Get BTC price history from BitcoinCharts and output in ledger prices_db format

get_prices_db.rb

#!/usr/bin/env ruby
# Set these to what you'd like
symbol = "mtgoxUSD"
ledger_currency = "$"
ledger_btc = "BTC"
start_date = "2013-01-01"
end_date = Time.now.to_i

# shouldn't really need to change anything after here
require 'open-uri'
require 'csv'

url = "http://bitcoincharts.com/t/trades.csv?symbol=%s&start=%d&end=%d" % [symbol, Date.parse(start_date).to_time.to_i, end_date]

puts "D %s1,000.00\nN %s" % [ledger_currency, ledger_currency]

CSV.foreach open(url) do |line|
  time = line[0].to_i
  price = line[1].to_f
  amount = line[2].to_f
  puts "P %s %s %s%f" % [ 
              Time.at(time).strftime("%Y-%m-%d %H:%M:%S"),
              ledger_btc,
              ledger_currency,
              price 
                        ]
end