From 2d0df99e34d447431454a13cd5492ba056b58827 Mon Sep 17 00:00:00 2001
From: Mike Shaw <44751023+mikeshaw-stripe@users.noreply.github.com>
Date: Wed, 3 Apr 2019 12:29:17 +0100
Subject: [PATCH] Add Ruby Sinatra server (#54)

* Adding a ruby backend

* Updating README

* Fix shipping_change endpoint.

* Fixing nits, README and removing API Version hack

* Load skus separately.

* Update main README.
---
 README.md                   |   8 +-
 public/javascripts/store.js |  19 ++-
 server/ruby/GemFile         |   8 ++
 server/ruby/Gemfile.lock    |  54 +++++++++
 server/ruby/README.md       |  64 ++++++++++
 server/ruby/app.rb          | 226 ++++++++++++++++++++++++++++++++++++
 server/ruby/inventory.rb    |  50 ++++++++
 server/ruby/setup.rb        |  84 ++++++++++++++
 8 files changed, 511 insertions(+), 2 deletions(-)
 create mode 100644 server/ruby/GemFile
 create mode 100644 server/ruby/Gemfile.lock
 create mode 100644 server/ruby/README.md
 create mode 100644 server/ruby/app.rb
 create mode 100644 server/ruby/inventory.rb
 create mode 100644 server/ruby/setup.rb

diff --git a/README.md b/README.md
index a1d9a323..20641e0c 100644
--- a/README.md
+++ b/README.md
@@ -61,7 +61,13 @@ The [Sources API](https://stripe.com/docs/sources) provides a single integration
 
 ## Getting Started with Node
 
-There are a couple server implementations in the [`server`](/server) directory. Instructions for running the Node.js server in [`server/node`](/server/node) are below, but if you’re more comfortable with Python you can find a README explaining how to run a Flask server in the [`server/python`](/server/python) directory. Both servers have the same endpoints to handle requests from the frontend and interact with the [Stripe libraries](https://stripe.com/docs/libraries).
+Instructions for running the Node.js server in [`server/node`](/server/node) are below. You can find alternative server implementations in the [`server`](/server) directory:
+
+- Node, Express: [`server/node`](/server/node)
+- Python, Flask: [`server/python`](/server/python)
+- Ruby, Sinatra: [`server/ruby`](/server/ruby)
+
+All servers have the same endpoints to handle requests from the frontend and interact with the [Stripe libraries](https://stripe.com/docs/libraries).
 
 ### Requirements
 
diff --git a/public/javascripts/store.js b/public/javascripts/store.js
index 54f98a7f..a548e93e 100644
--- a/public/javascripts/store.js
+++ b/public/javascripts/store.js
@@ -54,13 +54,30 @@ class Store {
     }
   }
 
