Ruby on Rails latest stable (v4.2.7) - 7 notes

Declare an enum attribute where the values map to integers in the database, but can be queried by name. Example:

class Conversation < ActiveRecord::Base
  enum status: [ :active, :archived ]

# conversation.update! status: 0
conversation.active? # => true
conversation.status  # => "active"

# conversation.update! status: 1
conversation.archived? # => true
conversation.status    # => "archived"

# conversation.status = 1
conversation.status = "archived"

conversation.status = nil
conversation.status.nil? # => true
conversation.status      # => nil

Scopes based on the allowed values of the enum field will be provided as well. With the above example:


You can set the default value from the database declaration, like:

create_table :conversations do |t|
  t.column :status, :integer, default: 0

Good practice is to let the first declared status be the default.

Finally, it’s also possible to explicitly map the relation between attribute and database integer with a Hash:

class Conversation < ActiveRecord::Base
  enum status: { active: 0, archived: 1 }

Note that when an Array is used, the implicit mapping from the values to database integers is derived from the order the values appear in the array. In the example, :active is mapped to 0 as it’s the first element, and :archived is mapped to 1. In general, the i-th element is mapped to i-1 in the database.

Therefore, once a value is added to the enum array, its position in the array must be maintained, and new values should only be added to the end of the array. To remove unused values, the explicit Hash syntax should be used.

In rare circumstances you might need to access the mapping directly. The mappings are exposed through a class method with the pluralized attribute name:

Conversation.statuses # => { "active" => 0, "archived" => 1 }

Use that class method when you need to know the ordinal value of an enum:

Conversation.where("status <> ?", Conversation.statuses[:archived])

Where conditions on an enum attribute must use the ordinal value of an enum.


ENUM_CONFLICT_MESSAGE = \ "You tried to define an enum named \"%{enum}\" on the model \"%{klass}\", but " \ "this will generate a %{type} method \"%{method}\", which is already defined " \ "by %{source}."


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August 21, 2016
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Integrate enum with PostgreSQL Enumerated Types

Extract from:


There are 2 things that we need to do before we can use ActiveRecord::Enum with PostgreSQL Enumerated Types: database migration and enum declaration.

First, let’s create the database migration:

$ bundle exec rails generate migration AddGenderToUsers gender:gender

Next, edit the generated migration to add the type:

# db/migrate/20150619131527_add_gender_to_users.rb
class AddGenderToUsers < ActiveRecord::Migration
  def up
    execute <<-SQL
      CREATE TYPE gender AS ENUM ('male', 'female', 'not_sure', 'prefer_not_to_disclose');

    add_column :users, :gender, :gender, index: true

  def down
    remove_column :users, :gender

    execute <<-SQL
      DROP TYPE gender;

Once you’re finished with that, run the migration:

$ bundle exec rake db:migrate

Now, we have completed the database migration. The next step is to declare an enum in the User model. Earlier, we used both the Array and Hash forms to declare an enum. For the integration to work, we need to declare an enum using the Hash form:

# app/models/user.rb
class User < ActiveRecord::Base
  enum gender: {
    male:                   'male',
    female:                 'female',
    not_sure:               'not_sure',
    prefer_not_to_disclose: 'prefer_not_to_disclose'

Finally, we can store ActiveRecord::Enum values using PostgreSQL Enumerated Types. As a bonus, all helper methods provided by ActiveRecord::Enum still work as expected.

February 14, 2016
1 thank

Text values for enum

There is way to have text values for enum. It is useful to have localized select options and latin values in database. 1) User model: enum kind: { ‘текст’=>‘text’, ‘изображение’=>‘picture’, ‘звук’=>‘audio’, ‘видео’=>‘video’ } 2) Edit view: <%= select_tag ‘user[kind]’, options_for_select(User.kinds, @user.kind) %>

September 13, 2016 - (v3.2.1 - v4.2.7)
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Search Kick Gem – To Make Your Search Intelligent On Rails App

Search kick Gem is a Ruby gem that runs on top of Elasticsearch and makes it easy to make searches in a Rails-friendly fashion. In addition, it allows you to add more features including analytics, autocomplete, and personalized results. Searchkick realizes what your users are searching for. As more individuals hunt, it gets more brilliant and the outcomes improve. It’s benevolent for designers – and supernatural for your users. It handles stemming, special characters, extra whitespace, misspellings, custom synonyms. To get started, make sure that you have Elasticsearch installed on your home computer. Depending on your operating system, the installation process is slightly different and make sure you have at least Java 7. Once you have that done, add and install searchick to your Rails application by adding the following to your Gemfile and running bundle install.


