rails-pay-checkout-demo

Stripe integration with Rails and the Pay gem for Subscription Billing.

Table of Contents

• Stripe Checkout
  • The sequence of events for Stripe Checkout are
  • Products and Prices
• The Pay Integration
  • Set up your payment processor credentials and initializers
    • Stripe Credentials
    • Initializers
  • Add the pay_customer Class Method to the User Model
  • Request a Checkout URL and Redirect the User
    • Checkout URL Generator
  • Handle Stripe Events
    • Stripe CLI
    • The Payment Succeed Event
• Appendix
  • Relevant Files
• Related Articles

Stripe Checkout

Stripe Checkout Stripe Checkout is a checkout flow where Stripe hosts the payments page that collects the credit card details.

The sequence of events for Stripe Checkout are:

1. A checkout session is created.
2. The user is redirected to Stripe's payment page.
3. The user completed a payment on Stripe's page.
4. The user is redirected back to the app.
5. The app receives a "payment success" webhook from Stripe.

Products and Prices

Products and prices are used for subscription billing in lieu of plans. In this app, each "plan" is its own product, and each product has a single price.

The Pay Integration

To complete the integration

1. Set up your payment processor credentials and initializers.
2. Add the pay_customer the User Model.
3. Request a Checkout URL and Redirect the User
4. Handle Stripe Events

Set up your payment processor credentials and initializers {#initializers}

Stripe Credentials

Follow Pay's configuration instructions to set up your Stripe credentials.

Initializers

1. Create or update the stripe.rb initializer.
2. Create the pay.rb initializer.

Add the pay_customer Class Method to the User Model

1. Generate the Pay Models:

   • Pay is already installed. For a fresh app, run bin/rails pay:install:migrations to create the necessary Pay models.

2. Update the User Model:

   • Add pay_customer to the User model:

     class User < ApplicationRecord
       pay_customer
     end

Including pay_customer in the User model establishes an internal association between the User and the Pay::Customer model. This association uses the owner_type and owner_id fields.

payment_processor is the entry point to Pay's functionality. By including pay_customer in the User model, the payment_processor method becomes available on all User instances, providing access to customer, subscription, and charge models.

Request a Checkout URL and Redirect the User

Using Pay, request a checkout URL from Stripe and then redirect the user to that URL. Once the transaction is complete, Stripe will return the user to the URL defined by success_URL, along with a session_id.

Checkout URL Generator

def checkout
  user.payment_processor.checkout(
    mode: "subscription",
    line_items: stripe_price_id,
    success_url: success_url,
    billing_address_collection: "auto",
    allow_promotion_codes: false,
  )
end

Handle Stripe Events

Stripe CLI

The Pay Gem requires Stripe Webhooks to function properly. When building the Pay integration locally, you'll need to set up the Stripe CLI and have it running to forward the events to your app.

$ stripe listen --forward-to localhost:3000/pay/webhooks/stripe

Update your stripe credentials to include the webhook signing secreted generated by the CLI.

The Payment Succeed Event

When Stripe processes a payment successfully, it triggers the invoice.payment_succeeded [event] (https://github.com/pay-rails/pay/tree/main/test/pay/stripe/webhooks). Use this event to initiate other workflows in Rails. For instance, access a paid feature or a custom receipt.

class PaymentSucceededHandler
  def call(event)
    pay_charge = Pay::Stripe::Charge.sync(
      event.data.object.charge,
      stripe_account: event.try(:account)
    )
    return if pay_charge.nil?

    adjust_user(pay_charge)
  end

  def adjust_user(pay_charge)
    user = pay_charge.customer.owner
    user.update!(updated_at: Time.zone.now)
  end
end

Appendix

Relevant Files

1. user.rb
2. app/controllers/static_controller.rb
3. app/controllers/checkouts_controller.rb
4. config/environments/development.rb
5. app/services/stripe_checkout.rb
6. app/services/payment_succeded_handler.rb
7. config/initializers/pay.rb
8. config/initializers/stripe.rb

Related Articles

1. Stripe Checkout
2. Routes and Webhooks
3. Stripe Webhooks