Piwik现已改名为Matomo,这是一套国外著名的开源网站统计系统,类似于百度统计、Google Analytics等系统。最大的区别就是可以看到其中的源码,这正合我意。因为我一直对统计的系统很好奇,很想知道里面的运行原理是怎么样的,碰巧了解到有这么一个系统,因此马上尝试了一下。国内关于该系统的相关资料比较匮乏,大多是分享怎么安装的,并没有找到有关源码分析的文章。下面先对其做个初步的分析,后面会越来越详细,本人目前的职位是前端,因此会先分析脚本代码,而后再分析后台代码。

一、整体概况

  Piwik的官网是matomo.org,使用PHP编写的,而我以前就是PHP工程师,因此看代码不会有障碍。目前最新版本是3.6,Github地址是matomo-org/matomo,打开地址将会看到下图中的内容(只截取了关键部分)。

  打开js文件夹,里面的piwik.js就是本次要分析的脚本代码(如下图红色框出部分),内容比较多,有7838行代码。

  先把系统的代码都下载下来,然后在本地配置虚拟目录,再开始安装。在安装的时候可以选择语言,该系统支持简体中文(注意下图中红色框出的部分)。系统会执行一些操作(注意看下图左边部分),包括检查当前环境能否安装、建立数据库等,按照提示一步一步来就行,比较简单,没啥难度。

 

  安装完后就会自动跳转到后台界面(如下图所示),有图表,有分析,和常用的统计系统差不多。功能还没细看,只做了初步的了解,界面的友好度还是蛮不错的。

  嵌到页面中的JavaScript代码与其它统计系统也类似,如下所示,也是用异步加载的方式,只是发送的请求地址没有伪装成图像地址(注意看标红的那句代码)。

<script type="text/javascript">
      var _paq = _paq || [];
      /* tracker methods like "setCustomDimension" should be called before "trackPageView" */
      _paq.push(['trackPageView']);
      _paq.push(['enableLinkTracking']);
      (function() {
        var u="//loc.piwik.cn/";    //自定义
        _paq.push(['setTrackerUrl', u+'piwik.php']);
        _paq.push(['setSiteId', '1']);
        var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0];
        g.type='text/javascript'; g.async=true; g.defer=true; g.src='piwik.js'; s.parentNode.insertBefore(g,s);
      })();
</script>

  在页面中嵌入这段脚本后,页面在刷新的时候,会有下图中的请求。在请求中带了一大堆的参数,在后面的内容中会对每个参数做释义。

二、脚本拆分

  7000多行的脚本,当然不能一行一行的读,需要先拆分,拆成一个一个的模块,然后再逐个分析。脚本之所以这么大,是因为里面编写了大量代码来兼容各个版本的浏览器,这其中甚至包括IE4、Firefox1.0、Netscape等骨灰级的浏览器。接下来我把源码拆分成6个部分,分别是json、private、query、content-overlay、tracker和piwik,如下图红线框出的所示,piwik-all中包含了全部代码,便于对比。代码已上传到Github

  json.js是一个开源插件JSON3,为了兼容不支持JSON对象的浏览器而设计的,这里面的代码可以单独研究。private.js包含了一些用于全局的私有变量和私有函数,例如定义系统对象的别名、判断类型等。query.js中包含了很多操作HTML元素的方法,例如设置元素属性、查询某个CSS类的元素等,它类似于一个微型的jQuery库,不过有许多独特的功能。content-overlay.js有两部分组成,一部分包含内容追踪以及URL拼接等功能,另一部分是用来处理嵌套的页面,这里面具体没有细看。tracker.js中只有一个Tracker()函数,不过内容最多,有4700多行,主要的统计逻辑都在这里了。piwik.js中内容不多,包含一些初始化和插件的钩子等功能,钩子具体怎么运作的还没细看。
  虽然分成了6部分,但是各部分的内容还是蛮多的,并且内容之间是有联系的,因此短时间的话,很难搞清楚其中所有的门道。我就挑了一点我个人感觉最重要的先做分析。

