MVP implementation that can complete a checkout

.rubocop.yml

@@ -9,3 +9,28 @@ AllCops:
     - dummy-app/**/*
     - spec/dummy/**/*
     - vendor/bundle/**/*
+
+# Avoiding the nested namespaces can avoid some
+# ambiguities, forcing full references.
+# Also saves horizontal space.
+Style/ClassAndModuleChildren:
+  Enabled: false
+
+# Gain space by indenting from the start of the line,
+# instead of the end of the method name.
+Layout/MultilineMethodCallIndentation:
+  EnforcedStyle: indented
+
+# More is more.
+RSpec/MultipleExpectations:
+  Enabled: false
+
+# This was suggesting to use the dangling comma instead,
+# which is super cryptic 🙈.
+Style/TrailingUnderscoreVariable:
+  Enabled: false
+
+# System specs aren't describing any specific class/module.
+RSpec/DescribeClass:
+  Exclude:
+    - spec/system/**/*

Gemfile

@@ -4,5 +4,9 @@ source 'https://rubygems.org'
 
 gemspec
 
+# Those are due to the "stdlib gemification" that's
+# happening between versions of ruby.
 gem 'stringio'
 gem 'timeout'
+
+gem 'listen'

Procfile.dev

@@ -0,0 +1,2 @@
+web: unset PORT && bin/rails-sandbox server
+installer: bin/rails-sandbox g solidus_stripe:install --force --watch

README.md

@@ -43,6 +43,16 @@ bin/rails generate solidus_stripe:install
 
 ## Development
 
+Retrieve your API Key and Publishable Key from your [Stripe testing dashboard](https://stripe.com/docs/testing).
+
+Set `SOLIDUS_STRIPE_API_KEY` and `SOLIDUS_STRIPE_PUBLISHABLE_KEY` environment variables (e.g. via `direnv`), this
+will trigger the default initializer to create a static preference for SolidusStripe.
+
+Run `bin/dev` to start both the sandbox rail server and the file watcher that will update the sandbox whenever
+a file is changed.
+
+Visit `/admin/payments` and create a new Stripe payment using the static preferences.
+
 ### Testing the extension
 
 First bundle your dependencies, then run `bin/rake`. `bin/rake` will default to building the dummy

app/controllers/solidus_stripe/payment_intents_controller.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require 'stripe'
+
+class SolidusStripe::PaymentIntentsController < Spree::BaseController
+  include Spree::Core::ControllerHelpers::Order
+
+  def create
+    payment_method = current_order(create_order_if_necessary: true)
+      .available_payment_methods.find(params[:payment_method_id])
+
+    currency = current_order.currency
+    amount = SolidusStripe::Gateway::MoneyToStripeAmountConverter.to_stripe_amount(
+      current_order.display_total.money.fractional,
+      currency,
+    )
+
+    intent, _response = payment_method.gateway.client.request do
+      Stripe::PaymentIntent.create({
+        amount: amount,
+        currency: currency,
+        capture_method: 'manual',
+      })
+    end
+
+    # TODO: send the payment source information to the frontend so
+    # it can be used for the payment step form.
+    _payment_source = SolidusStripe::PaymentSource.create!(
+      stripe_payment_intent_id: intent.id,
+      payment_method: payment_method,
+    )
+
+    render json: { client_secret: intent.client_secret }
+  end
+end

app/models/solidus_stripe.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module SolidusStripe
+  def self.table_name_prefix
+    "solidus_stripe_"
+  end
+end

app/models/solidus_stripe/gateway.rb

@@ -2,7 +2,9 @@
 
 require 'stripe'
 
-# rubocop:disable Lint/UnusedMethodArgument, Style/MethodCallWithoutArgsParentheses
+# Documentation about separate authorization and capture
+# - https://stripe.com/docs/payments/accept-a-payment?platform=web&ui=checkout#auth-and-capture
+# - https://stripe.com/docs/charges/placing-a-hold
 module SolidusStripe
   class Gateway
     def initialize(options)
@@ -13,31 +15,127 @@ def initialize(options)
       @options = options
     end
 
+    attr_reader :client
+
     # Authorizes a certain amount on the provided payment source.
-    def authorize(money, source, options = {})
-      ActiveMerchant::Billing::Response.new()
+    #
+    # @see #purchase
+    def authorize(amount_in_cents, source, options = {})
+      payment_intent_options = options[:payment_intent_options].dup.to_h
+      payment_intent_options[:capture_method] = "manual"
+      purchase(amount_in_cents, source, options.merge(payment_intent_options: payment_intent_options))
     end
 