+  // Retrieve a SKU for the Product where the API Version is newer and doesn't include them on v1/product
+  async loadSkus(product_id) {
+    try {
+      const response = await fetch(`/product/${product_id}/skus`);
+      const skus = await response.json();
+      this.products[product_id].skus = skus;
+    } catch (err) {
+      return {error: err.message};
+    }
+  }
+
   // Load the product details.
   loadProducts() {
     if (!this.productsFetchPromise) {
       this.productsFetchPromise = new Promise(async resolve => {
         const productsResponse = await fetch('/products');
         const products = (await productsResponse.json()).data;
-        products.forEach(product => (this.products[product.id] = product));
+        // Check if we have SKUs on the product, otherwise load them separately.
+        for (const product of products) {
+          this.products[product.id] = product;
+          if (!product.skus) {
+            await this.loadSkus(product.id);
+          }
+        }
         resolve();
       });
     }
diff --git a/server/ruby/GemFile b/server/ruby/GemFile
new file mode 100644
index 00000000..0d567064
--- /dev/null
+++ b/server/ruby/GemFile
@@ -0,0 +1,8 @@
+source 'https://rubygems.org/'
+
+gem 'sinatra'
+gem 'sinatra-reloader'
+gem 'stripe'
+gem 'dotenv'
+gem 'json'
+gem 'ruby-debug-ide'
diff --git a/server/ruby/Gemfile.lock b/server/ruby/Gemfile.lock
new file mode 100644
index 00000000..4ca9b117
--- /dev/null
+++ b/server/ruby/Gemfile.lock
@@ -0,0 +1,54 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    backports (3.12.0)
+    connection_pool (2.2.2)
+    dotenv (2.7.1)
+    faraday (0.15.4)
+      multipart-post (>= 1.2, < 3)
+    json (2.2.0)
+    multi_json (1.13.1)
+    multipart-post (2.0.0)
+    mustermann (1.0.3)
+    net-http-persistent (3.0.0)
+      connection_pool (~> 2.2)
+    rack (2.0.6)
+    rack-protection (2.0.5)
+      rack
+    rake (12.3.2)
+    ruby-debug-ide (0.6.1)
+      rake (>= 0.8.1)
+    sinatra (2.0.5)
+      mustermann (~> 1.0)
+      rack (~> 2.0)
+      rack-protection (= 2.0.5)
+      tilt (~> 2.0)
+    sinatra-contrib (2.0.5)
+      backports (>= 2.8.2)
+      multi_json
+      mustermann (~> 1.0)
+      rack-protection (= 2.0.5)
+      sinatra (= 2.0.5)
+      tilt (>= 1.3, < 3)
+    sinatra-reloader (1.0)
+      sinatra-contrib
+    sorbet (0.0.1.pre.prealpha)
+    stripe (4.9.0)
+      faraday (~> 0.13)
+      net-http-persistent (~> 3.0)
+    tilt (2.0.9)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  dotenv
+  json
+  ruby-debug-ide
+  sinatra
+  sinatra-reloader
+  sorbet (~> 0.0.1.pre.prealpha)
+  stripe
+
+BUNDLED WITH
+   2.0.1
diff --git a/server/ruby/README.md b/server/ruby/README.md
new file mode 100644
index 00000000..9cebc584
--- /dev/null
+++ b/server/ruby/README.md
@@ -0,0 +1,64 @@
+# Stripe Payments Demo - Ruby Server
+
+This demo uses a simple [Sinatra](http://sinatrarb.com/) application as the server.
+
+## Payments Integration
+
+- [`app.rb`](app.rb) contains the routes that interface with Stripe to create charges and receive webhook events.
+- [`setup.rb`](setup.rb) a simple setup script to make some fake Products and SKUs for our Stripe store.
+- [`inventory.rb`](inventory.rb) a minimal wrapper over the Stripe Python SDK that handles creating/fetching products and caluclating payment amounts from SKUs. You can override this class with your own product and order management system code.
+
+## Requirements
+
+You’ll new the following:
+
+- [Ruby 2.X](https://www.ruby-lang.org/en/downloads/)
+- Modern browser that supports ES6 (Chrome to see the Payment Request, and Safari to see Apple Pay).
+- Stripe account to accept payments ([sign up](https://dashboard.stripe.com/register) for free!)
+
+## Getting Started
