Notes posted to Ruby on Rails

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April 19, 2019
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Thanks davinjay!

Your note was SUPER helpful so I wanted to leave more than just a “1 thank”.


January 17, 2019 - (v4.2.7)
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This method has been completely removed from Rails 5 onwards

Completely removed from Rails from 5 onwards. See issue: github.com/rails/rails/issues/18336

Just remove from your codebase, or protect with `private` keyword

June 4, 2018 - (v4.2.7)
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Upload Files Directly To S3 Using Paperclip And Dropzone.js

Upload Files Directly To S3 Using Paperclip And Dropzone.js

by | Dec 22, 2017 | Technical Articles | 0 comments

It’s usually the small time-consuming tasks that frustrate us the most. Such as uploading a file to S3; the requirement is pretty simple but the method chosen to upload the file will decide the efficiency of the task. As uploading files is a feature that most applications require, RailsCarma has compiled a brief tutorial on one of the best methods of getting this task done efficiently: using Paperclip and Dropzone.js.

Paperclip is a popular choice for uploading images and files as it offers great features to handle the attachments;paperclip’ gem is the go-to option. Paperclip allows you to upload multiple images and files, generate thumbnails and even automatically resize the images. It boasts of a large and active community making it the top choice of most developers.
Dropzone.js is an open source library with file drag & drop (with image preview) features.
Amazon S3 is a simple storage device for data storage. We can use it to retrieve images and all type of files.

Why Paperclip?

Paperclip is a popular file uploading tool for the following reasons:

Supports File Caching:
If a form fails to validate, we don’t want the user to pick his file again and re-upload it. Therefore, file caching is necessary from a UX standpoint. And it also conserves the bandwidth.

Processes Images
Paperclip is able to resize and crop images to several different formats thus allowing the developer to choose the library.

Simplifies The Task!
Paperclip gem does not pollute your code and is easy to test!

Allows File Processing
Paperclip allows file processing for EXIF data extraction and thumbnail creation of uploaded PDFs, PSDs, DOCs, XLSXs.

Provides CDN & Storage-Service Support 
This is a big plus as we want to keep the bandwidth to our servers as low as possible and avoid possible data loss due to server failure.

Offers On-The-Fly Processing
Paperclip processes images and files on a per-request basis. This is an innovative feature that enables developers to create custom content that adapts best to different situations.

What Are The Dropzone Asynchronous Events?

addedfile:  When a file is added to the list.
removedfile: Used whenever a file is removed from the list. You can listen to this and delete the file from your server if you want to.
thumbnail: When the thumbnail has been generated. It receives the data URL as second parameter.
error: An error occurred receives the error message as the second parameter. And if the error was due to xmlhttprequest, the xhr object is received as the third parameter.
processing: When a file is processed (since there is a queue, not all files are processed immediately). This event was previously called processingfile.
drop: The user dropped something onto the drop zone.

How Can We Configure Paperclip In Our Application?

has_attached _file: asset
:storage => :s3
:S3_host_name => ENV[“S3_HOST_NAME”]
:S3_region => ENV[“S3_REGION”]
:S3_protocol => ENV[“S3_PROTOCOL”]
:path =>:account_id/:class/:source_id/:attachment/:file_name”,:s3_headers => {‘ContentDisposition’ =>attachment’,content-type’ =>‘application/octet_stream’},
:bucket => ENV[“S3_BUCKET”],
:s3_credentials => Proc.new{|a| a.instance.s3_credentials}
Do_not_validate_attachment_file_type :asset
def s3_credentials
{:access_key_id => ENV[“S3_ACCESS_KEY_ID”], :secret_access_key => ENV[“S3_SECRET_ACCESS_KEY”]}


How Can We Handle Custom Paths In Our Application? Read More from here http://www.railscarma.com/blog/technical-articles/upload-files-directly-s3-using-paperclip-dropzone-js/

May 3, 2018
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April 17, 2018
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When using ActionView::Base.new to render templates views

when calling this method to render templates to a string. in order to use any helper methods you need to add them to the view like this

view = ActionView::Base.new(ActionController::Base.view_paths, {})
view.class_eval do  
  # include any needed helpers (for the view)
  include ApplicationHelper

source: http://peden.biz/rendering-a-rails-view-from-a-script/

March 22, 2018
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Each attribute has a `reset_<attribute>!` method on it as well.