When you have both installed and ready to go, you need to indicate which models you might want to be able to search through in your application. Just add searchkick to the model file to make it work. Then, we need to reindex the models so that Elasticsearch can run properly. In your terminal, run:

rake searchkick:reindex:all

Seeking with searchkick is entirely straightforward. Basically run YourModel.search, trailed by the parameters of the search and any filters that you want to add on. For instance, one of more complex searches is below:

 @offers = Offer.search params[:search],
 page: params[:page], per_page: 10,
 order: {starttime: :desc},
 fields: [{offer_name: :word_start}, 
offer_request_name: :word_start}:price],
 where: {
 starttime: {
 gte: DateTime.strptime(params[:fromdate],‘%m/%d%Y’),
 lte: DateTime.strptime(params[:todate],‘%m/%d/%)

In this search, we take the search query of the user with params[:search], and look through of the lessons with the following conditions:

Read More From Here : http://www.railscarma.com/blog/technical-articles/search-kick-gem-to-make-your-search-intelligent-on-rails-app/

October 3, 2016
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How To Generate a Swagger Docs For Rails API

Making API for a Rails application is simple for a Ruby on Rails developer. In any case, how different clients/customers will know whether the API is working fine or not without a customer side application. Is there any answer for this which I can report for API inside the Rails application, The answer is yes we have numerous instruments and methodologies however I would favor swagger UI.

In this article I am going to disclose how to make Rails API documentation using swagger UI.

Prerequisites:- I am going to use one sample posts application which serves API calls.

Gem:- To Integrate swagger UI for Rails API I am using a gem called swagger-docs. Add this gem to your Gemfile in your application and do bundle install.

Swagger initializer file:- After bundling the gem create an initializer in config/initializers(e.g. swagger.rb) and specify the following options:

#File config/initializers/swagger.rb


"1.0" => {

# the extension used for the API

:api_extension_type => :json,

# the output location where your .json files are written  to

:api_file_path => "public/apidocs",

# the URL base path to your API

:base_path => "http://localhost:3000",

# if you want to delete all .json files at each generation

:clean_directory => true,

# add custom attributes to api-docs

:attributes => {

:info => {

"title" => "Your application title",

"description" => "Rails API documention with Swagger UI.",

"termsOfServiceUrl" => "",

"contact" => ""





Refer below url for the list of configarations


swagger_controller and swagger_API are helpers to provide swagger UI documentation.

module Api

module V1

class PostsController < ApplicationController

respond_to :json

swagger_controller :posts, 'Post Controller'

swagger_api :create do

summary 'Creating posts'

notes 'Should be used for creating posts'

param :form, 'post[name]', :string, :required, 'name'

param :form, 'post[publish]', :boolean, :required, 'publish'


swagger_api :index do

summary 'Get all the posts'

notes 'Should be used for fetching all posts'

param :header, :Authoraization, :string, :required, 'Authoraization'

response :unauthorized

response :ok, "Success"


swagger_api :show do

summary 'Get all the posts'

notes 'Should be used for fetching a post'

param :path, :id, :string, :id

response :unauthorized

response :ok, "Success"


swagger_api :destroy do

summary 'Destroy the post'

notes 'Should be used for destroying a post'

param :path, :id, :string, :id

response :unauthorized

response :ok, "Success"





Read More From Here http://goo.gl/dMVHon

October 17, 2016
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How to generate & add sitemap to your Rails Application

Generate Sitemap: Required Gem: Sitemap generator:- github.com/kjvarga/sitemap_generator

SitemapGenerator is the easiest way to generate Sitemaps in Ruby. Rails integration provides access to the Rails route helpers within our sitemap config file and automatically makes the rake tasks available to us. Or if we prefer to use another framework, we can! We can use the rake tasks provided or run our sitemap configs as plain ruby scripts.

Sitemaps XML format:

The Sitemap protocol format consists of XML tags. All data values in a Sitemap must be entity-escaped. The file itself must be UTF-8 encoded.

The Sitemap must: Begin with an opening <urlset> tag and end with a closing </urlset> tag. Specify the namespace (protocol standard) within the <urlset> tag. Include a <url> entry for each URL, as a parent XML tag. Include a <loc> child entry for each <url> parent tag.

All other tags are optional. Also, all URLs in a Sitemap must be from a single host, such as www.xyz.com or estore.xyz.com. For more details: http://www.sitemaps.org/protocol.html

How to add a sitemap to a Rails app:

1, View for your sitemap:

# app/views/mysitemap/index.xml.erb

2, At your Controller: Let it be our object in view is @articles variable. It needs to get that from a mysitemap controller:

# app/controllers /mysitemap_controller.rb
MysitemapController <  ApplicationController
 layout nil
  def index
 headers['Content-Type'] =  'application/xml'
respond_to do |format|
 format.xml {@articles =  Article.all}

3, Add a route:

# config/routes.rb
get 'sitemap.xml', :to =>  'sitemap#index', :defaults =>  {:format  => 'xml'}

How to convert XML file to HTML: Read From Here http://goo.gl/Vp3chb

September 23, 2016 - (v3.2.3 - v4.0.2)
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Usage of SQL and NoSQL Databases in single rails application(MySQL, PostgreSQL and MongoDB)

There are distinctive reasons why you should think about having various databases in your Ruby on Rails application. In my situation, I expected to store large quantities of data.