+
+Before getting started check that you have ruby installed
+
+```
+ruby --version
+```
+
+Copy the example environment variables file `.env.example` from the root of the repo into your own environment file called `.env`:
+
+```
+cp .env.example .env
+```
+
+User `bundler` to install the required gems by navigating to ./server/ruby and running:
+
+```
+bundle install
+```
+
+Run the Sinatra application
+
+```
+bundle exec ruby app.rb
+```
+
+You should now see it running on [`http://localhost:4567/`](http://localhost:4567/)
+
+### Testing Webhooks
+
+If you want to test [receiving webhooks](https://stripe.com/docs/webhooks), we recommend using ngrok to expose your local server.
+
+First [download ngrok](https://ngrok.com) and start your Sinatra application.
+
+[Run ngrok](https://ngrok.com/docs). Assuming your Sinatra application is running on the default port 4567, you can simply run ngrok in your Terminal in the directory where you downloaded ngrok:
+
+```
+ngrok http 4567
+```
+
+ngrok will display a UI in your terminal telling you the new forwarding address for your Sinatra app. Use this URL as the URL to be called in your developer [webhooks panel.](https://dashboard.stripe.com/account/webhooks)
+
+Don't forget to append `/webhook` when you set up your Stripe webhook URL in the Dashboard. Example URL to be called: `https://75795038.ngrok.io/webhook`.
+
+## Credits
+- Code: [Mike Shaw](https://www.linkedin.com/in/mandshaw/)
\ No newline at end of file
diff --git a/server/ruby/app.rb b/server/ruby/app.rb
new file mode 100644
index 00000000..4e8dc6ff
--- /dev/null
+++ b/server/ruby/app.rb
@@ -0,0 +1,226 @@
+require 'stripe'
+require 'sinatra'
+require 'sinatra/cookies'
+# require 'sinatra/reloader'
+require 'dotenv'
+require 'json'
+require_relative 'inventory'
+require_relative 'setup'
+
+Dotenv.load(File.dirname(__FILE__) + '/../../.env')
+Stripe.api_key = ENV['STRIPE_SECRET_KEY']
+Stripe.api_version = '2019-02-11'
+
+set :static, true
+set :root, File.dirname(__FILE__)
+set :public_folder, Dir.chdir(Dir.pwd + '/../../public')
+
+
+get '/javascripts/:path' do
+  content_type 'text/javascript'
+  send_file "javascripts/#{params['path']}"
+end
+
+get '/stylesheets/:path' do
+  content_type 'text/css'
+  send_file "stylesheets/#{params['path']}"
+end
+
+get '/images/*.*' do |path, ext|
+  if ext == "svg"
+    content_type "image/#{ext}+xml"
+  else
+    content_type "image/#{ext}"
+  end
+  send_file "images/#{path}.#{ext}"
+end
+
+get '/' do
+  # Route to the index page which will show our cart 
+  content_type 'text/html'
+  send_file 'index.html'
+end
+
+get '/config' do
+  # Route to return configurations details required by the frontend
+  content_type 'application/json'
+  {
+    'stripePublishableKey': ENV['STRIPE_PUBLISHABLE_KEY'],
+    'stripeCountry': ENV['STRIPE_ACCOUNT_COUNTRY'] || 'US',
+    'country': 'US',
+    'currency': 'eur',
+    'paymentMethods': ENV['PAYMENT_METHODS'] ? ENV['PAYMENT_METHODS'].split(', ') : ['card'],
+    'shippingOptions': [
+      {
+        'id': 'free',
+        'label': 'Free Shipping',
+      'detail': 'Delivery within 5 days',
+        'amount': 0,
+      },
+      {
+        'id': 'express',
+          'label': 'Express Shipping',
+          'detail': 'Next day delivery',
+          'amount': 500,
+      }
+    ]
+  }.to_json
+end
+
+get '/products' do
+  content_type 'application/json'
+  products = Inventory.list_products
+  if Inventory.products_exist(products)
+    products.to_json
+  else
+    # Setup products
+    puts "Needs to setup products"
+    create_data
+    products = Inventory.list_products
+    products.to_json
+  end
+end
+
+get '/product/:product_id/skus' do
+  content_type 'application/json'
+  skus = Inventory.list_skus(params['product_id'])