So if the attribute is name you can call reset_name! on the object to reset the dirty changes.

February 5, 2018
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method is working until rails 4

deprecation message and rails line (till v 2.3.8) is not correct. Method exist and working until rails 4.

January 29, 2018 - (<= v3.2.13)
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Correction: Getting just the ordinal on Rails 3.

The ordinal method isn’t publicly available in Rails 3 so you can do something like this:

ordinalize(1).last(2) #=> "st"

ordinalize(20).last(2) #=> "th"
December 20, 2017
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Effectively identical to Hash#as_json

As of 5.2.0.beta, there is no ActiveRecord::Relation specific implementation. This will result in Object#as_json , which will convert the relation to a hash and call Hash#as_json .

class Object
  def as_json(options = nil) #:nodoc:
    if respond_to?(:to_hash)
December 20, 2017
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Counting with select

If you try to write

Model.select('field_one', 'field_two AS something').count

it will fail (at least for Rails 5.0) with the message PG::SyntaxError: ERROR: syntax error at or near “AS”. In order to fix that issue, you should write

Model.select('field_one', 'field_two AS something').count(:all)
December 9, 2017 - (<= v3.2.13)
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Getting just the ordinal on Rails 3.

The ordinal method isn’t publicly available in Rails 3 so you can do something like this:

ordinal(1).last(2) #=> "st"

ordinal(20).last(2) #=> "th"
August 10, 2017 - (v2.2.1 - v4.2.7)
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The Exception Notifier plugin provides a mailer object and a default set of templates for sending email notifications when errors occur in a Rails application. It is basically a monitoring tool, which keeps on watching the application and whenever it finds any error, it triggers that error to PagerDuty. To use Exception Notification and PagerDuty in your app, you need to add this gem below:

gem 'exception_notification', '~> 4.1.0'

gem  'pagerduty''

To get the email notifications, you need to include the line below in the development env:

Rails.application.config.middleware.use  ExceptionNotification::Rack,
                 :email => {
                  :email_prefix => "[PREFIX] ",
                  :sender_address => %{"notifier"  <notifier@example.com>},
                  :exception_recipients => %w{exceptions@example.com},
                  :pd => {
                           # simple notifier options

You can modify sender’s and recipient’s address.

Rails App+PagerDuty

Use the code below in your app with exception notifier to connect with PagerDuty:

require "pagerduty"
module ExceptionNotifier
      Class PdNotifier
          def initialize(options)
            @pagerduty =   Pagerduty.new("0bdcfdacf1b144d7822dfdfa5ed0ab1e")# Service api key
           # do something with the options...
        def call(exception, options={})
           @pagerduty.trigger(exception.message, details:  { backtrace: exception.backtrace })


PagerDuty is alert dispatching tool used by operations team/OnCall Engineers to manage the applications and it is popular because of its reliable & rich services(Scheduling,Alerting,Reporting,Call Routing , Feedback & response time).

Create your Free account from app.pagerduty.com/ and integrate with your application to get the flow , how Incident is triggered.

June 28, 2017
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How to use Textacular Gem to search data in your Rails Application

We might have heard about a lot many gems which let us implement search functionality in our rails application; for example: searchkick, elasticsearch-rails, ransack and finally, sunspot to work with solr search engine. All these gems have their own advantages. Both searchkick and elasticsearch use redis to search the data as well as need to perform a ‘reindex’ while inserting new data. In one of my recent projects, I happened to use a gem called as Textacular. It’s simple and very easy to use. Textacular Gem:

It is a gem that provides full text search capabilities for PostgreSQL Database. It basically caters to extend the scope of the work performed by activerecord, in a rather friendly manner. It works on heroku as well. This gem works only on PostgreSQL For working with it, let’s first grab the latest textacular gem from rubygems.org/gems/textacular and add it to the gemfile.

gem 'textacular'
    bundle install

Textacular gem provides us with quite a few methods to search the data. So, all our models have the access to use those methods.

basic_search advanced_search fuzzy_search

Usage: Basic_search: It searches based on the input text.