Consider default database is MySQL. In our application database.yml file write connections for MySQL in normal way. After that, for connecting postgresql in the same application we need to create custom files.

Create the custom database files to connect postgresql

We’re going to set up a second database called “Stats”

First of all, create the file config/database_stats.yml and populate it as you do with the primary database’s config file.

Your file will look something like this:

adapter: postgresql
encoding: utf8
reconnect: false
database: db_info_development
pool: 5
host: localhost
username: postgres

We’re now going to create a directory that will hold the schema and all the migrations of the Stats database.

Create directory with name db_stats in the rails root and copy the structure as mentioned below


The created files should be empty.

Add Rake Tasks

For handling stats database, we need to write custom tasks for creation, migrations and other functionalities.

Create a file lib/tasks/db_stats.rake with the below content

namespace :stats do

namespace :db do |ns|

task :drop do

task :create do

task :setup do

task :migrate do

task :rollback do

task :seed do

task :version do

namespace :schema do
task :load do

task :dump do

namespace :test do
task :prepare do

# append and prepend proper tasks to all the tasks as defined above

ns.tasks.each do |task|
task.enhance [“stats:set_custom_config”] do

task :set_custom_config do

# save current vars

@original_config = {
env_schema: ENV[‘SCHEMA’],
config: Rails.application.config.dup

# set config variables for custom database

ENV[‘SCHEMA’] =db_stats/schema.rb”
Rails.application.config.paths[‘db’] = [“db_stats”]
Rails.application.config.paths[‘db/migrate’] = [“db_stats/migrate”]
Rails.application.config.paths[‘db/seeds’] = [“db_stats/seeds.rb”]
Rails.application.config.paths[‘config/database’] = [“config/database_stats.yml”]

task :revert_to_original_config do
# reset config variables to original values
ENV[‘SCHEMA’] = @original_config[:env_schema]
Rails.application.config = @original_config[:config]

Once all of this setup is done, we can create the stats database and run its first migration:

$ rake stats:db:create
$ rake stats:db:migrate

This will generate the Stats database schema file in db_stats/schema.rb.

Add a custom migration generator We cannot use rails generator because the path hardcodes the db/migrate. Read more From Here http://goo.gl/jVCVRJ

September 1, 2016
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Previewing Emails in Rails Applications With the Mail_View Gem

Sending an email from an application through a development or staging environment can be cumbersome especially when you want to preview the mail before you hit the send button. With the gem ‘mail_view, you can easily preview emails right from your development environment. Previewing mail is important to ensure that you are sending the right email and to the right person.

Never send a mail in dark anymore with the ‘mail_view gem! Check out more below on how it can be implemented in your application during the development stage.

Rails Email Preview helps us to quickly view the email in web browser in development mode.

  1. Add “gem ‘rails_email_preview’, ‘~> 0.2.29’ “ to gem file and bundle install.

  2. Run “rails g rails_email_preview:install” this creates initializer in config folder and add routes.

  3. Run “rails g rails_email_preview:update_previews” this crates mailer_previews folder in app directory.

Generator will add a stub to each of your emails, then u populate the stub with mock data.


class UserMailerPreview
def invitation
UserMailer.invitation mock_user(‘Alice’), mock_user(‘Bob’)

def welcome
UserMailer.welcome mock_user

def mock_user(name =Bill Gates’)
fake_id User.new(name: name, email:user#{rand 100}@test.com”)

def fake_id(obj)
obj.define_singleton_method(:id) { 123 + rand(100) }
  1. Parameters in search query will be available as an instance variable to preview class.

Ex: if we have a URL like “/emails/user_mailer_preview-welcome?user_id=1” @user_id is defined in welcome method of UserMailerPreview it helps us to send mail to specific user.

class UserMailerPreview
def welcome
user = @user_id ? User.find(@user_id) : mock_user
  1. To access REP url’s like this

  2. We can send emails via REP, this will use environment mailer settings. Uncomment this line in the initializer to disable sending mail in test environment.

    config.enable_send_email = false

References :

  1. github.com/glebm/rails_email_preview

  2. richonrails.com/articles/action-mailer-previews-in-ruby-on-rails-4-1

Read More From Here>>> http://goo.gl/KQBk5S