tools,doc: add Google Analytics tracking.

Adds Google Analytics tracking script to all doc pages when
`DOCS_ANALYTICS` is set when running `make`:

```bash
$ DOCS_ANALYTICS=<GOOGLE ANALYTICS ID> make
```

By default (when `DOCS_ANALYTICS` is not set), no tracking scripts are
included.

It respects "Do Not Track" settings end users might have in their
browser.

Also changes make target `doc-upload` from depending on the
`$(TARBALL)` target, to only depend on `doc` directly.

PR-URL: https://github.com/nodejs/node/pull/6601
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: Rod Vagg <rod@vagg.org>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/doc/api_assets/dnt_helper.js b/doc/api_assets/dnt_helper.js
new file mode 100644
index 00000000000..f255d916c2d
--- /dev/null
+++ b/doc/api_assets/dnt_helper.js
@@ -0,0 +1,49 @@
+/**
+ * http://schalkneethling.github.io/blog/2015/11/06/respect-user-choice-do-not-track/
+ * https://github.com/schalkneethling/dnt-helper/blob/master/js/dnt-helper.js
+ *
+ * Returns true or false based on whether doNotTack is enabled. It also takes into account the
+ * anomalies, such as !bugzilla 887703, which effect versions of Fx 31 and lower. It also handles
+ * IE versions on Windows 7, 8 and 8.1, where the DNT implementation does not honor the spec.
+ * @see https://bugzilla.mozilla.org/show_bug.cgi?id=1217896 for more details
+ * @params {string} [dnt] - An optional mock doNotTrack string to ease unit testing.
+ * @params {string} [userAgent] - An optional mock userAgent string to ease unit testing.
+ * @returns {boolean} true if enabled else false
+ */
+function _dntEnabled(dnt, userAgent) {
+
+    'use strict';
+
+    // for old version of IE we need to use the msDoNotTrack property of navigator
+    // on newer versions, and newer platforms, this is doNotTrack but, on the window object
+    // Safari also exposes the property on the window object.
+    var dntStatus = dnt || navigator.doNotTrack || window.doNotTrack || navigator.msDoNotTrack;
+    var ua = userAgent || navigator.userAgent;
+
+    // List of Windows versions known to not implement DNT according to the standard.
+    var anomalousWinVersions = ['Windows NT 6.1', 'Windows NT 6.2', 'Windows NT 6.3'];
+
+    var fxMatch = ua.match(/Firefox\/(\d+)/);
+    var ieRegEx = /MSIE|Trident/i;
+    var isIE = ieRegEx.test(ua);
+    // Matches from Windows up to the first occurance of ; un-greedily
+    // http://www.regexr.com/3c2el
+    var platform = ua.match(/Windows.+?(?=;)/g);
+
+    // With old versions of IE, DNT did not exist so we simply return false;
+    if (isIE && typeof Array.prototype.indexOf !== 'function') {
+        return false;
+    } else if (fxMatch && parseInt(fxMatch[1], 10) < 32) {
+        // Can't say for sure if it is 1 or 0, due to Fx bug 887703
+        dntStatus = 'Unspecified';
+    } else if (isIE && platform && anomalousWinVersions.indexOf(platform.toString()) !== -1) {
+        // default is on, which does not honor the specification
+        dntStatus = 'Unspecified';
+    } else {
+        // sets dntStatus to Disabled or Enabled based on the value returned by the browser.
+        // If dntStatus is undefined, it will be set to Unspecified
+        dntStatus = { '0': 'Disabled', '1': 'Enabled' }[dntStatus] || 'Unspecified';
+    }
+
+    return dntStatus === 'Enabled' ? true : false;
+}