Merge pull request #168 from mozilla/privacy-controls

 #72: Disable extraction in private browsing sessions.

src/background/price_updates.js

@@ -9,6 +9,7 @@
 
 import config from 'commerce/config';
 import store from 'commerce/state';
+import {shouldUpdatePrices} from 'commerce/privacy';
 import {addPriceFromExtracted, getLatestPriceForProduct} from 'commerce/state/prices';
 import {getAllProducts, getProduct, getProductIdFromExtracted} from 'commerce/state/products';
 
@@ -31,6 +32,10 @@ export function handleWebRequest(details) {
  * Find products that are due for price updates and update them.
  */
 export async function updatePrices() {
+  if (!(await shouldUpdatePrices())) {
+    return;
+  }
+
   const state = store.getState();
   const products = getAllProducts(state);
   const now = new Date();

src/background/telemetry.js

@@ -7,6 +7,8 @@
  * @module
  */
 
+import {shouldCollectTelemetry} from 'commerce/privacy';
+
 const CATEGORY = 'extension.price_alerts';
 
 const EVENTS = {
@@ -156,9 +158,10 @@ export async function registerEvents() {
 }
 
 export async function recordEvent(method, object, value, extra) {
-  if (!browser.telemetry.canUpload()) {
+  if (!browser.telemetry.canUpload() || !(await shouldCollectTelemetry())) {
     return;
   }
+
   await browser.telemetry.recordEvent(
     CATEGORY,
     method,

src/extraction/index.js

@@ -12,6 +12,7 @@ import config from 'commerce/config/content';
 import extractProductWithFathom from 'commerce/extraction/fathom';
 import extractProductWithFallback from 'commerce/extraction/selector';
 import extractProductWithOpenGraph from 'commerce/extraction/open_graph';
+import {shouldExtract} from 'commerce/privacy';
 
 /**
  * Extraction methods are given the document object for the page, and must
@@ -67,6 +68,11 @@ async function attemptExtraction() {
     return;
   }
 
+  // Check privacy settings to determine if we should extract.
+  if (!(await shouldExtract())) {
+    return;
+  }
+
   // Only perform extraction on allowlisted sites. Background updates get a
   // pass; we don't want to accidentally freeze updates for products that are
   // being tracked no matter what.

src/manifest.json

@@ -30,6 +30,7 @@
     "storage",
     "unlimitedStorage",
     "notifications",
+    "privacy",
     "webRequest",
     "webRequestBlocking",
     "telemetry"

src/privacy.js

@@ -0,0 +1,78 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Handles checking privacy settings to gate functionality across the add-on.
+ * @module
+ */
+
+/**
+ * Determine if a content script should extract a product.
+ * @return {boolean}
+ */
+export async function shouldExtract() {
+  return !browser.extension.inIncognitoContext;
+}
+
+/**
+ * Determine if a telemetry event should be recorded
+ * @return {boolean}
+ */
+export async function shouldCollectTelemetry() {
+  if (await trackingProtectionEnabled()) {
+    return false;
+  }
+
+  if (doNotTrackEnabled()) {
+    return false;
+  }
+
+  if (await cookiesBlocked()) {
+    return false;
+  }
+
+  return true;
+}
+
+/**
+ * Determine if a background price update should start
+ * @return {boolean}
+ */
+export async function shouldUpdatePrices() {
+  if (await trackingProtectionEnabled()) {
+    return false;
+  }
+
+  if (doNotTrackEnabled()) {
+    return false;
+  }
+
+  if (await cookiesBlocked()) {
+    return false;
+  }
+
+  return true;
+}
+
+async function trackingProtectionEnabled() {
+  const result = await browser.privacy.websites.trackingProtectionMode.get({});
+  return result.value === 'always';
+}
+
+function doNotTrackEnabled() {
+  return navigator.doNotTrack === '1';
+}
+
+async function cookiesBlocked() {
+  if (browser.privacy.websites.cookieConfig) {
+    const {behavior} = (await browser.privacy.websites.cookieConfig.get({})).value;
+    if (!['allow_all', 'allow_visited'].includes(behavior)) {
+      return true;
+    }
+
+    return false;
+  }
+
+  return true;
+}