+  skus.to_json
+end
+
+get '/products/:product_id' do
+  content_type 'application/json'
+  product = Inventory.retrieve_product(params['product_id'])
+  product.to_json
+end
+
+post '/payment_intents' do
+  content_type 'application/json'
+  data = JSON.parse request.body.read
+
+  payment_intent = Stripe::PaymentIntent.create(
+    amount: Inventory.calculate_payment_amount(data['items']),
+    currency: data['currency'],
+    payment_method_types: ENV['PAYMENT_METHODS'] ? ENV['PAYMENT_METHODS'].split(', ') : ['card']
+  )
+
+  {
+    paymentIntent: payment_intent
+  }.to_json
+end
+
+post '/payment_intents/:id/shipping_change' do
+  content_type 'application/json'
+  data = JSON.parse request.body.read
+
+  amount = Inventory.calculate_payment_amount(data['items'])
+  amount += Inventory.get_shipping_cost(data['shippingOption']['id'])
+
+  payment_intent = Stripe::PaymentIntent.update(
+    params['id'],
+    {
+      amount: amount
+    }
+  )
+  
+  {
+    paymentIntent: payment_intent
+  }.to_json
+end
+
+post '/webhook' do
+  # You can use webhooks to receive information about asynchronous payment events.
+  # For more about our webhook events check out https://stripe.com/docs/webhooks.
+  webhook_secret = ENV['STRIP_WEBHOOK_SECRET']
+  request_data = JSON.parse request.body.read
+
+  if webhook_secret
+    # Retrieve the event by verifying the signature using the raw body and secret if webhook signing is configured.
+    sig_header = request.env['HTTP_STRIPE_SIGNATURE']
+
+    begin
+      event = Stripe::Webhook.construct_event(
+          payload, sig_header, endpoint_secret
+      )
+    rescue JSON::ParserError => e
+        # Invalid payload
+        status 400
+        return
+    rescue Stripe::SignatureVerificationError => e
+        # Invalid signature
+        status 400
+        return
+    end
+    # Get the type of webhook event sent - used to check the status of PaymentIntents.    
+    event_type = event['type']
+  else
+    data = request_data['data']
+    event_type = request_data['type']
+  end
+
+  data_object = data['object']
+
+  # PaymentIntent Beta, see https://stripe.com/docs/payments/payment-intents
+  # Monitor payment_intent.succeeded & payment_intent.payment_failed events.
+  if data_object['object'] == 'payment_intent'
+    payment_intent = data_object
+
+    if event_type == 'payment_intent.succeeded'
+      puts "🔔  Webhook received! Payment for PaymentIntent #{payment_intent['id']} succeeded"
+    elsif event_type == 'payment_intent.payment_failed'
+      puts "🔔  Webhook received! Payment on source #{payment_intent['last_payment_error']['source']['id']} for PaymentIntent #{payment_intent['id']} failed."
+    end
+
+  # Monitor `source.chargeable` events.
+  elsif data_object['object'] == 'source' && data_object['status'] == 'chargeable' && data_object['metadata'].include?('paymentIntent')
+    source = data_object
+    puts "🔔  Webhook received! The source #{source['id']} is chargeable"
+
+    # Find the corresponding PaymentIntent this Source is for by looking in its metadata.
+    payment_intent = Stripe::PaymentIntent.retrieve(
+      source['metadata']['paymentIntent']
+    )
+
+    # Verify that this PaymentIntent actually needs to be paid.
+    if payment_intent['status'] != 'requires_payment_method'
+      status 403
+      {
+        error: "PaymentIntent already has a status of #{payment_intent['status']}"
+      }.to_json
+    end
+
+    # Confirm the PaymentIntent with the chargeable source.
+    payment_intent.confirm(
+      {
+        source: source['id']
+      }
+    )
+  
+  # Monitor `source.failed` and `source.canceled` events.  
+  elsif data_object['object'] == 'source' && ['failed', 'canceled'].include?(data_object['status'])
