A Rails coding assignment that hits an external API and updates Product records based on a JSON payload.

telnyx_code_challenge.rb

require 'rubygems'
require 'sinatra'
require 'honeybadger'
require 'rest-client'

class App < Sinatra::Base
  # Basic POST route to update Product records via a fetch
  # to Omega Pricing's API
  post '/update_records/' do
    start_date = Date.today.prev_month.to_s
    end_date = Date.today.to_s

    product_records = get_product_records(start_date, end_date)

    product_records.each do |product_record|
      parse_external_product(product_record)
    end
  end
end

# Gets product records for a set amount of time
# @param [start_date] start of query interval
# @param [end_date] end of query interval
def get_product_records(start_date, end_date)
  api_key = ENV['OMEGA_PRICING_KEY'] # 'abc123key'
  api_url = ENV['OMEGA_PRICING_URL'] # 'https://omegapricinginc.com/pricing/records.json'

  url = URI.escape(api_url)
  api_params = {api_key: api_key, start_date: start_date, end_date: end_date} # Assuming the date format is "YYYY-MM-DD"
  response = RestClient.get(url, {params: api_params})
  
  if(response.status_code == 200)
    JSON.parse(response.body)
  else
    raise "Error making GET request to Omega Pricing's API."
  end
end

# Parses external Product records if conditions are met
# @param [external_product_record] json payload of product_record information
def parse_external_product(external_product_record)
  existing_product = Product.where(external_product_id: external_product_record['id']).first

  if existing_product.present?
    update_product(existing_product.id, external_product_record)
  elsif (discontinued = external_product_record['discontinued'])
    return
  elsif existing_product.empty? && !discontinued
    Product.create!(external_product_record) # Assuming that the Product initializer allows an external_product_record as a param
  else
    raise "Error while parsing external product record: #{external_product_record}."
  end
end

# Updates product price and creates a PastPriceRecord
# @param [product_id] ID for Product to be updated
# @param [external_product_record] json payload of product_record information
def update_product(product_id, external_product_record)
  return unless (product = Product.find(product_id)).present? && (new_price = external_product_record['price']).present?

  if product.name != external_product_record['name']
    raise "Name mismatch for Product ##{product_id}: was expecting #{product.name} but got got #{external_product_record['name']}."
  else
    ActiveRecord::Base.transaction do 
      percentage_change = product.price / new_price # Assuming new_price is >= 0

      product.update!({price: new_price})
      product.past_price_records.build!(price: new_price, percentage_change: percentage_change) # Assuming this method exists; Rails convention
    end
  end
end