User.basic_search(‘abc’) # Searches on all the model column attributes

User.basic_search(last_name: 'abc', first_name: 'xyz')

Advanced_search: Here, we can use postgres syntaxes like !, & and | (and, or and, not) and then, some others based on the requirement. It converts user’s search DSL into Pg syntax. For this, we need to make sure that the necessary exceptions should be used to handle the syntax errors.

User.advanced_search(last_name: 'text1|text2’) - It  searches with the text1 or text2 on last_name on User  model.

User.advanced_search(last_name: '!text2’) - It searches for the records whose last_name is not text2.

These searches can be chainable as shown below:

User.advanced_search(last_name: 'text1|text2’).basic_search(last_name: 'abc', first_name: 'xyz')

Fuzzy_search: We need to install pg_trgm module to work with fuzzy_search. Run the command below to install this module. It searches for partial appearance of your text in the DB.

rake textacular:create_trigram_migration  
rake db:migrate

Now, we are ready to use fuzzy_search.


By default, fuzzy search, searches for the records which are 30% of the search text matches with respect to the entire content. We can set this threshold limit by using the command below.

ActiveRecord::Base.connection.execute("SELECT set_limit(0.6);")

So, it expects 60% of search text to match with the original content. We can use OR condition to search on multiple columns. Need to pass a hash with columns with input text as param one and pass second param as a false. It takes AND, if you miss second param or if it True.

User.fuzzy_search({first_name: 'user', last_name: 'test'}, false)

User.fuzzy_search(first_name:user’, last_name: 'test') - It takes AND condition.

By default, the Textacular searches in all text and string columns. We can alter its default behaviour by overriding the searchable_columns method in the model.

def self.searchable_columns
   [:title, :body]

We can override self.searchable_language in the model to set proper dictionary settings.

def self.searchable_language 

Read More : http://www.railscarma.com/blog/technical-articles/how-to-use-textacular-gem-to-search-data-in-your-rails-application/

March 29, 2017
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multiple select has a hidden

It’s unclear if “select_tag” does this but the normal select method also generates a hidden variable if the “multiple” option is set, see http://apidock.com/rails/ActionView/Helpers/FormOptionsHelper/select

March 29, 2017
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not submitted even if non-multiple in certain cases.

As a note, just for followers, even if a select is not “multiple” if it is “unselected” (ex: in javascript you can set its value like document.getElementById(‘select_id’).value = ‘a non option’; ). And if that form is submitted, the browser also seems to not send anything about it to the server. So it’s for non-multiples as well, just this case is rare since typically the select will default to its “first value” and then users can only change it another known value, so typically you won’t run into that. This isn’t related to rails but thought I’d mention it.

March 2, 2017
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Converting Hash to Struct in Ruby

With the fact we know about the two, many will perhaps prefer using struct rather than hash. But what we want to focus here is that behind the low performance given by hash, they still can become advantageous. If you can’t use it on its own little way, then convert it into struct so better usability can be achieved.

If you have already defined the struct and you wanted to initiate converting hash to struct, we can help you by using the following methods in a given example below. If you wanted to convert has to a struct in Ruby, let us say for example we have a given of:

h = { :a => 1, :b => 2 }

and want to have a struct such as:

s.a == 1
s.b == 2

To convert, you can do any of these methods: Conversion Method 1:

On this method, the result will appear to be OpenStruct and not specifically as struct:

pry(main)> require 'ostruct'
pry(main)> s = OpenStruct.new(h)
=> #<OpenStruct a=1, b=2>
pry(main)> puts s.a, s.b

Conversion Method 2:

If you have struct defined already and want to start something with a hash, you can follow this:

Person = Struct.new(:first_name, :last_name, :age)

person_hash = { first_name: "Foo", last_name: "Bar", age: 29 }

person =  Person.new(*person_hash.values_at(*Person.members))

=> #<struct Person first_name="Foo", last_name="Bar", age=29>

Conversion Method 3:

Since the hash key order was guaranteed in the Ruby 1.9+, you can follow this:

s = Struct.new(*(k = h.keys)).new(*h.values_at(*k))

The hash to struct conversion example we provided can help, but if you want a more extensive idea, come to professionals for formal assistance. Read More From Here http://www.railscarma.com/blog/technical-articles/guide-converting-hash-struct-ruby/

February 1, 2017 - (v4.1.8 - v4.2.7)
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association our data

we can load our data whenever we want.

