bitcoin_client.rb

require 'json'
require 'net/http'
require 'bigdecimal'
require 'bigdecimal/util'

class BitcoinClient
  def initialize(config_file = File.expand_path("~/.bitcoin/bitcoin.conf"), host = '127.0.0.1', port = 8332)
    raise "missing config file" if !File.exist?(config_file)

    config = File.read(config_file).each_line.inject({}) do |hash, line|
      key, value = line.chomp.split(/=/, 2)
      hash[key] = value
      hash
    end

    @username = config['rpcuser']
    raise "missing username from configuration" if @username.nil?
    @password = config['rpcpassword']
    raise "missing password from configuration" if @password.nil?

    @host = host
    @port = port
    @command_id = 1
  end

  def balance
    request('getbalance').to_d
  end

  def set_passphrase(passphrase, timeout = 10)
    request('walletpassphrase', passphrase, timeout)
  end

  def send_amount(address, amount)
    request('sendtoaddress', address, amount.to_f)
  end

  def list_transactions(account = "", count = 10, from = 0)
    request('listtransactions', account, count, from)
  end

  def request(method, *args)
    out = {}
    req = Net::HTTP::Post.new("/", {"Content-Type" => "application/json"})
    req.basic_auth(@username, @password)
    params = { 'method' => method, 'params' => args, 'id' => @command_id }
    Net::HTTP.start(@host, @port) do |conn|
      res = conn.request(req, params.to_json)
      out = JSON.parse(res.body)
    end
    if error = out["error"]
      raise error["message"]
    end
    if out["id"] != @command_id
      raise "id mismatch, expected #{@command_id.inspect}, got #{result["id"].inspect}"
    end
    @command_id += 1
    out['result']
  end
end