Ruby version of Questbook's "Writing a blockchain in Python"

blockchain.rb

require 'digest'
require 'json'

class Chain
  def initialize
    @blockchain = []
    @pending = []
  end

  def add_block(proof)
    block = {
      index: @blockchain.length,
      timestamp: Time.now,
      transactions: @pending,
      proof: proof,
      prevhash: (@blockchain[-1].nil? ? 'Genesis' : compute_hash(@blockchain[-1]))
    }

    @blockchain.push(block)
    @pending = []
  end

  def add_transaction(sender, recipient, amount)
    transaction = {
      sender: sender,
      recipient: recipient,
      amount: amount
    }

    @pending.push(transaction)
  end

  def compute_hash(block)
    Digest::SHA256.hexdigest(block.to_json)
  end
end


chain = Chain.new
t1 = chain.add_transaction("Vitalik", "Satoshi", 100)
t2 = chain.add_transaction("Satoshi", "Alice", 10)
t3 = chain.add_transaction("Alice", "Charlie", 34)
chain.add_block(12345)

t4 = chain.add_transaction("Bob", "Eve", 23)
t5 = chain.add_transaction("Dennis", "Brian", 3)
t6 = chain.add_transaction("Ken", "Doug", 88)
chain.add_block(6789)

puts chain.instance_variable_get(:@blockchain)


# Output:
=begin
{
  :index=>0,
  :timestamp=>2021-11-17 00: 25: 17 +0530,
  :transactions=>[
    {
      :sender=>"Vitalik",
      :recipient=>"Satoshi",
      :amount=>100
    },
    {
      :sender=>"Satoshi",
      :recipient=>"Alice",
      :amount=>10
    },
    {
      :sender=>"Alice",
      :recipient=>"Charlie",
      :amount=>34
    }
  ],
  :proof=>12345,
  :prevhash=>"Genesis"
}
{
  :index=>1,
  :timestamp=>2021-11-17 00: 25: 17 +0530,
  :transactions=>[
    {
      :sender=>"Bob",
      :recipient=>"Eve",
      :amount=>23
    },
    {
      :sender=>"Dennis",
      :recipient=>"Brian",
      :amount=>3
    },
    {
      :sender=>"Ken",
      :recipient=>"Doug",
      :amount=>88
    }
  ],
  :proof=>6789,
  :prevhash=>"0e98e3e1d8f8c605ba91dfbb98e80efc3f6bf18f03567b8446ffc07f8d9e8dae"
}
=end