Payment Processor Simulator

A payment processor simulator

Features

• Card and bank details RSA encrypted before stored
• Exception on credit cards starting with 1111 or 8888
• Exception on any expiry date in the past
• Bank routing numbers are validated
• Payouts made net of fees assessed at 2.9% + 30c per transaction or 1% + $1 for a bank transfer
• Transactions marked paid via date_paid_out after payout processing

Usage

main.rb is the program entry point

ruby main.rb

Usage Examples

Merchants

Create a Merchant

merchant_amazon = Merchant.new("Amazon")

Credit Card Transactions

Create a Credit Card

credit_card = CreditCard.new(
  card_number=4242424242424242,
  expiry=(Date.today + 365),
  cvv="123",
  billing_zip=92509,
)

Create a Credit Card Transaction

cc_transaction = CreditCardTransaction.new(
  credit_card,
  today,
  6.55,
  merchant_amazon
)

Bank Account Transactions

Create a Bank Account

bank_account = BankAccount.new(
  "01100001534214",
  routing_number="011000015"
)

Create a Bank Account Transaction

bank_transaction = BankTransaction.new(
  bank_account,
  today,
  12.23,
  merchant_ebay
)

Payment Processor

Create a Payment Processor

payment_processor = PaymentProcessor.new

Accept Transactions

payment_processor.accept(cc_transaction)
payment_processor.accept(bank_transaction)

Create Payouts given a Date

payouts = payment_processor.payout(today)

Audit

Pretty Print Transactions and Payouts

payment_processor.audit_date_and_merchant(today, merchant_ebay)
payment_processor.audit_payouts(payouts)

RSA Encryption

Sample Ruby RSA Encryption and Decryption scripts

require 'openssl'
require 'base64'

# 1. Generate a private.pem key file
# > openssl genrsa -des3 -out private.pem 2048
# config/rsa/private.pem
#
# 2. password: paymentprocessor
# 
# 3. Generate public.pem keyfile
# > openssl rsa -in private.pem -out public.pem -outform PEM -pubout
# config/rsa/public.pem

# Encrypt a string using public.pem keyfile
public_key_file = "./config/rsa/public.pem"
string = "Hello World!"
public_key = OpenSSL::PKey::RSA.new(File.read(public_key_file))
encrypted_string = Base64.encode64(public_key.public_encrypt(string))
p encrypted_string

# Decrypt an encrypted string using private.pem keyfile
private_key_file = './config/rsa/private.pem';
password = 'paymentprocessor'
private_key = OpenSSL::PKey::RSA.new(File.read(private_key_file),password)
string = private_key.private_decrypt(Base64.decode64(encrypted_string))

print string, "\n"

Tests

Sample payment_processor_spec.rb RSpecs

Run Tests

> bundle exec rspec

Improvements

• RSpec standard output suppression
• Audit methods output format cleanup
• In payout.rb, instead of calculate_lump_sum_payout, consider running sum
• In payment_processor.rb, consider selecting transactions in one pass
• More specs, boundary case specs
• 'require' cleanup
• Web or desktop app w/ database
• Use cents (int) to transfer, store, and calculate price data, etc.