     # Captures a certain amount from a previously authorized transaction.
-    def capture(money, transaction_id, options = {})
-      ActiveMerchant::Billing::Response.new()
+    # Ref: https://stripe.com/docs/api/payment_intents/capture#capture_payment_intent
+    # Ref: https://stripe.com/docs/payments/capture-later
+    #
+    # @todo add support for capturing custom amounts
+    #
+    # @param _amount_in_cents [Integer] The fractional amount as defined by Spree::Money,
+    #   although it's cents for most currencies some will have a different multiplier.
+    #   Currently ignored (see "todo" section).
+    # @param _transaction_id [Object] (currently ignored)
+    # @param options [Hash]
+    # @option options [Spree::Payment] :originator the payment on which the #capture is being performed (required)
+    #
+    # @return ActiveMerchant::Billing::Response
+    def capture(_amount_in_cents, _transaction_id, options = {})
+      payment = options[:originator] or raise ArgumentError, "please provide a payment with the :originator option"
+      payment_intent_id = payment.source.stripe_payment_intent_id
+
+      raise ArgumentError, "missing transaction_id" unless payment_intent_id
+
+      unless payment_intent_id.start_with?('pi_')
+        raise ArgumentError, "the payment-intent id has the wrong format"
+      end
+
+      payment_intent, _response = client.request { Stripe::PaymentIntent.capture(payment_intent_id) }
+
+      ActiveMerchant::Billing::Response.new(
+        true, "Capture was successful", { 'stripe_payment_intent' => payment_intent.to_json }, {}
+      )
+    rescue Stripe::InvalidRequestError => e
+      ActiveMerchant::Billing::Response.new(
+        false, e.to_s, { 'json_response' => e.response.to_json }, {}
+      )
     end
 
     # Authorizes and captures a certain amount on the provided payment source.
-    def purchase(money, source, options = {})
-      ActiveMerchant::Billing::Response.new()
+    #
+    # @param amount_in_cents [Integer] The fractional amount as defined by Spree::Money,
+    #   although it's cents for most currencies some will have a different multiplier.
+    # @param source [Spree::PaymentSource, nil] optionally, payment source from which to create the authorization
+    # @param options [Hash]
+    # @option options [Hash] :payment_intent_options options forwarded to `Stripe::PaymentIntent.create`
+    #
+    # @return ActiveMerchant::Billing::Response
+    def purchase(amount_in_cents, _source, options = {})
+      currency = options.fetch(:currency)
+
+      # Charge the Customer instead of the card:
+      payment_intent, _response = client.request do
+        Stripe::PaymentIntent.create({
+          amount: MoneyToStripeAmountConverter.to_stripe_amount(amount_in_cents, currency),
+          currency: currency,
+          **options[:payment_intent_options].to_h
+        })
+      end
+
+      ActiveMerchant::Billing::Response.new(
+        true, "PaymentIntent was created successfully", { 'stripe_payment_intent' => payment_intent.to_json }, {}
+      )
     end
 
     # Voids a previously authorized transaction, releasing the funds that are on hold.
     # The source parameter is only needed for payment gateways that support payment profiles.
-    def void(transaction_id, source, options = {})
-      ActiveMerchant::Billing::Response.new()
+    #
+    # @param _transaction_id [Object] (currently ignored)
+    # @param source [Spree::PaymentSource, nil] optionally, payment source from which to create the authorization
+    # @param _options [Hash] (ignored)
+    #
+    # @return ActiveMerchant::Billing::Response
+    def void(_transaction_id, source, _options = {})
+      payment_intent, _response = client.request do
+        Stripe::PaymentIntent.cancel(source.stripe_payment_intent_id)
+      end
+
+      ActiveMerchant::Billing::Response.new(
+        true, "PaymentIntent was canceled successfully", { 'stripe_payment_intent' => payment_intent.to_json }, {}
+      )
+    rescue Stripe::InvalidRequestError => e
+      ActiveMerchant::Billing::Response.new(
+        false, e.to_s, { 'json_response' => e.response.to_json }, {}
+      )
     end
 
