ga_new_linker.js

/* 2019-02-25
   David Vallejo  ( @ thyng )
   New Google Analytics Linker Parameter Algo
   version 0.1 Needs commenting
   !!! Current version not properly generating the browser fingerprint . As usual the   
   linker value should be only valid for the next 2 minutes since it was generated. 
   Will review it

   Note that GA library currently provides a public function to get the linker param
   google_tag_data.glBridge.generate()
   Use: 
   google_tag_data.glBridge.generate({
        _ga: '121321321321.2315648466',   // Google Analytics GA ID
        _gac: undefined,                  // Google Remarketing ,not needed at all
        _gid: '121321321321.2315648466'   // Google ID
   });
   This glBridge ( Google Linker Bridge ? )tools provides same functionality as GA Linker / Decorate plugin, but
   more likely to be used for All Google Suite products instead of just for Google Analytics
    {
         auto: ƒ, 
         decorate: ƒ, 
         generate: ƒ, 
         get: ƒ
    }

*/

var generateLinkerParam = function(a) {
    // Function to properly grab ID's from Cookies
    var getCookiebyName = function(name) {
        var pair = document.cookie.match(new RegExp(name + '=([^;]+)'));
        return !!pair ? pair[1].match(/GA1\.[0-9]\.(.+)/)[1] : undefined;
    };

    // These are the 3 values used by the new linker
    var cookies = {
        _ga: getCookiebyName("_ga"),
        // Google Analytics GA ID
        _gac: undefined,
        // Google Remarketing
        _gid: getCookiebyName("_gid")// Google ID
    };

    // Calculate current browser_fingerprint based on UA, time, timezone and language
    // 
    var browser_fingerprint = (function(a, b) {
        var F = function(a) {
            // Didnt check what this does, the algo just needs F to be defined. commenting out
            Ne.set(a)
        };
        a = [window.navigator.userAgent, (new Date).getTimezoneOffset(), window.navigator.userLanguage || window.navigator.language, Math.floor((new Date).getTime() / 60 / 1E3) - (void 0 === b ? 0 : b), a].join("*");
        if (!(b = F)) {
            b = Array(256);
            for (var c = 0; 256 > c; c++) {
                for (var d = c, e = 0; 8 > e; e++)
                    d = d & 1 ? d >>> 1 ^ 3988292384 : d >>> 1;
                b[c] = d
            }
        }

        F = b;
        b = 4294967295;
        for (c = 0; c < a.length; c++)
            b = b >>> 8 ^ F[(b ^ a.charCodeAt(c)) & 255];
        return ((b ^ -1) >>> 0).toString(36);
    }
    )();

    // Function to hash the cookie value
    // The following functions takes a string and returns a hash value.
    var hash_cookie_value = function(val) {
        var A, C, D = function(a) {
            A = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_.";
            C = {
                "0": 52,
                "1": 53,
                "2": 54,
                "3": 55,
                "4": 56,
                "5": 57,
                "6": 58,
                "7": 59,
                "8": 60,
                "9": 61,
                "A": 0,
                "B": 1,
                "C": 2,
                "D": 3,
                "E": 4,
                "F": 5,
                "G": 6,
                "H": 7,
                "I": 8,
                "J": 9,
                "K": 10,
                "L": 11,
                "M": 12,
                "N": 13,
                "O": 14,
                "P": 15,
                "Q": 16,
                "R": 17,
                "S": 18,
                "T": 19,
                "U": 20,
                "V": 21,
                "W": 22,
                "X": 23,
                "Y": 24,
                "Z": 25,
                "a": 26,
                "b": 27,
                "c": 28,
                "d": 29,
                "e": 30,
                "f": 31,
                "g": 32,
                "h": 33,
                "i": 34,
                "j": 35,
                "k": 36,
                "l": 37,
                "m": 38,
                "n": 39,
                "o": 40,
                "p": 41,
                "q": 42,
                "r": 43,
                "s": 44,
                "t": 45,
                "u": 46,
                "v": 47,
                "w": 48,
                "x": 49,
                "y": 50,
                "z": 51,
                "-": 62,
                "_": 63,
                ".": 64
            };
            for (var b = [], c = 0; c < a.length; c += 3) {
                var d = c + 1 < a.length
                  , e = c + 2 < a.length
                  , g = a.charCodeAt(c)
                  , f = d ? a.charCodeAt(c + 1) : 0
                  , h = e ? a.charCodeAt(c + 2) : 0
                  , p = g >> 2;
                g = (g & 3) << 4 | f >> 4;
                f = (f & 15) << 2 | h >> 6;
                h &= 63;
                e || (h = 64,
                d || (f = 64));
                b.push(A[p], A[g], A[f], A[h])
            }
            return b.join("")
        };
        return D(String(val));
    };

    // Now we have all the data Let's build the linker String! =)
    // First value is a fixed "1" value, the current GA code does the same. May change in a future
    return ["1", browser_fingerprint, "_ga", hash_cookie_value(cookies._ga), "_gid", hash_cookie_value(cookies._gid)].join('*');
};

var decrypt_cookies_ids = function(a, b) {
        var P = function(a) {
            if (encodeURIComponent instanceof Function) return encodeURIComponent(a);
            F(28);
            return a
        };   
        var m = function(a, b) {
            for (var c in b) b.hasOwnProperty(c) && (a[c] = b[c])
        };
        
        var H = function() {
            var a = {};
            var b = window.google_tag_data;
            window.google_tag_data = void 0 === b ? a : b;
            a = window.google_tag_data;
            b = a.gl;
            b && b.decorators || (b = {
                decorators: []
            }, a.gl = b);
            return b
        };
             
        var c = P(!!b);
        b = H();
        b.data || (b.data = {
            query: {},
            fragment: {}
        }, c(b.data));
        c = {};
        if (b = b.data) m(c, b.query), a && m(c, b.fragment);
        return c
    }

// Example: decrypt_cookies_ids("1*qutsvh*_ga*MTczMjg1NDM3Ni4xNTUwMTAyNDc3*_gid*MTQwMzczNTA1OC4xNTUxMDIzOTA2");