ActiveRecord::Associations::Preloader.new.preload(@users, :company)
February 1, 2017 - (v4.1.8 - v4.2.7)
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Preload our own with out incude

we can preload our data whenever we want.

ActiveRecord::Associations::Preloader.new.preload(@users, :address)
January 24, 2017 - (v4.0.2 - v4.2.7)
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How to use belongs_to in Ruby on Rails

Rails 4: Let’s assume we have two models Movie and Actor. Actor has many movies and Movie belongs to Actor. In most of the cases, the developers used to validate the foreign key actor_id is present or not. In this case, it will not validate actor model as to whether the entered actor id exists or not. It is just like attribute validation which always validates that the fields should be non-empty when submitting the form.

Validation with foreign key:
class Movie < ApplicationRecord
belongs_to :actor
validates :actor_id, presence: true

class Movie < ApplicationRecord
belongs_to :actor
validates :actor_id, presence: true

class Actor < ApplicationRecord
has_many :movies, dependent: :destroy

class Actor < ApplicationRecord
has_many :movies, dependent: :destroy

The scenario above, validates actor id presence or not like normal attribute presence validator.

Ex: Actor.create(title:abc”).
=> {id: 1, title: 'abc'}
m = Movie.new(title:ok ok”, actor_id: 111)
=> m.valid? => true
=> Actor.find(111)
ActiveRecord::RecordNotFound: Couldn't find Actor with 'id'=111

Ex: Actor.create(title: “abc”).
=> {id: 1, title: 'abc'}
m = Movie.new(title: “ok ok”, actor_id: 111)
=> m.valid? => true
=> Actor.find(111)
ActiveRecord::RecordNotFound: Couldn't find Actor with  'id'=111

We can still save the movie record without valid actor.

With associations

class Movie < ApplicationRecord
belongs_to :actor
validates :actor, presence: true

class Movie < ApplicationRecord
belongs_to :actor
validates :actor, presence: true


class Movie < ApplicationRecord
belongs_to :actor, required: true

class Movie < ApplicationRecord
belongs_to :actor, required: true

class Actor < ApplicationRecord
has_many :movies, dependent: :destroy

class Actor < ApplicationRecord
has_many :movies, dependent: :destroy

Ex: Actor.create(title:abc”).
==> {id: 1, title: 'abc'}
m = Movie.new(title:ok ok”, actor_id: 111)
==> m.valid? => false
==> m.errors.full_messages, ['Actor can't be blank']

Ex: Actor.create(title:abc”).
==> {id: 1, title: 'abc'}
m = Movie.new(title:ok ok”, actor_id: 111)
==> m.valid? => false
==> m.errors.full_messages, ['Actor can't be blank']

In this case, it will always validate whether the entered actor exists or not. In case of an invalid actor it throws error to you. This is the best practise to make your associations. It always checks for the associated object exists or not.

Rails5 From rails5 these validations were added by default. It validates association object should be present when you define belongs_to associations.

Release notes http://guides.rubyonrails.org/5_0_release_notes.html(belongs_to will now trigger a validation error by default if the association is not present.)

We can opt out of this feature completely from the application by setting config opton in initializer file.



