Add option to disable sending the Do Not Track (DNT) signal

src/_locales/en_US/messages.json

@@ -23,6 +23,10 @@
         "message": "Currently Privacy Badger only checks if third parties are using cookies, HTML5 local storage, or canvas fingerprinting to track your browsing. Some of these domains may be using tracking methods that Privacy Badger can't detect.",
         "description": ""
     },
+    "options_enable_dnt_checkbox": {
+        "message": "Send the <a href='https://www.eff.org/issues/do-not-track' target='_blank'>Do Not Track</a> signal",
+        "description": "Checkbox label for enabling/disabling the Do Not Track signal, found on the general settings page"
+    },
     "options_dnt_policy_setting": {
         "message": "Check if sites comply with EFF's Do Not Track policy",
         "description": "Checkbox label on the general settings page"
@@ -439,4 +443,4 @@
         "message": "Oops. Something went wrong.",
         "description": ""
     }
-}
+}

src/js/background.js

@@ -456,9 +456,10 @@ Badger.prototype = {
     learnInIncognito: false,
     migrationLevel: 0,
     seenComic: false,
+    sendDNTSignal: true,
     showCounter: true,
     showTrackingDomains: false,
-    socialWidgetReplacementEnabled: true,
+    socialWidgetReplacementEnabled: true
   },
 
   /**
@@ -612,6 +613,13 @@ Badger.prototype = {
     return this.getSettings().getItem("socialWidgetReplacementEnabled");
   },
 
+  /**
+   * Check if social widget replacement functionality is enabled
+   */
+  isDNTSignalEnabled: function() {
+    return this.getSettings().getItem("sendDNTSignal");
+  },
+
   isCheckingDNTPolicyEnabled: function() {
     return this.getSettings().getItem("checkForDNTPolicy");
   },

src/js/contentscripts/dnt.js

@@ -64,7 +64,7 @@ if (document instanceof HTMLDocument === false && (
 
 // TODO race condition; fix waiting on https://crbug.com/478183
 chrome.runtime.sendMessage({
-  checkEnabled: true
+  checkDNT: true
 }, function (enabled) {
   if (enabled) {
     insertPageScript(getPageScript());

src/js/options.js

@@ -114,8 +114,10 @@ function loadOptions() {
   $("#show_counter_checkbox").prop("checked", badger.showCounter());
   $("#replace_social_widgets_checkbox").on("click", updateSocialWidgetReplacement);
   $("#replace_social_widgets_checkbox").prop("checked", badger.isSocialWidgetReplacementEnabled());
+  $("#enable_dnt_checkbox").on("click", updateDNTCheckboxClicked);
+  $("#enable_dnt_checkbox").prop("checked", badger.isDNTSignalEnabled());
   $("#check_dnt_policy_checkbox").on("click", updateCheckingDNTPolicy);
-  $("#check_dnt_policy_checkbox").prop("checked", badger.isCheckingDNTPolicyEnabled());
+  $("#check_dnt_policy_checkbox").prop("checked", badger.isCheckingDNTPolicyEnabled()).prop("disabled", !badger.isDNTSignalEnabled());
 
   if (badger.webRTCAvailable) {
     $("#toggle_webrtc_mode").on("click", toggleWebRTCIPProtection);
@@ -316,6 +318,23 @@ function updateSocialWidgetReplacement() {
   });
 }
 
+/**
+ * Update DNT checkbox clicked
+ */
+function updateDNTCheckboxClicked() {
+  const enabled = $("#enable_dnt_checkbox").prop("checked");
+
+  chrome.runtime.sendMessage({
+    type: "updateSettings",
+    data: {
+      sendDNTSignal: enabled
+    }
+  });
+
+  $("#check_dnt_policy_checkbox").prop("checked", enabled).prop("disabled", !enabled);
+  updateCheckingDNTPolicy();
+}
+
 function updateCheckingDNTPolicy() {
   const enabled = $("#check_dnt_policy_checkbox").prop("checked");
 

src/js/webrequest.js

@@ -172,7 +172,9 @@ function onBeforeSendHeaders(details) {
   if (!isThirdPartyDomain(requestDomain, tabDomain)) {
     if (badger.isPrivacyBadgerEnabled(tabDomain)) {
       // Still sending Do Not Track even if HTTP and cookie blocking are disabled
-      details.requestHeaders.push({name: "DNT", value: "1"});
+      if (badger.isDNTSignalEnabled()) {
+        details.requestHeaders.push({name: "DNT", value: "1"});
+      }
       return {requestHeaders: details.requestHeaders};
     } else {
       return {};
@@ -233,13 +235,17 @@ function onBeforeSendHeaders(details) {
     let newHeaders = details.requestHeaders.filter(function (header) {
       return (header.name.toLowerCase() != "cookie" && header.name.toLowerCase() != "referer");
     });
-    newHeaders.push({name: "DNT", value: "1"});
+    if (badger.isDNTSignalEnabled()) {
+      newHeaders.push({name: "DNT", value: "1"});
+    }
     return {requestHeaders: newHeaders};
   }
 
   // if we are here, we're looking at a third party
   // that's not yet blocked or cookieblocked
-  details.requestHeaders.push({name: "DNT", value: "1"});
+  if (badger.isDNTSignalEnabled()) {
+    details.requestHeaders.push({name: "DNT", value: "1"});
+  }
   return {requestHeaders: details.requestHeaders};
 }
 
@@ -776,6 +782,15 @@ function dispatcher(request, sender, sendResponse) {
     badger.storage.getBadgerStorageObject("action_map").deleteItem(request.origin);
 
     sendResponse();
+
+  } else if (request.checkDNT) {
+    // called from contentscripts/dnt.js to check if we should enable it
+    sendResponse(
+      badger.isDNTSignalEnabled()
+      && badger.isPrivacyBadgerEnabled(
+        window.extractHostFromURL(sender.tab.url)
+      )
+    );
   }
 }
 

src/skin/options-layout.css

@@ -91,6 +91,11 @@ button
     margin: 12px 0;
 }
 
+#check_dnt_policy_row {
+  position: relative;
+  left: 25px; 
+}
+
 a, a:hover, a:active, a:visited{
   color: #00aaaa;
   text-decoration: underline;

src/skin/options.html

@@ -151,6 +151,12 @@ <h1><span class="i18n_options_title"></span></h1>
         </label>
       </div>
       <div class="checkbox">
+        <label>
+          <input type="checkbox" id="enable_dnt_checkbox">
+          <span class="i18n_options_enable_dnt_checkbox"></span>
+        </label>
+      </div>
+      <div class="checkbox" id="check_dnt_policy_row">
         <label>
           <input type="checkbox" id="check_dnt_policy_checkbox">
           <span class="i18n_options_dnt_policy_setting"></span>