1)3种传送数据的方式

  我原先只知道两种传送数据的方式,一种是通过Ajax的方式,另一种是创建一个Image对象,然后为其定义src属性,数据作为URL的参数传递给后台,这种方式很通用,并且还能完美解决跨域问题。我以前编写的一个性能参数搜集的插件primus.js,也是这么传送数据的。在阅读源码的时候,发现了第三种传送数据的方式,使用Navigator对象的sendBeacon()
  MDN上说:“此方法可用于通过HTTP将少量数据异步传输到Web服务器”。虽然这个方法有兼容问题,但我还是被震撼到了。它很适合统计的场景,MDN上又讲到:“统计代码会在页面关闭(window.onunload)之前向web服务器发送数据,但过早的发送数据可能错过收集数据的机会。然而, 要保证在页面关闭期间发送数据一直比较困难,因为浏览器通常会忽略在卸载事件中产生的异步请求 。在使用sendBeacon()方法后,能使浏览器在有机会时异步地向服务器发送数据,同时不会延迟页面的卸载或影响下一页的载入。这就解决了提交分析数据时的所有的问题:使它可靠,异步并且不会影响下一页面的加载,并且代码更简单”。下面是代码片段(注意看标红的那句代码),存在于tracker.js中。

function sendPostRequestViaSendBeacon(request) {
  var supportsSendBeacon =
    "object" === typeof navigatorAlias &&
    "function" === typeof navigatorAlias.sendBeacon &&
    "function" === typeof Blob;
  if (!supportsSendBeacon) {
    return false;
  }
  var headers = {
    type: "application/x-www-form-urlencoded; charset=UTF-8"
  };
  var success = false;
  try {
    var blob = new Blob([request], headers);
    success = navigatorAlias.sendBeacon(configTrackerUrl, blob);
    // returns true if the user agent is able to successfully queue the data for transfer,
    // Otherwise it returns false and we need to try the regular way
  } catch (e) {
    return false;
  }
  return success;
}

2)参数释义

  下面的方法(存在于tracker.js中)专门用于搜集页面中的统计数据,将它们拼接成指定链接的参数,而这条链接中的参数最终将会发送给服务器。

/**
 * Returns the URL to call piwik.php,
 * with the standard parameters (plugins, resolution, url, referrer, etc.).
 * Sends the pageview and browser settings with every request in case of race conditions.
 */
function getRequest(request, customData, pluginMethod, currentEcommerceOrderTs) {
  var i,
    now = new Date(),
    nowTs = Math.round(now.getTime() / 1000),
    referralTs,
    referralUrl,
    referralUrlMaxLength = 1024,
    currentReferrerHostName,
    originalReferrerHostName,
    customVariablesCopy = customVariables,
    cookieSessionName = getCookieName("ses"),
    cookieReferrerName = getCookieName("ref"),
    cookieCustomVariablesName = getCookieName("cvar"),
    cookieSessionValue = getCookie(cookieSessionName),
    attributionCookie = loadReferrerAttributionCookie(),
    currentUrl = configCustomUrl || locationHrefAlias,
    campaignNameDetected,
    campaignKeywordDetected;

  if (configCookiesDisabled) {
    deleteCookies();
  }

  if (configDoNotTrack) {
    return "";
  }

  var cookieVisitorIdValues = getValuesFromVisitorIdCookie();
  if (!isDefined(currentEcommerceOrderTs)) {
    currentEcommerceOrderTs = "";
  }

  // send charset if document charset is not utf-8. sometimes encoding
  // of urls will be the same as this and not utf-8, which will cause problems
  // do not send charset if it is utf8 since it's assumed by default in Piwik
  var charSet = documentAlias.characterSet || documentAlias.charset;

  if (!charSet || charSet.toLowerCase() === "utf-8") {
    charSet = null;
  }

  campaignNameDetected = attributionCookie[0];
  campaignKeywordDetected = attributionCookie[1];
  referralTs = attributionCookie[2];
  referralUrl = attributionCookie[3];

  if (!cookieSessionValue) {
    // cookie 'ses' was not found: we consider this the start of a 'session'

    // here we make sure that if 'ses' cookie is deleted few times within the visit
    // and so this code path is triggered many times for one visit,
    // we only increase visitCount once per Visit window (default 30min)
    var visitDuration = configSessionCookieTimeout / 1000;
    if (
      !cookieVisitorIdValues.lastVisitTs ||
      nowTs - cookieVisitorIdValues.lastVisitTs > visitDuration
    ) {
      cookieVisitorIdValues.visitCount++;
      cookieVisitorIdValues.lastVisitTs = cookieVisitorIdValues.currentVisitTs;
    }

