aria2 downloader

xcode.rb

require 'rubygems'
require 'mechanize'

if ARGV.size < 3
  puts %q{Usage: ruby xcode.rb USERNAME PASSWORD "DOWNLOAD_URL" [WGET_PARAMS]}
  puts %q{Example: ruby xcode.rb [email protected] 123456  "https://developer.apple.com/devcenter/download.action?path=/Developer_Tools/xcode_4_and_ios_sdk_4.3__final/xcode_4_and_ios_sdk_4.3__final.dmg"  }
  exit
end

a = Mechanize.new { |agent|
  agent.user_agent_alias = 'Mac Safari'
}

a.get('https://developer.apple.com/') do |page|
  member_page = a.click(page.link_with(:text => /Member Center/))
  login = member_page.form_with(:name => 'appleConnectForm') do |form|
    form.theAccountName  = ARGV[0]
    form.theAccountPW = ARGV[1]
  end.submit

  a.redirect_ok = false
  download_page = a.get(ARGV[2])  
  system %Q{ aria2c -c -s10 -x10 #{download_page.response["location"]} --header "Cookie: #{download_page.response["set-cookie"]}" #{ARGV[3]}}
end

another solution using Cookie Export to export cookies to cookies.txt

aria2c -c -x10 -s10 -U 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:33.0) Gecko/20100101 Firefox/33.0' --load-cookies=cookies.txt https://developer.apple.com/services-account/download\?path\=/iOS/iOS_9_beta_5/iOS_9_beta_5__iPhone_5s_Model_A1457_A1518_A1528_A1530__13A4325c.zip

Tried @kukat 's Cookie Export one, it worked.