external.js

/* eslint-env browser */

(function(window, hostname) {
  if (!window) return
  var nav = window.navigator
  var loc = window.location
  var host = loc.hostname
  var doc = window.document
  var con = window.console
  var perf = window.performance
  var uri = '//' + hostname
  var targetOrigin = 'https://' + hostname

  // A simple log function so the user knows why a request is not being send
  var warn = function(message) {
    if (con && con.warn) con.warn('Simple Analytics: ' + message)
  }

  try {
    var userAgent = nav.userAgent
    var dis = window.dispatchEvent
    var lastSendUrl
    var notSending = 'Not sending requests '

    var attr = function(script, attribute) { return script && script.getAttribute('data-' + attribute) }

    var script = doc.querySelector('script[src$="' + uri + '/app.js"]')
    var mode = attr(script, 'mode')
    var skipDNT = attr(script, 'skip-dnt') === 'true'
    var functionName = attr(script, 'sa-global') || 'sa'

    // Don't track when host is localhost
    if (host === 'localhost') return warn(notSending + 'from localhost')

    // We do advanced bot detection in our API, but this line filters already most bots
    if (/(bot|spider|crawl)/i.test(userAgent)) return warn(notSending + 'because user agent is a robot')

    var getParams = function(regex) {
      // From the search we grab the utm_source and ref and save only that
      var matches = loc.search.match(new RegExp('[?&]('+regex+')=([^?&]+)', 'gi'))
      var match = matches ? matches.map(function(m) { return m.split('=')[1] }) : []
      if (match && match[0]) return match[0]
    }

    var ref = getParams('utm_source|source|ref')
    var campaign = getParams('utm_campaign|campaign')
    var cleanRef = doc.referrer.replace(/^https?:\/\/((m|l|w{2,3}([0-9]+)?)\.)?([^?#]+)(.*)$/, '$4').replace(/^([^/]+)\/$/, '$1') || null

    var post = function(isPushState) {
      // Obfuscate personal data in URL by dropping the search and hash
      var url = loc.protocol + '//' + host + loc.pathname

      // Add hash to url when script is put in to hash mode
      if (mode === 'hash' && loc.hash) url += loc.hash.split('?')[0]

      // Don't send the last URL again (this could happen when pushState is used to change the URL hash or search)
      if (lastSendUrl === url) return
      lastSendUrl = url

      // Don't track when Do Not Track is set to true
      if (!skipDNT && 'doNotTrack' in nav && nav.doNotTrack === '1') return warn(notSending + 'when doNotTrack is enabled')

      var data = { url: url }
      if (userAgent) data.ua = userAgent
      if (ref) data.urlReferrer = ref
      if (cleanRef && !isPushState) data.referrer = cleanRef
      if (window.innerWidth) data.width = window.innerWidth

      // We put new code always in a try block to prevent huge issues
      try {
        // Check if back, forward or reload buttons are being use in modern browsers
        var backModern = (perf && perf.getEntriesByType && perf.getEntriesByType('navigation')[0] && perf.getEntriesByType('navigation')[0].type)
          ? ['reload', 'back_forward'].indexOf(perf.getEntriesByType('navigation')[0].type) > -1
          : null

        // Check if back, forward or reload buttons are being use in older browsers
        var back = typeof backModern === 'boolean'
          ? backModern
          : perf && perf.navigation && perf.navigation.type && [perf.navigation.TYPE_RELOAD, perf.navigation.TYPE_BACK_FORWARD].indexOf(perf.navigation.type) > -1

        // We set unique variable based on pushstate or back navigation, if no match we check the referrer
        data.unique = isPushState || back ? false : doc.referrer && doc.referrer.split('/')[2] !== loc.hostname;
      } catch (error) {
        // nothing
      }

      try {
        data.timezone = Intl.DateTimeFormat().resolvedOptions().timeZone
      } catch (error) {
        // nothing
      }

      var request = new XMLHttpRequest()
      request.open('POST', uri + '/api', true)

      // We use content type text/plain here because we don't want to send an
      // pre-flight OPTIONS request
      request.setRequestHeader('Content-Type', 'text/plain; charset=UTF-8')
      request.send(JSON.stringify(data))
    }

    // Thanks to https://gist.github.com/rudiedirkx/fd568b08d7bffd6bd372
    var his = window.history
    var hisPushState = his ? his.pushState : null
    if (hisPushState && Event && dis) {
      var stateListener = function(type) {
        var orig = his[type]
        return function() {
          var rv = orig.apply(this, arguments)
          var event = new Event(type)
          event.arguments = arguments
          dis(event)
          return rv
        }
      }
      his.pushState = stateListener('pushState')
      window.addEventListener('pushState', function() {
        post(true)
      })
    }

    // When in hash mode, we record a pageview based on the onhashchange function
    if (mode === 'hash' && 'onhashchange' in window) {
      window.onhashchange = post
    }

    // Post the page view
    post()

    // Stop when not running on subdomain
    var hostWithoutSubdomain = /\.(.+)/.exec(hostname)[1]
    if (!(host === hostWithoutSubdomain || new RegExp('.' + hostWithoutSubdomain + '$', 'i').test(host))) {
      return warn('Events via this script only work on ' + hostWithoutSubdomain + ' domains')
    }

    // Build a simple queue
    var queue = window[functionName] && window[functionName].q ? window[functionName].q : []

    var loading = false
    var loadIframe = function() {
      loading = true
      var iframe = doc.createElement('iframe')
      iframe.setAttribute('src', uri + '/iframe.html')
      iframe.style.display = 'none'
      iframe.onload = function() {
        var contentWindow = iframe.contentWindow
        var refOrDocRef = ref || cleanRef
        try {
          if (queue) for (var index = 0; index < queue.length; index++) contentWindow.postMessage({ event: queue[index][0], ref: refOrDocRef, campaign: campaign }, targetOrigin)
        } catch(e) { /* Nothing */ }
        window[functionName] = function(event) {
          contentWindow.postMessage({ event: event, ref: refOrDocRef, campaign: campaign }, targetOrigin)
        }
      }
      doc.body.appendChild(iframe)
    }

    // Only load the iframe when events are pushed
    window[functionName] = function() {
      if (!loading) loadIframe()
      queue.push([].slice.call(arguments))
    }

    if (!loading && queue.length) loadIframe()
  } catch (e) {
    warn(e.message)
    var url = uri + '/image.gif'
    if (e.message) url = url + '?error=' + encodeURIComponent(e.message)
    new Image().src = url
  }
})(window, 'simpleanalytics.example.com')