Rails 5 Create module and class level variables
Rails already provides methods for creating class level and module levelvariables in the form ofcattr** and mattr** suite of methods. In Rails 5, we can go a step further and createthread specific class or module level variables. Here is an example which demonstrates an example on how to use it. module CurrentScope thread_mattr_accessor :user_permissionsendclass ApplicationController < ActionContr
Rails 5 supports adding comments in migrations
Database schemas change rapidly as project progresses. And it can be difficultto track purpose of each table and each column in a large project with multipleteam members. The solution for this problem is to document data models right from Railsmigrations. Solution in Rails 4You can add comments in Rails 4.x migrations using gems likemigration_comments andpg_comment. Solution in Rails 5Rails 5 allo
Rails 5 adds finish option in find_in_batches
In Rails 4.x we had start option in find_in_batches method. Person.find_in_batches(start: 1000, batch_size: 2000) do |group| group.each { |person| person.party_all_night! }endThe above code provides batches of Person starting from record whose value ofprimary key is equal to 1000. There is no end value for primary key. That means in the above case all therecords that have primary key value greater
Rails 5 adds ArrayInquirer and provides friendlier way to check contents in an array | BigBinary Blog
Rails 5 introduces Array Inquirerthat wraps an array object and provides friendlier methods to check for thepresence of elements that can be either a string or a symbol. pets = ActiveSupport::ArrayInquirer.new([:cat, :dog, 'rabbit'])> pets.cat?#=> true> pets.rabbit?#=> true> pets.elephant?#=> falseArray Inquirer also has any? method to check for the presence of any of thepassed arguments as elemen
Rails 5 introduces country_zones helper method
Before Rails 5, we could fetch all time zones for US by using us_zones methodas follows. > puts ActiveSupport::TimeZone.us_zones.map(&:to_s)(GMT-10:00) Hawaii(GMT-09:00) Alaska(GMT-08:00) Pacific Time (US & Canada)(GMT-07:00) Arizona(GMT-07:00) Mountain Time (US & Canada)(GMT-06:00) Central Time (US & Canada)(GMT-05:00) Eastern Time (US & Canada)(GMT-05:00) Indiana (East)Such functionality of gett
Rails 5 provides fragment caching in Action Mailer views
Fragment cache helps in caching parts of the view instead of caching the entireview. Fragment caching is used when different parts of the view need to becached and expired separately. Before Rails 5, fragment caching was supportedonly in Action View templates. Rails 5 providesfragment caching in Action Mailer views. To use this feature, we need to configure our application as follows. config.actio
Rails 5 adds OR support in Active Record
Rails 5has added OR methodto Active Relation for generating queries with OR clause. >> Post.where(id: 1).or(Post.where(title: 'Learn Rails')) SELECT "posts".* FROM "posts" WHERE ("posts"."id" = ? OR "posts"."title" = ?) [["id", 1], ["title", "Learn Rails"]]=> <ActiveRecord::Relation [#<Post id: 1, title: 'Rails'>]>This returns ActiveRecord::Relation object, which is logical union of tworelations.
Rails 5 Renaming transactional fixtures to tests
In Rails 4.x we have transactional fixtures that wrap each test in a databasetransaction. This transaction rollbacks all the changes at the end of the test.It means the state of the database, before the test is same as after the test isdone. By default this functionality is enabled. We can choose to disable it in a testcase class by setting the class attribute use_transactional_fixtures tofalse cl
ApplicationRecord in Rails 5
Rails 5 beta-1 wasrecently released and one of the notable change was introduction ofApplicationRecord. Up to Rails 4.2, all models inherited from ActiveRecord::Base. But startingfrom Rails 5, all models will inherit from ApplicationRecord. class Post < ApplicationRecordendWhat happened to ActiveRecord::Base ? Well not much changed in reality. Following file will be automatically added tomodels in
Rails 5 supports bi-directional destroy dependency
In Rails 4.x, it is not possible to have destroy dependency on both sides of a bi-directional association between the two models as it would result in an infinite callback loop causing SystemStackError: stack level too deep. 1 2class User < ActiveRecord::Base 3 has_one :profile, dependent: :destroy 4end 5 6class Profile < ActiveRecord::Base 7 belongs_to :user, dependent: :destroy 8end 9 Copy 1 2>>
Rails 5 Updating a record without updating timestamps
In Rails 4.x, when we save an ActiveRecord object then Rails automaticallyupdates fields updated_at or updated_on. >> user = User.new(name: 'John', email: 'john@example.com')>> user.save INSERT INTO "users" ("name", "created_at", "updated_at", "email") VALUES (?, ?, ?, ?) [["name", "John"], ["created_at", 2016-03-16 09:12:44 UTC], ["updated_at", 2016-03-16 09:12:44 UTC], ["email", "john@example.co
Rails 5 Retrieving info of failed validations
Let's look at a validation example in Rails 4.x. class User < ActiveRecord::Base validates :email, presence: trueend>> user = User.new>> user.valid?=> false>> user.errors.messages=> {:email=>["can't be blank"]}In this case, we do not get any information about the type of failed validationas ActiveModel#Errors only gives the attribute name and the translated errormessage. This works out well for no
Rails 5 officially supports MariaDB
MariaDB is an open source fork of the MySQL database andit acts as a drop-in replacement for MySQL. After the Oracle'stake overofMySQLthere was some confusion about the future of MySQL. To remove any ambiguityabout whether in future MySQL will remain free or not MariaDBwas started . Some of you might be wondering what advantages MariaDB offers over MySQL.Here isan article which lists10 reasonsto m
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BigBinary Blog: Insights on Ruby on Rails, React & More
BigBinary Blog: Insights on Ruby on Rails, React & More
Rails 5 adds another base class Application Job for jobs
[Srijan Wednesday Webinar] Rails 5: What s in It for Me?