GoogleChrome · brendankenny · Dec 1, 2016 · Nov 28, 2016 · Nov 28, 2016 · Nov 28, 2016
diff --git a/lighthouse-cli/test/fixtures/dobetterweb/dbw_tester.html b/lighthouse-cli/test/fixtures/dobetterweb/dbw_tester.html
@@ -221,6 +221,12 @@ <h2>Do better web tester page</h2>
   });
 }
 
+function notificationOnStartTest() {
+  Notification.requestPermission().then(function () {
+    // noop
+  });
+}
+
 function oldCSSFlexboxTest() {
   stampTemplate('old-flexbox-tmpl', document.body);
 }
@@ -243,6 +249,7 @@ <h2>Do better web tester page</h2>
   mutationEvenTest();
   passiveEventsListenerTest();
   geolocationOnStartTest();
+  notificationOnStartTest();
   linksBlockingFirstPaintTest();
   noRelOpenLinksTest();
   oldCSSFlexboxTest();
@@ -268,6 +275,9 @@ <h2>Do better web tester page</h2>
   if (params.has('geolocation')) {
     geolocationOnStartTest();
   }
+  if (params.has('notifications')) {
+    notificationOnStartTest();
+  }
   if (params.has('linksblockfp')) {
     linksBlockingFirstPaintTest();
   }

diff --git a/lighthouse-cli/test/smokehouse/dobetterweb/dbw-expectations.js b/lighthouse-cli/test/smokehouse/dobetterweb/dbw-expectations.js
@@ -36,6 +36,7 @@ module.exports = [
       'no-mutation-events': false,
       'no-old-flexbox': false,
       'no-websql': false,
+      'notification-on-start': false,
       'script-blocking-first-paint': false,
       'uses-passive-event-listeners': false
     }

diff --git a/lighthouse-core/audits/dobetterweb/notification-on-start.js b/lighthouse-core/audits/dobetterweb/notification-on-start.js
@@ -0,0 +1,80 @@
+/**
+ * @license
+ * Copyright 2016 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Audits a page to see if it is requesting usage of the notification API on
+ * page load. This is often a sign of poor user experience because it lacks context.
+ */
+
+'use strict';
+
+const Audit = require('../audit');
+const Formatter = require('../../formatters/formatter');
+
+class NotificationOnStart extends Audit {
+  /**
+   * @return {!AuditMeta}
+   */
+  static get meta() {
+    return {
+      category: 'UX',
+      name: 'notification-on-start',
+      description: 'Page does not automatically request notification permissions on page load',
+      helpText: 'Using notifications without context is a poor user experience. Always tie API ' +
+                'permissions to user interactions.',
+      requiredArtifacts: ['NotificationOnStart']
+    };
+  }
+
+  /**
+   * @param {!Artifacts} artifacts
+   * @return {!AuditResult}
+   */
+  static audit(artifacts) {
+    if (typeof artifacts.NotificationOnStart === 'undefined' ||
+        artifacts.NotificationOnStart.value === -1) {
+      let debugString = 'Unknown error with the NotificationOnStart gatherer';
+      if (typeof artifacts.NotificationOnStart === 'undefined') {
+        debugString = 'NotificationOnStart gatherer did not run';
+      } else if (artifacts.NotificationOnStart.debugString) {
+        debugString = artifacts.NotificationOnStart.debugString;
+      }
+
+      return NotificationOnStart.generateAuditResult({
+        rawValue: -1,
+        debugString
+      });
+    }
+
+    const results = artifacts.NotificationOnStart.usage.map(err => {
+      return Object.assign({
+        label: `line: ${err.line}, col: ${err.col}`
+      }, err);
+    });
+
+    return NotificationOnStart.generateAuditResult({
+      rawValue: results.length === 0,
+      extendedInfo: {
+        formatter: Formatter.SUPPORTED_FORMATS.URLLIST,
+        value: results
+      }
+    });
+  }
+
+}
+
+module.exports = NotificationOnStart;
diff --git a/lighthouse-core/config/default.json b/lighthouse-core/config/default.json
@@ -37,6 +37,7 @@
       "dobetterweb/datenow",
       "dobetterweb/document-write",
       "dobetterweb/geolocation-on-start",
+      "dobetterweb/notification-on-start",
       "dobetterweb/tags-blocking-first-paint",
       "dobetterweb/websql"
     ]
@@ -84,6 +85,7 @@
     "dobetterweb/no-mutation-events",
     "dobetterweb/no-old-flexbox",
     "dobetterweb/no-websql",
+    "dobetterweb/notification-on-start",
     "dobetterweb/script-blocking-first-paint",
     "dobetterweb/uses-http2",
     "dobetterweb/uses-passive-event-listeners"
@@ -320,6 +322,9 @@
         },
         "geolocation-on-start": {
           "expectedValue": false
+        },
+        "notification-on-start": {
+          "expectedValue": false
         }
       }
     }, {

diff --git a/lighthouse-core/gather/gatherers/dobetterweb/notification-on-start.js b/lighthouse-core/gather/gatherers/dobetterweb/notification-on-start.js
@@ -0,0 +1,67 @@
+/**
+ * @license
+ * Copyright 2016 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Captures calls to the notification API on page load.
+ */
+
+'use strict';
+
+const Gatherer = require('../gatherer');
+
+/* global navigator */
+
+/* istanbul ignore next */
+function queryNotificationPermission() {
+  return navigator.permissions.query({name: 'notifications'}).then(result => {
+    return result.state;
+  });
+}
+
+class NotificationOnStart extends Gatherer {
+
+  beforePass(options) {
+    this.collectNotificationUsage = options.driver.captureFunctionCallSites(
+        'Notification.requestPermission');
+  }
+
+  afterPass(options) {
+    return options.driver.evaluateAsync(`(${queryNotificationPermission.toString()}())`)
+        .then(state => {
+          if (state === 'granted' || state === 'denied') {
+            this.artifact = {
+              value: -1,
+              debugString: 'Unable to determine if this permission was requested ' +
+                           'on page load because it had already been set. ' +
+                           'Try resetting the permission and run Lighthouse again.'
+            };
+            return;
+          }
+
+          return this.collectNotificationUsage().then(results => {
+            this.artifact.usage = results;
+          });
+        }).catch(err => {
+          this.artifact = {
+            value: -1,
+            debugString: err && err.toString()
+          };
+        });
+  }
+}
+
+module.exports = NotificationOnStart;