This is a quick little snippet I'm whipping up to import some historical data in for a graphing app we're building for stock data. I figured I'd post this snippet before I maul it into something application-specific...

It downloads a csv file through yahoo's finance site and then parses it and prints out the date and adjusted close for each business day that has data.

require 'open-uri'
require 'csv'

def get_adjusted_close stock_symbol
  puts "-- #{stock_symbol} Adjusted Close - Historical --"
  url = "http://ichart.finance.yahoo.com/table.csv?s=#{stock_symbol}&d=7&e=1&f=2006&g=d&a=2&b=26&c=1990&ignore=.csv"
  puts "Connecting to #{url}\n"

  csv = CSV.parse(open(url).read)

  csv.each{|row|
    puts "#{row[0]} - #{row.last}"
  }
  puts "---------------------------------"
end

example_stocks = "CSCO GOOG"
print "Enter a series of stock symbols separated by spaces (example: #{example_stocks}) to retrieve the historical adjusted close.\n"
stock_symbols = gets
stock_symbols ||= example_stocks

stock_symbols.split.each{|symbol|
  get_adjusted_close(symbol)
}