Ruby on Rails Purchase item from Amazon using API?

Question

I'd like to programmatically automate making a purchase on Amazon from my rails app as I have to manually make the same purchases week after week. This would be using my own billing information/account, not on behalf of a user.

I've searched through most of their APIs and found that you can search for an item, add it to a cart, etc. but I can't seem to find a way to actually make the purchase.

Does anyone know of a way to do this via API? It'd be great automate our manual process. It seems like it should be possible as https://zincapi.com/ seems to facilitate this.

Answer 1

You can do this, just not via the API. Instead, use:

Mechanize

As neatly described in their docs:

The Mechanize library is used for automating interaction with websites. Mechanize automatically stores and sends cookies, follows redirects, and can follow links and submit forms. Form fields can be populated and submitted.

You can program an advanced web crawler which

• logs you into Amazon
• adds your desired item to the basket
• checks out and pays your desired items

How to set this up

I will suggest some logic and describe the process roughly. It would be beyond the scope of the question to explain everything in detail. Be prepared for a lot of digging.

1. Add your Crawler

Dig right into Mechanize. Learn how to login to your site, search for links, press buttons and all that neat stuff. It is built upon Nokogiri which uses CSS selectors. It may take a while to grasp, but it is worth the sweat!

Also, split up the logic of the single tasks into different methods. Something like

class AmazonCrawler
  attr_accessor :agent

  def initialize
    @agent = Mechanize.new
  end

  def login
    agent.get(LOGIN_PATH)
    # fill in and submit the form
  end

  def add_item_to_basket
    agent.get(ITEM_PATH)
    # find 'add to basket', etc...
  end

  def checkout
    agent.get(CHECKOUT_PATH)
    # validate adress, payment and place the order
  end

  def place_weekly_order
    AmazonCrawler.login
    AmazonCrawler.add_item_to_basket
    AmazonCrawler.checkout
  end
end

This way, you can easily add other tasks if you may need them later

2. Add a Cronjob

To setup your weekly schedule, I'd suggest using the whenever gem. This gem makes scheduling tasks easy peasy

schedule.rb

every :sunday, :at => '12pm' do
  runner "AmazonCrawler.place_weekly_order"
end

Sidenote

Ideally I would set up a specific Amazon account that only does that. You would not want the bot to checkout items which you personally have added during the week and may not be certain about purchasing yet.

Also, be sure to store your credentials in ENV variables, so they are not exposed in your code.

Conclusion

I hope this gets you going, there will be a lot of new stuff for you to learn, but it actually is a fun task and will be very rewarding when your little crawler is up and running.