gas_price.rb

require 'spreadsheet'
require 'pry'
require 'open-uri'
require 'yaml'

# Download spreadsheet
website = "http://www.eia.gov/dnav/ng/hist/n9190us3m.htm"

web_base = "http://www.eia.gov/dnav/ng/hist_xls/"
file_name = open('http://www.eia.gov/dnav/ng/hist/n9190us3m.htm').read.scan(/([\w]+\.xls)/)[0][0]
if file_name
  web_location = web_base + file_name
else
 web_location = "http://www.eia.gov/dnav/ng/hist_xls/N9190US3a.xls"
end

xls = open(web_location).read 
xls_location = "/tmp/#{file_name}#{$$}"
File.open(xls_location, 'w') { |f| f.write xls }

          
# save_location = ''

# Parse spreadsheet

Spreadsheet.client_encoding = 'UTF-8'

book = Spreadsheet.open(xls_location)

@sheet1 = book.worksheet 1

@info = {}

def parse_excel
  41.upto(1000).each do |i| # Jump ahead to useful part of excel worksheet
  r = @sheet1.row(i)
  next if r[0].nil? || r[1].nil? # Avoid nil errors
  @info[r[0].to_date.strftime('%Y-%m-%d')] = sprintf "%.2f", r[1] # Sprintf for 2 decimals
  end
  
  @info
end

# Cleanup
File.unlink(xls_location) 

# Run parse_excel function to do work
parse_excel

# Write to local location
# 
#
# To pull most recent price
# @info.sort.last
output = '../logs/gas_price.yml'
File.unlink(output) if File.exists?(output)

File.open(output, 'w') { |f| f.write @info.sort.to_yaml }