Rails.application.config.active_record.belongs_to_required_by_default = false Rails.application.config.active_record.belongs_to_required_by_default = false

This initializer file is present in rails5 application only. Need to add this initializer file manually when you migrate from older version of your rails application and make necessary changes.

class Post < ApplicationRecord
has_many :comments, dependent: :destroy	

class Post < ApplicationRecord
has_many :comments, dependent: :destroy	

class Comment < ApplicationRecord
belongs_to :post

class Comment < ApplicationRecord
belongs_to :post

c = Comment.create(title:awesome post”)
=>Post must exist”

c = Comment.create(title:awesome post”)
=>Post must exist”

We can not create any comment record without an associated record.

We can opt out this default behaviour by setting

belongs_to :post, optional: true
belongs_to :post, optional: true
c = Comment.create(title:awesome post”)
c = Comment.create(title:awesome post”)
=> <Comment id: 1, title:awesome post”, post_id: nil>


December 30, 2016
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Used within collection_check_boxes

Note the checked: option.

  = collection_check_boxes(:ahj_types, :ids, AhjType.order(:TypeName), :AHJTypeID, :TypeName) do |b|
      %td{style: 'padding: 0 1em;'}
        = b.label(class: "check_box")
      %td{style: 'padding: 0 1em;'}
        = b.check_box(class: "check_box", checked: (params[:ahj_types][:ids].member?(b.value.to_s)))
December 9, 2016
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dealing with semicolon

Use tag! method if you have semicolon, for example:

xml.tag!(“atom:link”, “href”=>“http://rubyplus.com/episodes.rss”, “rel”=>“self”, “type”=>“application/rss+xml”)

December 1, 2016
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November 28, 2016
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Track Changes To Your Model’s Data with Paper Trail Gem

Paper trail lets us track all the changes in the models data for the purpose of its editing and versioning. By using this gem, we can see how a model looks, at every stage of its life-cycle and we can take it back to any version of the model data and we can even undo all the changes after a record has been destroyed so as to restore it completely.

gempaper_trail’ run bundle install to install it

After bundle install you can run the following command for adding versions table to your database

bundle exec rails generate paper_trail:install

bundle exec rake db:migrate

Add has_paper_trail method to your models for tracking.

class Product < ActiveRecord::Base


If you are using a current_user method then you can track who is responsible for particular change by the below callback

class ApplicationController

before_action :set_paper_trail_whodunnit end

Features of paper trail gem

It stores each and every change happened in the model  like create, update and destroy
It does not store any updates unless if any modifications
It allows you to get every version including the actual and even once destroyed

Basic Usage

Now you have a versions method which returns all the changes in particular model

product = Product.find 2


# [<PaperTrail::Version>, <PaperTrail::Version>, ...]

Based on the vesrion you can find the changes that happened in a model

v = product.versions.last

   v.event # it returns update / create / destroy
   v.whodunnit #it returns a user id who did this
   v.reify the poduct as it was before the update

you can navigate versions by using previous_version and next_version methods

product = product.previous_version

   product = product.next_version #it returns nil if there is no object

   product.versions.last.whodunnit #it returns the user who did the particular change

For More Read From Here : http://www.railscarma.com/blog/technical-articles/track-changes-models-data-paper-trail-gem/

November 8, 2016
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Ways of Handling PayPal Refunds in Rails

PayPal Checkout includes payment solutions ranging from simple to robust that let the merchants as well as developers choose an integration option that can be the best-suited for their website and customers. In order to integrate Paypal Payment Gateway, we need to do the following:

  1. Have a PayPal business or Premier account.

  2. Create a PayPal app and get an access token. When we create a PayPal app, PayPal generates a set of OAuth client_id and secret keys for the application. PayPal generates these keys for both the PayPal sandbox and Live environments. To get an access token, pass the client-id:secret credentials in the Authorization header. We use the access token for authentication when we make REST API requests.

  3. To perform an end-to-end test of our Express Checkout with In-Context integration, create both merchant and buyer accounts in the PayPal sandbox environment.

www.sandbox.paypal.com/in/webapps/mpp/home Merchant : Select the Business account type and enter an email address and password. Buyer : Select the Personal account type and enter a high PayPal balance, such as 5000.

