Benmudge.com PayHere Webhooks integration

payhere_webhooks_controller.rb

module Events
  class PayhereWebhooksController < ApplicationController
    skip_before_action :authenticate_user!
    skip_before_action :verify_authenticity_token

    def create
      return head 401 unless valid_signature?

      if payment_params[:status] == "success"
        user = find_or_create_user
        payment = find_or_create_payment_for(user)

        if new_user?
          SlackNotifierJob.perform_async("#{user.name} (#{user.email}) just subscribed for £#{payment.amount}")
          UserMailer.welcome(user).deliver_later
        else
          SlackNotifierJob.perform_async("#{user.name} (#{user.email}) subscription just renewed for £#{payment.amount}")
        end
      end

      head :no_content
    end

    private

    def valid_signature?
      digest = OpenSSL::Digest.new("sha1")
      expected = OpenSSL::HMAC.hexdigest(digest, ENV["PAYHERE_SHARED_SECRET"].to_s, request.raw_post)

      Rack::Utils.secure_compare(expected, request.headers["HTTP_X_SIGNATURE"])
    end

    def find_or_create_payment_for(user)
      user.payments.find_by(payhere_id: payment_params[:payhere_id]) || user.payments.create!(payment_params)
    end

    def new_user?
      @new_user.present?
    end

    def find_or_create_user
      if (user = User.find_by(email: user_params[:email]))
        user.update(active_until: (1.month.from_now + 1.day).beginning_of_day)
        user
      else
        @new_user = true
        User.create!(user_params)
      end
    end

    def user_params
      {
        name: params.dig(:customer, :name),
        email: params.dig(:customer, :email),
        password: SecureRandom.hex(16),
        subscription_status: "active",
        active_until: payment_params[:amount_in_cents] < 2001 ? (1.month.from_now + 1.day).beginning_of_day : (3.months.from_now + 1.day).beginning_of_day
      }
    end

    def payment_params
      {
        amount_in_cents: params.dig(:payment, :amount).to_i * 100,
        payhere_id: params.dig(:payment, :hashid),
        status: params.dig(:payment, :status),
        secure_token: params.dig(:payment, :secure_token),
        card_brand: params.dig(:payment, :card_brand),
        card_last4: params.dig(:payment, :card_last4)
      }
    end
  end
end