Many times, we need to skip validation as well as callbacks while saving the object, due to the requirement of a Ruby on Rails application. In Rails 3.x, to skip validation we can use (:validate => false) and to skip callbacks we tend to use ActiveSupport::Callbacks::ClassMethods#skip_callback (http:\/\/apidock.com\/rails\/ActiveSupport\/Callbacks\/ClassMethods\/skip_callback).<\/p>\n
ActiveSupport::Callbacks::ClassMethods#skip_callback<\/p>\n
This method can get us into trouble, as it is not thread-safe. So to skip callbacks, there is no option as (:callbacks => false) or (:skip_callbacks => true) . In order to achieve similar functionality of skipping callbacks following gems\/code snippets are widely referred:<\/p>\n
Since I have been working with Rails for quite some time now, and been observing this situation quite frequently. Based on my observations, I tend to conclude the following on above references and methods,<\/p>\n
INSTALLATION<\/p>\n
$ gem install sneaky-save<\/pre>\nNow add it to your Gemfile with:<\/p>\n
gem 'sneaky-save'<\/pre>\nRun the bundle command to install it.<\/p>\n
Once you install sneaky-save and add it to your Gemfile, you are ready to use it in your application.<\/p>\n
USAGE<\/p>\n
# Create\r\n\r\n@user = User.new\r\n@user.first_name = 'UserFirstName'\r\n@user.last_name = 'UserLastName'\r\n@user.sneaky_save\r\n\r\n# Update\r\n\r\n@user = User.find(123) # say record id = 123 \r\n@user.first_name = 'NewUserFirstName'\r\n@user.last_name = 'NewUserLastName'\r\n@user.sneaky_save<\/pre>\nLOGIC<\/p>\n
All the logic is in SneakySave module (https:\/\/github.com\/partyearth\/sneaky-save\/blob\/master\/lib\/sneaky-save.rb)<\/p>\n
def sneaky_save\r\n begin\r\n # If it is a new record then create a new record else update changed attributes\r\n new_record? ? sneaky_create : sneaky_update\r\n rescue ActiveRecord::StatementInvalid\r\n false\r\n end\r\nend<\/pre>\nWe can use sneaky_save on new or existing object. Depending on the object, if it is a new object then to create object sneaky_create is used to generate SQL insert query. If the object is an existing object then SQL update query is generated.<\/p>\n
# File https:\/\/github.com\/partyearth\/sneaky-save\/blob\/master\/lib\/sneaky-save.rb, line 26<\/p>\n
def sneaky_create\r\n\r\n if self.id.nil? && connection.prefetch_primary_key?(self.class.table_name) \r\n self.id = connection.next_sequence_value(self.class.sequence_name) \r\n end\r\n\r\n attributes_values = send :arel_attributes_values\r\n\r\n # Remove the id field for databases like Postgres which will raise an error on id being NULL \r\n if self.id.nil? && !connection.prefetch_primary_key?(self.class.table_name) \r\n attributes_values.reject! { |key,_| key.name == 'id' }\r\n end\r\n\r\n # Uses ActiveRecord's insert() method to generate insert SQL query \r\n new_id = if attributes_values.empty?\r\n self.class.unscoped.insert connection.empty_insert_statement_value \r\n else\r\n self.class.unscoped.insert attributes_values\r\n end\r\n\r\n @new_record = false\r\n !!(self.id ||= new_id)\r\n\r\nend<\/pre>\nHere the main functioning is done by Model.insert(). It is ActiveRecord::ConnectionAdapters::DatabaseStatements#insert method that generates SQL insert query for creating a new record.<\/p>\n
# File https:\/\/github.com\/partyearth\/sneaky-save\/blob\/master\/lib\/sneaky-save.rb, line 50<\/p>\n
def sneaky_update\r\n # Handle no changes.\r\n return true if changes.empty?\r\n # Here we have changes --> save them.\r\n pk = self.class.primary_key\r\n original_id = changed_attributes.has_key?(pk) ? changes[pk].first : send(pk) \r\n !self.class.update_all(attributes, pk => original_id).zero?\r\nend<\/pre>\nHere Model.update_all() is called for generating SQL update query and update the given record. These methods are called from ActiveRecord::Base#update_all<\/p>\n
HOW IT WORKS?<\/p>\n
‘sneaky_save’ method internally calls ‘sneaky_create’ and ‘sneaky_update’ as per object state. In ‘sneaky_create’ method, INSERT SQL query is generated and executed. Direct INSERT SQL is executed without involving Model, thus no validation or callback is triggered. In ‘sneaky_update’ method, UPDATE SQL query are generated and executed to manipulate database. Here it does not instantiate Model object, hence does not trigger any validation or callback.<\/p>\n
ADVANTAGE<\/p>\n
Following existing methods which are available for an update but with their own limitations.<\/p>\n
update_attributes : Validation is invoked. Callbacks are invoked.<\/p>\n
update_attribute : Validation is skipped. Callbacks are invoked.<\/p>\n
update_column : Validation is skipped. Callbacks are skipped.<\/p>\n
update_columns : Validation is skipped. Callbacks are skipped. (available in Rails4)<\/p>\n
update_all : Validation is skipped. Callbacks are skipped.<\/p>\n
sneaky_save: sneaky-save is easy to use and have clean syntax. It can be called directly on the object without passing any parameters to it.<\/p>\n
DRAWBACKS: Does not reload updated record by default. Does not save associated collections. Saves only belongs_to relations. All the callbacks are skipped, does not have any option to trigger\/skip selected callbacks<\/p>\n
These are mostly my observations so pros and cons may not be limited to what I have posted above \ud83d\ude42 . I am willing to learn the feedback of other community guys, ————————-<\/p>\n","protected":false},"excerpt":{"rendered":"
In a Ruby on Rails application, we need to skip validation as well as callbacks while saving the object.
\nIn Rails 3.x, commonly used method to skip callbacks is ActiveSupport’s skip_callback method, but this method could cause problems as its not thread-safe. This post talks about alternative way to achieve the purpose.<\/p>\n","protected":false},"author":9192191,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_links_to":"","_links_to_target":""},"categories":[3],"tags":[14,20,98],"class_list":["post-850","post","type-post","status-publish","format-standard","hentry","category-technology","tag-rails-3","tag-ruby-on-rails","tag-skip-callback"],"_links":{"self":[{"href":"https:\/\/www.allerin.com\/blog\/wp-json\/wp\/v2\/posts\/850","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.allerin.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.allerin.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.allerin.com\/blog\/wp-json\/wp\/v2\/users\/9192191"}],"replies":[{"embeddable":true,"href":"https:\/\/www.allerin.com\/blog\/wp-json\/wp\/v2\/comments?post=850"}],"version-history":[{"count":9,"href":"https:\/\/www.allerin.com\/blog\/wp-json\/wp\/v2\/posts\/850\/revisions"}],"predecessor-version":[{"id":913,"href":"https:\/\/www.allerin.com\/blog\/wp-json\/wp\/v2\/posts\/850\/revisions\/913"}],"wp:attachment":[{"href":"https:\/\/www.allerin.com\/blog\/wp-json\/wp\/v2\/media?parent=850"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.allerin.com\/blog\/wp-json\/wp\/v2\/categories?post=850"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.allerin.com\/blog\/wp-json\/wp\/v2\/tags?post=850"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}