Once we create Paypal sandbox account then click on the “Profile” link for that account, look under the tab “API Credentials”. We will have the following information;

Paypal API Username
Paypal API Signature
Paypal API Password

Note: When we are ready to go live we would just use the credentials from our real paypal account instead of the ones from our sandbox account. The credentials can be found in the “My Profile” area under the left hand tab “My Selling Tools” under the option “API access”

How to handle Paypal refunds in Rails:

Method 1:

Paypal Rest API;

For more complex merchant sites, direct calls to PayPal APIs for an Express Checkout integration may be a more appropriate integration. REST APIs — We can develop an Express Checkout integration using PayPal REST APIs.

To integrate the Express Checkout with In-Context flow; developer.paypal.com/docs/api/ OR PayPal REST API Ruby SDK (paypal-sdk-rest gem): The PayPal REST SDK provides Ruby APIs to create, process and manage payment.

Installation: Add the gem our application, in Gemfile:

gem 'paypal-sdk-rest'

And then execute:

$ bundle install


rails g paypal:sdk:install

Refunds a transaction: Any transaction we can issue a refund (Both direct and captured payments):

Refund a completed direct payment (sale)
Refund an authorized and captured payment (capture)

Refund a completed payment (sale): If we must refund a completed payment, or sale, provide the sale id given to us in response to a completed payment along with an empty JSON payload for a full refund and for partial refunds, we can instead include an amount object in the JSON payload.

curl -v https://api.sandbox.paypal.com/v1/payments /sale/CARMAXYZC6136044L/refund \
-H "Content-Type:application/json" \
-H "Authorization: Bearer Access-Token" \
-d '{}'

Note: We should substitute all call-specific parameters, such as tokens and IDs, with our own. Response state of the refund:

pending- The refund is pending.
completed- The refund has successfully completed.
failed- The refund failed.

Refund a captured payment; We can also refund a captured payment: API:


Note: We must provide an amount object for both full and partial refunds.

curl -v https://api.sandbox.paypal.com/v1/payments/capture/CARMAXYZC6136044L/refund \
-H "Content-Type:application/json" \
-H "Authorization: Bearer Access-Token" \
-d '{
"currency": "USD",
"total": "50.54"
"description": "This is the capture refund description."

Reference: https://developer.paypal.com

Method 2:

Paypal refund by using Active Merchant Gem:

ActiveMerchant Integration: http://railscasts.com/episodes/145-integrating-active-merchant

In our Application;


config.after_initialize do

ActiveMerchant::Billing::Base.mode = :test
::GATEWAY = ActiveMerchant::Billing::PaypalGateway.new(
:login => "seller_1229899173_biz_api1.xyz.com",
:password => "FXWU58S7KXFC6HBE",
:signature =>AGjv6SW.mTiKxtkm6L9DcSUCUgePAUDQ3L- kTdszkPG8mRfjaRZDYtSu"



Refunds a transaction: Take a look into paypal_common_api.rb file in Active Merchant Gem;

  1. For a full refund pass nil for the amount:

gateway.refund nil, 'CARMAXYZC6136044L'

This will automatically make the :refund_type be “Full”.

  1. For a partial refund just pass the amount as usual:

gateway.refund 100, 'CARMAXYZC6136044L'
def refund(money, identification, options = {})
commit 'RefundTransaction', build_refund_request(money,  identification, options)


Gateway.refund(nil,'CARMAXYZC6136044L') => Full Refund.

Gateway.refund(798,'CARMAXYZC6136044L') => Partial Refund.

Reference: http://www.rubydoc.info/github/Shopify/active_merchant/ActiveMerchant/Billing/PaypalCommonAPI

Method3: Read More From Here==> http://www.railscarma.com/blog/technical-articles/ways-handling-paypal-refunds-rails/

October 27, 2016 - (<= v3.2.13)
1 thank

An example, with expiration time set


Rails.cache.fetch("out_of_stock_products", :expires_in => 5.minutes) do
  Product.all.joins(:inventory).conditions.where("inventory.quantity = 0")
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

October 3, 2016
0 thanks

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

September 23, 2016 - (<= 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 13, 2016 - (v3.2.1 - v4.2.7)
0 thanks

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/

September 1, 2016
0 thanks

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