     # Refunds the provided amount on a previously captured transaction.
     # The source parameter is only needed for payment gateways that support payment profiles.
-    def credit(money, source, transaction_id, options = {})
-      ActiveMerchant::Billing::Response.new()
+    #
+    # @param amount_in_cents [Integer] The fractional amount as defined by Spree::Money,
+    #   although it's cents for most currencies some will have a different multiplier.
+    # @param source [Spree::PaymentSource, nil] optionally, payment source from which
+    #   to create the authorization
+    # @param _transaction_id [Object] (currently ignored)
+    # @param options [Hash]
+    # @option options [Spree::Payment] :originator the payment on which the #capture is
+    #   being performed (required if source is nil)
+    #
+    # @return ActiveMerchant::Billing::Response
+    def credit(amount_in_cents, source, _transaction_id, options = {})
+      currency = options.fetch(:currency)
+      source ||= options[:originator].source
+
+      refund, _response = client.request do
+        Stripe::Refund.create(
+          amount: MoneyToStripeAmountConverter.to_stripe_amount(amount_in_cents, currency),
+          payment_intent: source.stripe_payment_intent_id,
+        )
+      end
+
+      ActiveMerchant::Billing::Response.new(
+        true, "PaymentIntent was refunded successfully", { 'stripe_refund' => refund.to_json }, {}
+      )
     end
 
     module MoneyToStripeAmountConverter
@@ -105,4 +203,3 @@ def to_stripe_amount(fractional, currency)
     end
   end
 end
-# rubocop:enable Style/MethodCallWithoutArgsParentheses, Lint/UnusedMethodArgument

app/models/solidus_stripe/payment_method.rb

@@ -3,6 +3,19 @@
 module SolidusStripe
   class PaymentMethod < ::Spree::PaymentMethod
     preference :api_key, :string
+    preference :publishable_key, :string
+
+    def partial_name
+      "stripe"
+    end
+
+    def cart_partial_name
+      "stripe"
+    end
+
+    def product_page_partial_name
+      "stripe"
+    end
 
     def payment_source_class
       PaymentSource
@@ -12,6 +25,20 @@ def gateway_class
       Gateway
     end
 
+    def create_profile(payment)
+      payment_intent = payment.source.payment_intent
+
+      if payment_intent && payment_intent.customer.blank?
+        payment.payment_method.gateway.client.request do
+          payment_intent.customer = Stripe::Customer.new email: payment.order.email
+          payment_intent.customer.save
+          payment_intent.save
+        end
+      end
+
+      self
+    end
+
     def payment_profiles_supported?
       true
     end

app/models/solidus_stripe/payment_source.rb

@@ -4,5 +4,23 @@
 
 module SolidusStripe
   class PaymentSource < ::Spree::PaymentSource
+    alias_attribute :gateway_payment_profile_id, :stripe_payment_intent_id
+    alias_attribute :gateway_payment_profile_id=, :stripe_payment_intent_id=
+
+    def payment_intent
+      return nil if stripe_payment_intent_id.blank?
+
+      payment_intent, _response = payment_method.gateway.client.request do
+        Stripe::PaymentIntent.retrieve(stripe_payment_intent_id)
+      end
+
+      payment_intent
+    end
+
+    def stripe_dashboard_url
+      path_prefix = '/test' if payment_method.preferred_test_mode
+
+      "https://dashboard.stripe.com#{path_prefix}/payments/#{stripe_payment_intent_id}"
+    end
   end
 end

app/views/spree/admin/payments/source_views/_stripe.html.erb

@@ -0,0 +1,16 @@
+<fieldset data-hook="credit_card">
+  <legend align="center"><%= SolidusStripe::PaymentSource.model_name.human %></legend>
+
+  <div class="row">
+    <div class="col-4">
+      <dl>
+        <dt><%= SolidusStripe::PaymentSource.human_attribute_name(:stripe_payment_intent_id) %>:</dt>
+        <dd><%= link_to(
+          payment.source.stripe_payment_intent_id,
+          payment.source.stripe_dashboard_url,
+          target: :_blank,
+        ) %></dd>
+      </dl>
+    </div>
+  </div>
+</fieldset>

bin/dev

@@ -0,0 +1,8 @@
+#!/usr/bin/env sh
+
+if ! gem list foreman -i --silent; then
+  echo "Installing foreman..."
+  gem install foreman
+fi
+
+exec foreman start -f Procfile.dev "$@"

bin/rspec

@@ -1,11 +1,5 @@
-#!/usr/bin/env bash
+#!/usr/bin/env ruby
 
-set -e
-
-bin/rails-dummy-app generate solidus_stripe:install --force --migrate --specs=all
-
-cd dummy-app/
-rspec "$@"
-exit_status=$?
-cd -
-exit $exit_status
+system "bin/rails-dummy-app generate solidus_stripe:install --force --migrate --specs=all --sync"
+Dir.chdir "dummy-app/"
+exec "rspec", *ARGV