Refactored username validations to avoid repeated code

app/models/group.rb

@@ -145,10 +145,7 @@ class Group < ActiveRecord::Base
   protected
 
   def name_format_validator
-    validator = UsernameValidator.new(name)
-    unless validator.valid_format?
-      validator.errors.each { |e| errors.add(:name, e) }
-    end
+    UsernameValidator.perform_validation(self, 'name')
   end
 
   # hack around AR

app/models/user.rb

@@ -399,10 +399,7 @@ class User < ActiveRecord::Base
   end
 
   def username_format_validator
-    validator = UsernameValidator.new(username)
-    unless validator.valid_format?
-      validator.errors.each { |e| errors.add(:username, e) }
-    end
+    UsernameValidator.perform_validation(self, 'username')
   end
 
   def email_confirmed?
@@ -591,17 +588,17 @@ class User < ActiveRecord::Base
 
   private
 
-    def self.discourse_hub_nickname_operation(&block)
-      if SiteSetting.call_discourse_hub?
-        begin
-          yield
-        rescue DiscourseHub::NicknameUnavailable
-          false
-        rescue => e
-          Rails.logger.error e.message + "\n" + e.backtrace.join("\n")
-        end
+  def self.discourse_hub_nickname_operation
+    if SiteSetting.call_discourse_hub?
+      begin
+        yield
+      rescue DiscourseHub::NicknameUnavailable
+        false
+      rescue => e
+        Rails.logger.error e.message + "\n" + e.backtrace.join("\n")
       end
     end
+  end
 end
 
 # == Schema Information

app/models/username_validator.rb

@@ -1,4 +1,18 @@
 class UsernameValidator
+  # Public: Perform the validation of a field in a given object
+  # it adds the errors (if any) to the object that we're giving as parameter
+  #
+  # object - Object in which we're performing the validation
+  # field_name - name of the field that we're validating
+  #
+  # Example: UsernameValidator.perform_validation(user, 'name')
+  def self.perform_validation(object, field_name)
+    validator = UsernameValidator.new(object.send(field_name))
+    unless validator.valid_format?
+      validator.errors.each { |e| object.errors.add(field_name.to_sym, e) }
+    end
+  end
+
   def initialize(username)
     @username = username
     @errors = []