self.logger
       end
     end
+
+    class StrictSanitizer < Sanitizer
+      def process_removed_attributes(attrs)
+        raise ActiveModel::MassAssignmentSecurity::Error, "Can't mass-assign protected attributes: #{attrs.join(', ')}"
+      end
+    end
+
+    class Error < StandardError
+    end
+
   end
 end

activemodel/test/cases/mass_assignment_security/sanitizer_test.rb

@@ -12,24 +12,32 @@ def deny?(key)
   end
 
   def setup
-    @sanitizer = ActiveModel::MassAssignmentSecurity::DefaultSanitizer.new
+    @logger_sanitizer = ActiveModel::MassAssignmentSecurity::LoggerSanitizer.new
+    @strict_sanitizer = ActiveModel::MassAssignmentSecurity::StrictSanitizer.new
     @authorizer = Authorizer.new
   end
 
   test "sanitize attributes" do
     original_attributes = { 'first_name' => 'allowed', 'admin' => 'denied' }
-    attributes = @sanitizer.sanitize(original_attributes, @authorizer)
+    attributes = @logger_sanitizer.sanitize(original_attributes, @authorizer)
 
     assert attributes.key?('first_name'), "Allowed key shouldn't be rejected"
     assert !attributes.key?('admin'),     "Denied key should be rejected"
   end
 
-  test "debug mass assignment removal" do
+  test "debug mass assignment removal with LoggerSanitizer" do
     original_attributes = { 'first_name' => 'allowed', 'admin' => 'denied' }
     log = StringIO.new
-    @sanitizer.logger = Logger.new(log)
-    @sanitizer.sanitize(original_attributes, @authorizer)
+    @logger_sanitizer.logger = Logger.new(log)
+    @logger_sanitizer.sanitize(original_attributes, @authorizer)
     assert_match(/admin/, log.string, "Should log removed attributes: #{log.string}")
   end
 
+  test "debug mass assignment removal with StrictSanitizer" do
+    original_attributes = { 'first_name' => 'allowed', 'admin' => 'denied' }
+    assert_raise ActiveModel::MassAssignmentSecurity::Error do
+      @strict_sanitizer.sanitize(original_attributes, @authorizer)
+    end
+  end
+
 end