Accept Payments with Paystack in Ruby on Rails

Add your Paystack key to Rails credentials or .env:

# .env
PAYSTACK_SECRET_KEY=sk_test_xxxxxxxxxxxxxxxxxxxxx

Add the dotenv gem if using .env:

# Gemfile
gem 'dotenv-rails', groups: [:development, :test]

# app/services/paystack_service.rb
require 'net/http'
require 'json'

class PaystackService
  BASE_URL = 'https://api.paystack.co'

  def initialize
    @secret_key = ENV['PAYSTACK_SECRET_KEY']
  end

  def initialize_transaction(email:, amount_kobo:, reference:, callback_url:)
    uri = URI(BASE_URL + '/transaction/initialize')
    http = Net::HTTP.new(uri.host, uri.port)
    http.use_ssl = true

    request = Net::HTTP::Post.new(uri)
    request['Authorization'] = 'Bearer ' + @secret_key
    request['Content-Type'] = 'application/json'
    request.body = {
      email: email,
      amount: amount_kobo,
      reference: reference,
      callback_url: callback_url
    }.to_json

    response = http.request(request)
    JSON.parse(response.body)
  end

  def verify_transaction(reference)
    uri = URI(BASE_URL + '/transaction/verify/' + reference)
    http = Net::HTTP.new(uri.host, uri.port)
    http.use_ssl = true

    request = Net::HTTP::Get.new(uri)
    request['Authorization'] = 'Bearer ' + @secret_key

    response = http.request(request)
    JSON.parse(response.body)
  end
end

# app/controllers/payments_controller.rb
class PaymentsController < ApplicationController
  def create
    email = params[:email]
    amount = params[:amount].to_f
    reference = "order_#{SecureRandom.hex(6)}"

    order = Order.create!(
      email: email,
      amount_kobo: (amount * 100).to_i,
      reference: reference
    )

    service = PaystackService.new
    result = service.initialize_transaction(
      email: email,
      amount_kobo: order.amount_kobo,
      reference: reference,
      callback_url: payment_callback_url
    )

    if result['status']
      redirect_to result['data']['authorization_url'], allow_other_host: true
    else
      flash[:error] = result['message'] || 'Failed'
      redirect_to checkout_path
    end
  end

  def callback
    reference = params[:reference] || params[:trxref]

    unless reference
      flash[:error] = 'Missing reference'
      return redirect_to root_path
    end

    service = PaystackService.new
    result = service.verify_transaction(reference)

    if result['status'] && result['data']['status'] == 'success'
      order = Order.find_by(reference: reference)

      if order && result['data']['amount'] == order.amount_kobo
        Order.where(reference: reference, paid: false).update_all(paid: true, paid_at: Time.current)
        render :success
      else
        render :failed
      end
    else
      render :failed
    end
  end
end

# config/routes.rb
Rails.application.routes.draw do
  post '/pay', to: 'payments#create'
  get '/payment/callback', to: 'payments#callback', as: :payment_callback
end

rails generate model Order reference:string:uniq email:string amount_kobo:integer currency:string paid:boolean paid_at:datetime
rails db:migrate

1. Use Rails credentials. Store keys with rails credentials:edit instead of .env in production.
2. Set up webhooks. See Handle Paystack Webhooks in Rails.
3. HTTPS. Required for callback and webhook URLs.
4. Validate amounts. Check against your database, not params.

This guide is part of the Paystack integration guides by language and framework series.

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