gluon/package/gluon-status-page/src/js/lib/helper.js

"use strict"
define([ "bacon" ], function (Bacon) {
  function get(url) {
    return Bacon.fromBinder(function(sink) {
      var req = new XMLHttpRequest()
      req.open("GET", url)

      req.onload = function() {
        if (req.status === 200)
          sink(new Bacon.Next(req.response))
        else
          sink(new Bacon.Error(req.statusText))
        sink(new Bacon.End())
      }

      req.onerror = function() {
        sink(new Bacon.Error("network error"))
        sink(new Bacon.End())
      }

      req.send()

      return function () {}
    })
  }

  function getJSON(url) {
    return get(url).map(JSON.parse)
  }

  function buildUrl(ip, object, param) {
    var url = "http://[" + ip + "]/cgi-bin/" + object
    if (param) url += "?" + param

    return url
  }

  function request(ip, object, param) {
    return getJSON(buildUrl(ip, object, param))
  }

  function dictGet(dict, key) {
    var k = key.shift()

    if (!(k in dict))
      return null

    if (key.length === 0)
      return dict[k]

    return dictGet(dict[k], key)
  }

  function haversine() {
    var radians = Array.prototype.map.call(arguments, function(deg) { return deg / 180.0 * Math.PI })
    var lat1 = radians[0], lon1 = radians[1], lat2 = radians[2], lon2 = radians[3]
    var R = 6372.8 // km
    var dLat = lat2 - lat1
    var dLon = lon2 - lon1
    var a = Math.sin(dLat / 2) * Math.sin(dLat / 2) + Math.sin(dLon / 2) * Math.sin(dLon / 2) * Math.cos(lat1) * Math.cos(lat2)
    var c = 2 * Math.asin(Math.sqrt(a))
    return R * c
  }

  return { buildUrl: buildUrl
         , request: request
         , getJSON: getJSON
         , dictGet: dictGet
         , haversine: haversine
         }
})