Fix facebook broken exported UTF

CSV-from-facebook-friends-export.rb

require 'json'
require 'uri'
require 'csv'

# too bad we lack variable size lookbehind
bytes_re = /((?:\\\\)+|[^\\])(?:\\u[0-9a-f]{4})+/

friends_txt = File.read('friends.json').gsub(bytes_re) do |bad_unicode|
  $1 + eval(%Q{"#{bad_unicode[$1.size..-1].gsub('\u00', '\x')}"}).to_json[1...-1]
end

friends = JSON.load(friends_txt)["friends"]

result = friends.map { |friend|
  friend.tap { |f|
    f["since"] = "#{Time.at(f.delete("timestamp"))}"
    f["status"] = ""
    f["url"] = URI::HTTP.build(schema: "https", host: "www.facebook.com", path: "/search/people", query: URI.encode_www_form({ q: f["name"]}))
  }
}

# export to a CSV to import into some spreadsheet program
CSV.open("data.csv", "w", headers: result.first.keys, write_headers: true) do |csv|
  result.each { |h| csv << h.values }
end