    // Detect the campaign information from the current URL
    // Only if campaign wasn't previously set
    // Or if it was set but we must attribute to the most recent one
    // Note: we are working on the currentUrl before purify() since we can parse the campaign parameters in the hash tag
    if (
      !configConversionAttributionFirstReferrer ||
      !campaignNameDetected.length
    ) {
      for (i in configCampaignNameParameters) {
        if (
          Object.prototype.hasOwnProperty.call(configCampaignNameParameters, i)
        ) {
          campaignNameDetected = getUrlParameter(
            currentUrl,
            configCampaignNameParameters[i]
          );

          if (campaignNameDetected.length) {
            break;
          }
        }
      }

      for (i in configCampaignKeywordParameters) {
        if (
          Object.prototype.hasOwnProperty.call(
            configCampaignKeywordParameters,
            i
          )
        ) {
          campaignKeywordDetected = getUrlParameter(
            currentUrl,
            configCampaignKeywordParameters[i]
          );

          if (campaignKeywordDetected.length) {
            break;
          }
        }
      }
    }

    // Store the referrer URL and time in the cookie;
    // referral URL depends on the first or last referrer attribution
    currentReferrerHostName = getHostName(configReferrerUrl);
    originalReferrerHostName = referralUrl.length
      ? getHostName(referralUrl)
      : "";

    if (
      currentReferrerHostName.length && // there is a referrer
      !isSiteHostName(currentReferrerHostName) && // domain is not the current domain
      (!configConversionAttributionFirstReferrer || // attribute to last known referrer
      !originalReferrerHostName.length || // previously empty
        isSiteHostName(originalReferrerHostName))
    ) {
      // previously set but in current domain
      referralUrl = configReferrerUrl;
    }

    // Set the referral cookie if we have either a Referrer URL, or detected a Campaign (or both)
    if (referralUrl.length || campaignNameDetected.length) {
      referralTs = nowTs;
      attributionCookie = [
        campaignNameDetected,
        campaignKeywordDetected,
        referralTs,
        purify(referralUrl.slice(0, referralUrlMaxLength))
      ];

      setCookie(
        cookieReferrerName,
        JSON_PIWIK.stringify(attributionCookie),
        configReferralCookieTimeout,
        configCookiePath,
        configCookieDomain
      );
    }
  }

  // build out the rest of the request
  request +=
    "&idsite=" +
    configTrackerSiteId +
    "&rec=1" +
    "&r=" +
    String(Math.random()).slice(2, 8) + // keep the string to a minimum
    "&h=" +
    now.getHours() +
    "&m=" +
    now.getMinutes() +
    "&s=" +
    now.getSeconds() +
    "&url=" +
    encodeWrapper(purify(currentUrl)) +
    (configReferrerUrl.length
      ? "&urlref=" + encodeWrapper(purify(configReferrerUrl))
      : "") +
    (configUserId && configUserId.length
      ? "&uid=" + encodeWrapper(configUserId)
      : "") +
    "&_id=" +
    cookieVisitorIdValues.uuid +
    "&_idts=" +
    cookieVisitorIdValues.createTs +
    "&_idvc=" +
    cookieVisitorIdValues.visitCount +
    "&_idn=" +
    cookieVisitorIdValues.newVisitor + // currently unused
    (campaignNameDetected.length
      ? "&_rcn=" + encodeWrapper(campaignNameDetected)
      : "") +
    (campaignKeywordDetected.length
      ? "&_rck=" + encodeWrapper(campaignKeywordDetected)
      : "") +
    "&_refts=" +
    referralTs +
    "&_viewts=" +
    cookieVisitorIdValues.lastVisitTs +
    (String(cookieVisitorIdValues.lastEcommerceOrderTs).length
      ? "&_ects=" + cookieVisitorIdValues.lastEcommerceOrderTs
      : "") +
    (String(referralUrl).length
      ? "&_ref=" +
        encodeWrapper(purify(referralUrl.slice(0, referralUrlMaxLength)))
      : "") +
    (charSet ? "&cs=" + encodeWrapper(charSet) : "") +
    "&send_image=0";

