I. Shhopping Cart

1. Include models:

• Product: name, price, description, image
• Category: name
• Cart
• LineItem: quantity
• User: username, email, password

2. Set up association between models:

• Product:

belongs_to :category
has_many :line_items, dependent: :destroy
belongs_to :user, optional: true

• Category: has_many :products

• Cart: has_many :line_items, dependent: :destroy

• LineItem: belongs_to :product belongs_to :cart

• User: has_many :products

II. Use Elasticsearch to search product

1. Install Elasticsearch on MacOS

• Install JDK:

brew tap caskroom/versions
brew cask install java8

• Install elasticsearch: brew install elasticsearch

2. Run elasticsearch

• Use command: elasticsearch

• Navigate to http://127.0.0.1:9200/ on browser to see a json response like the one below:

{
  "name" : "mB8WtfU",
  "cluster_name" : "elasticsearch_letavi",
  "cluster_uuid" : "xKy9ZxAtSTOXBuEmq1Nbqg",
  "version" : {
    "number" : "6.6.1",
    "build_flavor" : "oss",
    "build_type" : "tar",
    "build_hash" : "1fd8f69",
    "build_date" : "2019-02-13T17:10:04.160291Z",
    "build_snapshot" : false,
    "lucene_version" : "7.6.0",
    "minimum_wire_compatibility_version" : "5.6.0",
    "minimum_index_compatibility_version" : "5.0.0"
  },
  "tagline" : "You Know, for Search"
}

3. Integrating Elasticsearch

• In Gemfile, add bellow gems:

gem 'elasticsearch-model'
gem 'elasticsearch-rails'

• Run bundle install to install gems
• Add SearchController with action search
• In search action define:

@roducts = params[:q].nil? ? [] : Product.search(params[:q])

Check if there is a query params if there isn't then show all products else show products that contains the query params.

• Integrating search into product: To add the ElasticSearch integration to the Product model, require elasticsearch/model and include the main module in Product class.

Modify app/models/product.rb to have the following content:

require 'elasticsearch/model'
class Product < ActiveRecord::Base
  include Elasticsearch::Model
  include Elasticsearch::Model::Callbacks
end
Product.import

Notes: If errors, change Product.import to Product.import(force: true)

In the code snippet above Product.import auto sync model with elastic search.

• Create a new file at app/views/search/search.html.erb
• Add a search route: Add the search route to config/routes.rb with the content: get 'search', to: 'search#search'