Convert JSON to CSV using Ruby

json-to-csv

#!/usr/bin/env ruby

# USAGE:
# 
# json-to-csv [filename]
# 
# This script takes a JSON array of objects as its input and outputs
# the data as CSV to STDOUT. The JSON array can be fed to the
# script either via STDIN or by supplying a filename as an argument.

require 'csv'
require 'json'

data = JSON.parse ARGF.read
headers = data.reduce([]) {|memo, x| (memo + x.keys).uniq }

csvstring = CSV.generate do |csv|
  csv << headers
  data.each {|x| csv << x.values_at(*headers) }
end

puts csvstring