Getting started for Ruby developers

Directed Edge makes integrating with our recommendations engine easy with Ruby. We provide bindings that handle all of the communication with our server transparently using normal Ruby objects.

Getting started

• Introduction to Recommendations is a good starting point if you're wondering how recommendations work or what they're useful for.
• API Concepts explains some of the basics of hour our API works and introduces the concepts of items, tags and links, also explained briefly below.
• Grab the Ruby bindings from GitHub and copy the file named Ruby/directed_edge.rb into your project. You'll need to make sure you have rubygems and the rest_client Gem installed. Alternatively, you can install our Gem directly with sudo gem install directed-edge.

Data modeling

Items and links

To model the data from your site, you'll need to figure out what your items are. Usually they're things like users, products and articles. We represent a relationship between items by links. So, if you have Bob Dylan's "Blonde on Blonde" that you want to say was bought by "John Doe", you create a link from "John Doe" to "Blonde on Blonde".

Identifiers

Usually we don't need to actually know the names of those items — they just need a unique identifier. Typically that's something like customer1 and product1. Most people just use the ID field from their own database. So if you have a MySQL table named products and Blonde on Blonde is at the row with ID 42 then you'd just use product42 as your identifier for that product.

Tags

Items also have tags, so John Doe would probably have a user tag and Blonde on Blonde would have a product tag. Tags don't weigh into the ranking at all — they're just used so that you can filter the sort of results you'd like to get. So if you want to show related products, you'd run a query looking for things with the tag product.

Querying for recommendations

We offer two primary sorts of recommendations, called related and recommended:

Related is for example if you have one product and you want to find similar products, or a user and want to find similar users. To find products related to Blonde on Blonde you'd send a related query for that item, looking for things tagged product.

Recommended is for doing personalized recommendations, e.g. Products Bob is likely to be interested in... To do a recommended query, you would send a request for the item that corresponds to Bob looking for things that are tagged product.

API Documentation

You can find full documentation for the bindings classes here.

Tutorial

• Ruby Bindings for E-Commerce Tutorial provides a detailed step-by-step walkthrough of how to get up and going with a store — it's based on the same code as below, but with lots of details.

Example

ExampleStore is an example of how you'd connect a store with customers, products and purchases to our recommendations engine, including exporting data and querying the web services.

#!/usr/bin/ruby

require 'rubygems'
require 'activerecord'
require 'directed_edge'

ActiveRecord::Base.establish_connection(:adapter => 'mysql',
                                        :host => 'localhost',
                                        :username => 'examplestore',
                                        :password => 'password',
                                        :database => 'examplestore')

class Customer < ActiveRecord::Base
end

class Product < ActiveRecord::Base
end

class Purchase < ActiveRecord::Base
end

class ExampleStore
  def initialize
    @database = DirectedEdge::Database.new('examplestore', 'password')
  end

  def export_from_mysql
    exporter = DirectedEdge::Exporter.new('examplestore.xml')

    Customer.find(:all).each do |customer|
      item = DirectedEdge::Item.new(exporter.database, "customer#{customer.id}")
      item.add_tag('customer')
      purchases = Purchase.find(:all, :conditions => { :customer => customer.id })
      purchases.each { |purchase| item.link_to("product#{purchase.product}") }
      exporter.export(item)
    end

    Product.find(:all).each do |product|
      item = DirectedEdge::Item.new(exporter.database, "product#{product.id}")
      item.add_tag('product')
      exporter.export(item)
    end

    exporter.finish
  end

  def import_to_directededge
    @database.import('examplestore.xml')
  end

  def create_customer(id)
    item = DirectedEdge::Item.new(@database, "customer#{id}")
    item.add_tag('customer')
    item.save
  end

  def create_product(id)
    item = DirectedEdge::Item.new(@database, "product#{id}")
    item.add_tag('product')
    item.save
  end

  def add_purchase(customer_id, product_id)
    item = DirectedEdge::Item.new(@database, "customer#{customer_id}")
    item.link_to("product#{product_id}")
    item.save
  end

  def related_products(product_id)
    item = DirectedEdge::Item.new(@database, "product#{product_id}")
    item.related(['product']).map { |product| product.sub('product', '').to_i }
  end

  def personalized_recommendations(customer_id)
    item = DirectedEdge::Item.new(@database, "customer#{customer_id}")
    item.recommended(['product']).map { |product| product.sub('product', '').to_i }
  end
end

store = ExampleStore.new

store.export_from_mysql
store.import_to_directededge

store.create_customer(500)
store.create_product(2000)
store.add_purchase(500, 2000)

store.related_products(1).each do |product|
  puts "Related products for product 1: #{product}"
end

store.personalized_recommendations(1).each do |product|
  puts "Personalized recommendations for user 1: #{product}"
end

Further Reading

If you want to dig deeper into how the web services work — the REST API, XML Format and Web Services Examples articles explain what's going on behind the scenes when you use our bindings.