  // browser features
  for (i in browserFeatures) {
    if (Object.prototype.hasOwnProperty.call(browserFeatures, i)) {
      request += "&" + i + "=" + browserFeatures[i];
    }
  }

  var customDimensionIdsAlreadyHandled = [];
  if (customData) {
    for (i in customData) {
      if (
        Object.prototype.hasOwnProperty.call(customData, i) &&
        /^dimension\d+$/.test(i)
      ) {
        var index = i.replace("dimension", "");
        customDimensionIdsAlreadyHandled.push(parseInt(index, 10));
        customDimensionIdsAlreadyHandled.push(String(index));
        request += "&" + i + "=" + customData[i];
        delete customData[i];
      }
    }
  }

  if (customData && isObjectEmpty(customData)) {
    customData = null;
    // we deleted all keys from custom data
  }

  // custom dimensions
  for (i in customDimensions) {
    if (Object.prototype.hasOwnProperty.call(customDimensions, i)) {
      var isNotSetYet =
        -1 === indexOfArray(customDimensionIdsAlreadyHandled, i);
      if (isNotSetYet) {
        request += "&dimension" + i + "=" + customDimensions[i];
      }
    }
  }

  // custom data
  if (customData) {
    request += "&data=" + encodeWrapper(JSON_PIWIK.stringify(customData));
  } else if (configCustomData) {
    request += "&data=" + encodeWrapper(JSON_PIWIK.stringify(configCustomData));
  }

  // Custom Variables, scope "page"
  function appendCustomVariablesToRequest(customVariables, parameterName) {
    var customVariablesStringified = JSON_PIWIK.stringify(customVariables);
    if (customVariablesStringified.length > 2) {
      return (
        "&" + parameterName + "=" + encodeWrapper(customVariablesStringified)
      );
    }
    return "";
  }

  var sortedCustomVarPage = sortObjectByKeys(customVariablesPage);
  var sortedCustomVarEvent = sortObjectByKeys(customVariablesEvent);

  request += appendCustomVariablesToRequest(sortedCustomVarPage, "cvar");
  request += appendCustomVariablesToRequest(sortedCustomVarEvent, "e_cvar");

  // Custom Variables, scope "visit"
  if (customVariables) {
    request += appendCustomVariablesToRequest(customVariables, "_cvar");

    // Don't save deleted custom variables in the cookie
    for (i in customVariablesCopy) {
      if (Object.prototype.hasOwnProperty.call(customVariablesCopy, i)) {
        if (customVariables[i][0] === "" || customVariables[i][1] === "") {
          delete customVariables[i];
        }
      }
    }

    if (configStoreCustomVariablesInCookie) {
      setCookie(
        cookieCustomVariablesName,
        JSON_PIWIK.stringify(customVariables),
        configSessionCookieTimeout,
        configCookiePath,
        configCookieDomain
      );
    }
  }

  // performance tracking
  if (configPerformanceTrackingEnabled) {
    if (configPerformanceGenerationTime) {
      request += "&gt_ms=" + configPerformanceGenerationTime;
    } else if (
      performanceAlias &&
      performanceAlias.timing &&
      performanceAlias.timing.requestStart &&
      performanceAlias.timing.responseEnd
    ) {
      request +=
        "&gt_ms=" +
        (performanceAlias.timing.responseEnd -
          performanceAlias.timing.requestStart);
    }
  }

  if (configIdPageView) {
    request += "&pv_id=" + configIdPageView;
  }

  // update cookies
  cookieVisitorIdValues.lastEcommerceOrderTs =
    isDefined(currentEcommerceOrderTs) && String(currentEcommerceOrderTs).length
      ? currentEcommerceOrderTs
      : cookieVisitorIdValues.lastEcommerceOrderTs;
  setVisitorIdCookie(cookieVisitorIdValues);
  setSessionCookie();

