推荐订阅源

　　当我们在Taptap上访问某款游戏时，比如https://www.taptap.com/app/34762，taptap会记录下这次访问，它是怎么做的呢。

　　首先，用记事本打开这个网址，在head部分看到下面这行引用，继续打开这个js

          <script type="text/javascript" src="https://static.taptapdada.com/scripts/tracker.js" async></script>          

(function (window, document) {
    function createHttpRequest() {
        if (window.ActiveXObject) {
            return new ActiveXObject("Microsoft.XMLHTTP");
        }
        else if (window.XMLHttpRequest) {
            return new XMLHttpRequest();
        }
    }

    function LogTracker(host, project, logstore) {
        this.uri_ = 'https://' + project + '.' + host + '/logstores/' + logstore + '/track?APIVersion=0.6.0';
        this.params_ = [];
        this.httpRequest_ = createHttpRequest();
    }

    LogTracker.prototype = {
        push: function (key, value) {
            if (!key || !value) {
                return;
            }
            this.params_.push(key);
            this.params_.push(value);
        },
        logger: function () {
            var url = this.uri_;
            var k = 0;
            while (this.params_.length > 0) {
                if (k % 2 == 0) {
                    url += '&' + encodeURIComponent(this.params_.shift());
                }
                else {
                    url += '=' + encodeURIComponent(this.params_.shift());
                }
                ++k;
            }
            try {
                this.httpRequest_.open("GET", url, true);
                this.httpRequest_.send(null);
            }
            catch (ex) {
                if (window && window.console && typeof window.console.log === 'function') {
                    console.log("Failed to log to log service because of this exception:\n" + ex);
                    console.log("Failed log data:", url);
                }
            }

        }
    };
    window.Tracker = LogTracker;
})(window, document);

这里定义了LogTracker这样日志跟踪类，并提供了参数供调用方填写，回到之前的html代码，寻找这个类调用的地方

    <script>
        $(function () {
            var logger = new window.Tracker('cn-beijing.log.aliyuncs.com', 'tap-snow', 'logs');
            logger.push('platform', 'web');
            logger.push('device', navigator.userAgent);
            logger.push('type', 'pageView');
            logger.push('paramUrl', 'https://www.taptap.com/app/34762');
            logger.push('paramReferer', document.referrer);
            logger.logger();
        });
    </script>

这里看到页面访问时，会访问 https://tap-snow.cn-beijing.log.aliyuncs.com/logstores/logs/track?APIVersion=0.6.0&platform=web&device=...