spam-referral-buster

/*!
 * Spam Referrals Buster
 *
 * author: David Vallejo (@thyng)
 * version: 0.2 Beta
 * date: 2015-07-19
 *
 * @link https://www.thyngster.com
 */

(function(){
    var getStrippedDomain = function (url) {
        var a=document.createElement('a');
        a.href=url;
        if (a.hostname.substring(0,4)=="www.") {    
            a.hostname=a.hostname.substring(4,a.hostname.length);
        }
        return a.hostname;
    }
    
    // domain hash routine from urchin.js
    var generateDomainHash =  function generateDomainHash(d)
    {
     if (!d || d=="") return 1;
     var h=0,g=0;
     for (var i=d.length-1;i>=0;i--){
         var c=parseInt(d.charCodeAt(i));
         h=((h << 6) & 0xfffffff) + c + (c << 14);
         if ((g=h & 0xfe00000)!=0) h=(h ^ (g >> 21));
     }
     return h;
    }

    var currentDomain = getStrippedDomain(location.hostname);
    var currentReferrer = getStrippedDomain(document.referrer);
  
    if(currentDomain!=currentReferrer)
    {
      // List of referrals taking from Piwik website
      // https://github.com/piwik/referrer-spam-blacklist (2015-07-19)
      // Domains are hashed to improve performance.
      var blockDomains = [263039757, 34007457, 55065771, 120081032, 26509560, 177333665, 49917920, 179660596, 54583931, 223710155, 262814300, 9477733, 227758541, 180169332, 74254082, 107575378, 156219627, 81867974, 260947933, 241848658, 68743809, 100663633, 259344346, 92805709, 154818280, 66544254, 90401610, 21838571, 180691319, 40491698, 161276909, 228896076, 218653450, 236698258, 199269949, 139910816, 15197733, 212879495, 89031944, 45107895, 156446760, 60097982, 92289550, 23099433, 253356250, 47900916, 193629310, 138291619, 267519837, 28886511, 66298109, 112011863, 132223517, 174536497, 236918930, 146907684, 101321874, 52305723, 210629511, 44250934, 227859215, 239842065, 220961674, 12598181, 177897015, 2834210, 92936079, 257686937, 65584572, 129268638, 194356927, 247275537, 187924413, 180255153, 31164458, 151219372, 11188769, 30110250, 98217802, 127491608, 34343092, 19514413, 26086056, 123546078, 109015895, 269593445, 145229344, 14118499, 157319342, 108747926, 119536157, 170625268, 17197805, 75630209, 202202629, 237263380, 120789660, 241326614, 78112704, 45898739, 34775926, 83705217, 264499608, 226197261, 192682813, 98378696, 25279722, 225216845, 190742972, 68926343, 12888481, 253399839, 211691715, 30357161, 96803849, 174647540, 50565951, 78196482, 117663263, 179948082, 5340074, 239429786, 191908787, 131045142, 247679774, 34656824, 119773649, 53412656, 255172368, 250014942, 82290894, 256272211, 151627489, 163122148, 155788131, 192958581, 259457938, 32766502, 23338722, 106227739, 11385900, 203407945, 170261627, 215481229, 12682925, 52999090, 14939692, 11418542, 57528880, 186878450, 112925470, 33142819, 208158223, 136238764, 250524827, 38514623, 50206266, 155556903, 213518856, 35495229, 132051987, 117297562, 114228379, 240058015, 173866559, 89708551, 4652847, 88425607, 144682409, 76982665, 20660260, 261539474, 26581794, 46480889, 191281652, 99458048, 116177816, 83671944, 39742141, 92111428, 113906054, 178312613, 182536551, 180588710, 138442290, 104487169, 130201486, 203151376, 184532647, 159674236, 140297970, 255970378, 120227657, 215762518, 233644639, 171443617, 268032526, 64260911, 218110746, 106928000, 101061378, 109542662, 214885524, 136675379, 59102766, 140101552, 69930259, 246799110, 179534502, 261660303, 113628933, 190416681, 171884578, 69094803, 203312147, 52522410, 60214959, 260003208, 55348713, 82094420, 232875612, 223271705, 259179784, 10959670, 150111220, 24590584, 256476489, 227512095, 264618125, 260541455, 154056634, 173667361, 91450264, 74558544, 105796289, 106987584, 138748977, 57121832, 109374976, 74068247, 133437067, 157207806, 226943000, 83231635, 180578914, 115705027, 188893231, 265531211, 227914778, 194976682, 5925684, 18074686, 66591913, 66573609, 149298992, 44053282, 8444595, 42906531, 67125655, 194580005, 192774690, 201007782, 235211401, 34498602, 259665032, 209136158, 181346027, 148579321, 246840116, 189388895];
      if(blockDomains.indexOf(generateDomainHash(currentReferrer))>-1)
      {
        // Block using js opt-out
        var property_id = 'UA-XXXXXX-Y';
        window['ga-disable-'+property_id] = true;
        // if you prefer it you can send a push to the dataLayer to block your tags.
        // dataLayer.push({'blockTracking': true});
      }
    }
})();