http__tp_link_wa901nd

#!/usr/bin/env ruby

if $0 =~ /^(?:|.*\/)http_([^_]+)_/
  host = $1
end
abort "# Error: couldn't understand what I'm supposed to monitor." unless host

user = ENV['user'] || 'admin'
password = ENV['password'] || 'admin'

require 'resolv'
require 'digest/md5'
require 'base64'
require 'cgi'
require 'csv'
require 'net/http'

class DeviceStats
  def initialize(host, user, password)
    @host = Resolv.getaddress(host)
    @auth_cookie = build_auth_cookie(user, password)
  end

  def wireless_channel
    stats = extract_js_array(status_page, 'wlanPara')
    return nil if stats.nil?

    if stats[2] == "15"
      stats[9].to_i
    else
      stats[2].to_i
    end
  end

  def connected_clients
    data = extract_js_array(wireless_stats_page, 'wlanHostPara')
    return nil if data.nil?

    data[0].to_i
  end

  def uptime
    data = extract_js_array(status_page, 'statusPara')
    return nil if data.nil?

    data[4].to_f / 86400.0
  end

  private

  def extract_js_array(page, name)
    if page =~ %r{#{Regexp.escape(name)}\s+=\s+new\s+Array\((.+?)\)}m
      CSV.parse_line($1.gsub(/\n/, ''))
    else
      nil
    end
  end

  def status_page
    @status_page ||= get_status_page.body
  end

  def wireless_stats_page
    @wireless_stats_page ||= get_wireless_stats_page.body
  end

  def logout
    return if @url_token.nil?
    get_page(path_with_token('/userRpm/LogoutRpm.htm'))
    @url_token = nil
  end

  def get_status_page
    get_page(path_with_token('/userRpm/StatusRpm.htm'))
  end

  def get_wireless_stats_page
    get_page(path_with_token('/userRpm/WlanStationRpm.htm'))
  end

  def path_with_token(path)
    @url_token ||= get_url_token
    "/#{@url_token}#{path}"
  end

  def get_url_token
    get_page('/', false)
    resp = get_page('/userRpm/LoginRpm.htm?Save=Save', false)
    if resp.body =~ %r{http://#{Regexp.escape(@host)}/([A-Za-z0-9]+)/}
      at_exit { logout }
      return $1
    else
      return nil
    end
  end

  def get_page(path, include_referrer = true)
    Net::HTTP.start(@host, 80) do |http|
      req = Net::HTTP::Get.new(path)
      req['Cookie'] = @auth_cookie
      if include_referrer
        req['Referer'] = "http://#{@host}#{path_with_token('/userRpm/Index.htm')}"
      end
      http.request(req)
    end
  end

  def build_auth_cookie(user, password)
    hashed_password = Digest::MD5.hexdigest(password)
    value = Base64.encode64("#{user}:#{hashed_password}").strip
    'Authorization=Basic%20' + CGI.escape(value)
  end
end

if (ARGV[0] == 'config')
  puts "host_name #{host}" unless host == 'localhost'

  puts "multigraph wireless_channel"
  puts "graph_title Wireless Channel"
  puts "graph_args --base 1000 -l 0"
  puts "graph_vlabel channel"
  puts "graph_category network"
  puts "channel.label Channel"
  puts "channel.type GAUGE"
  puts "channel.min 0"
  puts "channel.draw LINE1"

  puts "multigraph connected_clients"
  puts "graph_title Connected Clients"
  puts "graph_args --base 1000 -l 0"
  puts "graph_vlabel clients"
  puts "graph_category network"
  puts "clients.label Clients"
  puts "clients.type GAUGE"
  puts "clients.min 0"
  puts "clients.draw LINE1"

  puts "multigraph uptime"
  puts "graph_title System Uptime"
  puts "graph_args --base 1000 -l 0"
  puts "graph_vlabel uptime in days"
  puts "graph_category system"
  puts "uptime.label uptime"
  puts "uptime.type GAUGE"
  puts "uptime.draw AREA"

  exit 0
end

stats = DeviceStats.new(host, user, password)

puts "multigraph wireless_channel"
puts "channel.value #{stats.wireless_channel.nil? ? 'U' : stats.wireless_channel}"

puts "multigraph connected_clients"
puts "clients.value #{stats.connected_clients.nil? ? 'U' : stats.connected_clients}"

puts "multigraph uptime"
puts "uptime.value #{stats.uptime || 'U'}"