Use futures to fetch all products in a page concurrently. With futures: ~5 seconds Without: ~ 32 seconds

concurrent_bootic_products.rb

require "open-uri"
require 'json'

def json(url)
  JSON.parse(open(url, 'Authorization' => 'Bearer API_TOKEN').read)
end

class Future < BasicObject
  def initialize(callable)
    @thread ||= ::Thread.new { callable.call }
  end

  def value
    @thread.value
  end

  def inspect
    if @thread.alive?
      "#<Future running>"
    else
      value.inspect
    end
  end

  def method_missing(method, *args)
    value.send(method, *args)
  end

  def respond_to_missing?(method, include_private = false)
    value.respond_to?(method, include_private)
  end
end

module Kernel
  def future(&block)
    Future.new(block)
  end
end

class Resource
  def initialize(url)
    @url = url
  end

  def links
    document['items'].map {|pr| pr['links']['self']['href']}
  end

  def title
    document['properties']['title']
  end
  
  def description
    document['properties']['description']
  end

  def get
    document
    self
  end

  private

  def document
    @document ||=json(@url)
  end
end

class Index

  def initialize(url)
    @resource = Resource.new(url)
  end

  def urls
    @resource.links
  end
end

class Crawler
  def initialize(index)
    @index = index
  end

  def crawl
    resources.each do |page|
      Outputter.new(page).output
    end
  end

  private

  def resources
    @index.urls.map do |url|
      future { Resource.new(url).get }
      # Resource.new(url).get
    end
  end
end

require "highline"

class Outputter
  OUTPUT_WIDTH = 79

  def initialize(page)
    @page = page
  end

  def output
    highline.say("-" * OUTPUT_WIDTH)
    highline.say(@page.title)
    highline.say("-" * OUTPUT_WIDTH)
    highline.say("\n\n")
  end

  private

  def highline
    @highline ||= HighLine.new($stdin, $stdout, OUTPUT_WIDTH)
  end
end

Crawler.new(Index.new("https://api.bootic.net/v1/products.json")).crawl