  // tracker plugin hook
  request += executePluginMethod(pluginMethod, {
    tracker: trackerInstance,
    request: request
  });

  if (configAppendToTrackingUrl.length) {
    request += "&" + configAppendToTrackingUrl;
  }

  if (isFunction(configCustomRequestContentProcessing)) {
    request = configCustomRequestContentProcessing(request);
  }

  return request;
}

  统计代码每次都会传送数据,而每次请求都会带上一大串的参数,这些参数都是简写,下面做个简单说明(如有不正确的地方,欢迎指正),部分参数还没作出合适的解释,例如UUID的生成规则等。首先将这些参数分为两部分,第一部分如下所列:
1、idsite:网站ID
2、rec:1(写死)
3、r:随机码
4、h:当前小时
5、m:当前分钟
6、s:当前秒数
7、url:当前纯净地址,只留域名和协议
8、_id:UUID
9、_idts:访问的时间戳
10、_idvc:访问数
11、_idn:新访客(目前尚未使用)
12、_refts:访问来源的时间戳
13、_viewts:上一次访问的时间戳
14、cs:当前页面的字符编码
15、send_image:是否用图像请求方式传输数据
16、gt_ms:内容加载消耗的时间(响应结束时间减去请求开始时间)
17、pv_id:唯一性标识
  再列出第二部分,用于统计浏览器的功能,通过Navigator对象的属性(mimeTypes、javaEnabled等)和Screen对象的属性(width与height)获得。
1、pdf:是否支持pdf文件类型
2、qt:是否支持QuickTime Player播放器
3、realp:是否支持RealPlayer播放器
4、wma:是否支持MPlayer播放器
5、dir:是否支持Macromedia Director
6、fla:是否支持Adobe FlashPlayer
7、java:是否激活了Java
8、gears:是否安装了Google Gears
9、ag:是否安装了Microsoft Silverlight
10、cookie:是否启用了Cookie
11、res:屏幕的宽和高(未正确计算高清显示器)
  上面这11个参数的获取代码,可以参考下面这个方法(同样存在于tracker.js中),注意看代码中的pluginMap变量(已标红),它保存了多个MIME类型,用来检测是否安装或启用了指定的插件或功能。

/*
* Browser features (plugins, resolution, cookies)
*/
function detectBrowserFeatures() {
  var i,
    mimeType,
    pluginMap = {
      // document types
      pdf: "application/pdf",

      // media players
      qt: "video/quicktime",
      realp: "audio/x-pn-realaudio-plugin",
      wma: "application/x-mplayer2",

      // interactive multimedia
      dir: "application/x-director",
      fla: "application/x-shockwave-flash",

      // RIA
      java: "application/x-java-vm",
      gears: "application/x-googlegears",
      ag: "application/x-silverlight"
    };

  // detect browser features except IE < 11 (IE 11 user agent is no longer MSIE)
  if (!new RegExp("MSIE").test(navigatorAlias.userAgent)) {
    // general plugin detection
    if (navigatorAlias.mimeTypes && navigatorAlias.mimeTypes.length) {
      for (i in pluginMap) {
        if (Object.prototype.hasOwnProperty.call(pluginMap, i)) {
          mimeType = navigatorAlias.mimeTypes[pluginMap[i]];
          browserFeatures[i] = mimeType && mimeType.enabledPlugin ? "1" : "0";
        }
      }
    }

    // Safari and Opera
    // IE6/IE7 navigator.javaEnabled can't be aliased, so test directly
    // on Edge navigator.javaEnabled() always returns `true`, so ignore it
    if (
      !new RegExp("Edge[ /](\\d+[\\.\\d]+)").test(navigatorAlias.userAgent) &&
      typeof navigator.javaEnabled !== "unknown" &&
      isDefined(navigatorAlias.javaEnabled) &&
      navigatorAlias.javaEnabled()
    ) {
      browserFeatures.java = "1";
    }

    // Firefox
    if (isFunction(windowAlias.GearsFactory)) {
      browserFeatures.gears = "1";
    }

    // other browser features
    browserFeatures.cookie = hasCookies();
  }

  var width = parseInt(screenAlias.width, 10);
  var height = parseInt(screenAlias.height, 10);
  browserFeatures.res = parseInt(width, 10) + "x" + parseInt(height, 10);
}

  除了上述20多个参数之外,在系统官网上可点击“Tracking HTTP API”查看到所有的参数,只不过都是英文的。 

上面用到的代码已上传至https://github.com/pwstrick/mypiwik,如有需要,可自行下载。

Last modification:February 10th, 2020 at 10:02 pm