+    # Cancel the PaymentIntent.
+    source = data_object
+    intent = Stripe::PaymentIntent.retrieve(
+      source['metadata']['paymentIntent']
+    )
+    intent.cancel
+  end
+
+  content_type 'application/json'
+  {
+    status: 'success'
+  }.to_json
+
+end
+
+get '/payment_intents/:id/status' do
+  payment_intent = Stripe::PaymentIntent.retrieve(
+    params['id']
+  )
+
+  content_type 'application/json'
+  {
+    paymentIntent: {
+      status: payment_intent['status']
+    }
+  }.to_json
+end
\ No newline at end of file
diff --git a/server/ruby/inventory.rb b/server/ruby/inventory.rb
new file mode 100644
index 00000000..c07b6cec
--- /dev/null
+++ b/server/ruby/inventory.rb
@@ -0,0 +1,50 @@
+require 'stripe'
+require 'dotenv'
+
+Dotenv.load(File.dirname(__FILE__) + '/../../.env')
+
+Stripe.api_key = ENV['STRIPE_SECRET_KEY']
+Stripe.api_version = '2019-02-11'
+
+class Inventory
+
+  def self.calculate_payment_amount(items)
+    total = 0
+    items.each do |item|
+      sku = Stripe::SKU.retrieve(item['parent'])
+      total += sku.price * item['quantity']
+    end
+    total
+  end
+
+  def self.get_shipping_cost(id)
+    shipping_cost = {
+      free: 0,
+      express: 500,
+    }
+    shipping_cost[id.to_sym]
+  end
+
+  def self.list_products
+    Stripe::Product.list(limit: 3)
+  end
+
+  def self.list_skus(product_id)
+    Stripe::SKU.list(
+      limit: 1,
+      product: product_id
+      )
+  end
+
+  def self.retrieve_product(product_id)
+    Stripe::Product.retrieve(product_id)
+  end
+
+  def self.products_exist(product_list)
+    valid_products = ['increment', 'shirt', 'pins']
+    product_list_data = product_list['data']
+    products_present = product_list_data.map {|product| product['id']}
+
+    product_list_data.length == 3 && products_present & valid_products == products_present
+  end
+end
\ No newline at end of file
diff --git a/server/ruby/setup.rb b/server/ruby/setup.rb
new file mode 100644
index 00000000..d3f41fb4
--- /dev/null
+++ b/server/ruby/setup.rb
@@ -0,0 +1,84 @@
+require 'stripe'
+require 'dotenv'
+
+Dotenv.load(File.dirname(__FILE__) + '/../../.env')
+
+Stripe.api_key = ENV['STRIPE_SECRET_KEY']
+Stripe.api_version = '2019-02-11'
+
+def create_data
+  begin
+    products = [
+      {
+        id: 'increment',
+        type: 'good',
+        name: 'Increment Magazine',
+        attributes: ['issue']
+      },
+      {
+        id: 'pins',
+        type: 'good',
+        name: 'Stripe Pins',
+        attributes: ['set']
+      },
+      {
+        id: 'shirt',
+        type: 'good',
+        name: 'Stripe Shirt',
+        attributes: ['size', 'gender']
+      }
+    ]
+
+    products.each do |product|
+      Stripe::Product.create(product)
+    end
+
+    skus = [
+      {
+        id: 'increment-03',
+        product: 'increment',
+        attributes: {
+          issue: 'Issue #3 “Development”'
+        },
+        price: 399,
+        currency: 'usd',
+        inventory: {
+          type: 'infinite'
+        }
+      },
+      {
+        id: 'shirt-small-woman',
+        product: 'shirt',
+        attributes: {
+          size: 'Small Standard',
+          gender: 'Woman'
+        },
+        price: 999,
+        currency: 'usd',
+        inventory: {
+          type: 'infinite'
+        }
+      },
+      {
+        id: 'pins-collector',
+        product: 'pins',
+        attributes: {
+          set: 'Collector Set'
+        },
+        price: 799,
+        currency: 'usd',
+        inventory: {
+          type: 'finite',
+          quantity: 500
+        }
+      }
+    ]
+
+    skus.each do |sku|
+      Stripe::SKU.create(sku)
+    end
+
+  rescue Stripe::InvalidRequestError => e
+    puts "Products already exist, #{e}"
+  end
+end
\ No newline at end of file