upload a pac which have self as a proxy server

iProxy.rake

require 'rest_client'

class KVStore
  def self.shared_instance
    @@_shared_instance ||= RestClient::Resource.new("http://api.openkeyval.org")
  end

  def self.store(key, value = nil)
    shared_instance[key].post({:data => value})
  end

  def self.delete(key)
    store(key)
  end

  def self.get(key)
    shared_instance[key].get
  end
end

def get_local_ips
  `ifconfig | grep "inet[^6]192" | sed "s/^.*inet\ //" | sed "s/\ netmask.*$//"`
end

def pac_template(local_ip = nil, port = 8080)
  if local_ip
    return "function FindProxyForURL(url, host) { return \"PROXY #{local_ip}:#{port}; DIRECT\"; }"
  else
    return "function FindProxyForURL(url, host) { return \"DIRECT\"; }"
  end
end

def gen_pac
  local_ip_list = get_local_ips.split

  pac_template local_ip_list[0]
end

def gen_empty_pac
  pac_template
end

task :default => :upload_pac

task :upload_pac do
  remote_ip = ""
  begin
    remote_ip = File.read(File.expand_path("../tmp/remote", __FILE__))
  rescue
    FileUtils.mkpath(File.expand_path("../tmp", __FILE__))
  end
  KVStore.store("stranbird_ip", gen_pac) and IO.write(File.expand_path("../tmp/remote", __FILE__), get_local_ips[0]) unless remote_ip != get_local_ips[0]
end

task :clear_pac do
  KVStore.store("stranbird_ip", gen_empty_pac)
end

本地储存服务器设置。
下次更新的时候，如果本地设置和服务器设置匹配，就不需要更新了。