Fix #29: Attempt extraction after parsing is finished, before loading.

src/background/index.js

@@ -53,9 +53,9 @@ import {loadStateFromStorage} from 'commerce/state/sync';
   window.registeredContentScript = browser.contentScripts.register({
     matches: ['<all_urls>'],
     js: [
-      {file: 'product_info.bundle.js'},
+      {file: 'extraction.bundle.js'},
     ],
-    runAt: 'document_idle',
+    runAt: 'document_end',
     allFrames: true,
   });
 

src/extraction/fathom_extraction.js → src/extraction/fathom/index.js

@@ -10,8 +10,8 @@
  * Features: title, image, price
  */
 
-import defaultCoefficients from 'commerce/extraction/fathom_default_coefficients.json';
-import RulesetFactory from 'commerce/extraction/ruleset_factory';
+import defaultCoefficients from 'commerce/extraction/fathom/coefficients.json';
+import RulesetFactory from 'commerce/extraction/fathom/ruleset_factory';
 import {parsePrice} from 'commerce/extraction/utils';
 
 // Minimum score to be considered the "correct" feature element extracted by Fathom

src/extraction/ruleset_factory.js → src/extraction/fathom/ruleset_factory.js

@@ -2,12 +2,6 @@
  * 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/. */
 
-/**
- * Exports a RulesetFactory class, which when instantiated, binds Fathom
- * coefficients to a ruleset. An instance of this class is used for product
- * feature extraction (`fathom_extraction.js`) and for training (`trainees.js`).
- */
-
 import {dom, out, rule, ruleset, score, type} from 'fathom-web';
 // Since the fathom-trainees add-on currently uses a submodule of Fathom, for
 // training, replace 'utils' with 'utilsForFrontend'
@@ -20,11 +14,13 @@ const TOP_BUFFER = 150;
 const ZEROISH = 0.08;
 const ONEISH = 0.9;
 
+/**
+ * Creates Fathom ruleset instances, and holds individual rule methods for
+ * easier testing.
+ */
 export default class RulesetFactory {
   /**
-   * Create a ruleset factory.
-   *
-   * @param {Array.number} coefficients The coefficients to apply for each rule
+   * @param {number[]} coefficients
    */
   constructor(coefficients) {
     [

src/extraction/trainees.js → src/extraction/fathom/trainees.js

@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /* eslint-disable import/no-unresolved */
-import defaultCoefficients from './fathom_default_coefficients.json';
+import defaultCoefficients from './coefficients.json';
 import RulesetFactory from './ruleset_factory';
 
 // Array of numbers corresponding to the coefficients in order
@@ -21,11 +21,10 @@ const coeffs = RulesetFactory.getCoeffsInOrder(defaultCoefficients);
  *
  * How to train:
  *  1. Fork the `mozilla/fathom-trainees` repo,
- *  2. In the `fathom-trainees` add-on, copy this file,
- * `./extraction/fathom_default_coefficients.json` and
- * `./extraction/ruleset_factory.js` to the `./src` folder.
- *    * Note: You will have to replace 'utils' with 'utilsForFrontend' on the
- *      import in `ruleset_factory.js`. See that file for more information.
+ *  2. In the `fathom-trainees` add-on, copy `src/extraction/fathom` to the
+ *     `./src` folder.
+ *     * Note: You will have to replace 'utils' with 'utilsForFrontend' on the
+ *       import in `ruleset_factory.js`. See that file for more information.
  *  3. Follow instructions at: https://github.com/erikrose/fathom-fox#the-trainer.
  *
  * Notes:

src/extraction/index.js

@@ -0,0 +1,86 @@
+/* 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/. */
+
+/**
+ * Content script injected into tabs to attempt extracting information about a
+ * product from the webpage. Set to run at "document_end" after the page has
+ * been parsed but before all resources have been loaded.
+ */
+
+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';
+
+/**
+ * Extraction methods are given the document object for the page, and must
+ * return either a valid ExtractedProduct, or null if a valid product could not
+ * be found.
+ */
+const EXTRACTION_METHODS = [
+  extractProductWithFathom,
+  extractProductWithFallback,
+  extractProductWithOpenGraph,
+];
+
+/**
+ * Perform product extraction, trying each method from EXTRACTION_METHODS in
+ * order until one of them returns a truthy result.
+ * @return {ExtractedProduct|null}
+ */
+function extractProduct() {
+  for (const extract of EXTRACTION_METHODS) {
+    const extractedProduct = extract(window.document);
+    if (extractedProduct) {
+      return extractedProduct;
+    }
+  }
+
+  return null;
+}
+
+/**
+ * Checks to see if any product information for the page was found,
+ * and if so, sends it to the background script.
+ */
+async function attemptExtraction() {
+  const extractedProduct = extractProduct();
+  if (extractedProduct) {
+    await browser.runtime.sendMessage({
+      from: 'content',
+      subject: 'ready',
+      extractedProduct: {
+        ...extractedProduct,
+        url: document.location.href,
+        date: (new Date()).toISOString(),
+      },
+    });
+  }
+}
+
+(async function main() {
+  // If we're in an iframe, don't bother extracting a product EXCEPT if we were
+  // started by the background script for a price check.
+  const isInIframe = window !== window.top;
+  const isBackgroundUpdate = window.location.hash === '#moz-commerce-background';
+  if (isInIframe && !isBackgroundUpdate) {
+    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.
+  const url = new URL(document.location.href);
+  const allowList = await config.get('extractionAllowlist');
+  const allowAll = allowList.length === 1 && allowList[0] === '*';
+  if (!allowAll && !isBackgroundUpdate && !allowList.includes(url.host)) {
+    return;
+  }
+
+  // Extract immediately, and again if the readyState changes.
+  attemptExtraction();
+  document.addEventListener('readystatechange', () => {
+    attemptExtraction();
+  });
+}());

src/extraction/open_graph.js

@@ -0,0 +1,33 @@
+/* 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/. */
+
+/**
+ * Product extraction via Open Graph tags.
+ */
+
+const OPEN_GRAPH_PROPERTY_VALUES = {
+  title: 'og:title',
+  image: 'og:image',
+  price: 'og:price:amount',
+};
+
+/**
+ * Returns any product information available on the page from Open Graph <meta>
+ * tags.
+ */
+export default function extractProduct() {
+  const extractedProduct = {};
+  for (const [feature, propertyValue] of Object.entries(OPEN_GRAPH_PROPERTY_VALUES)) {
+    const metaEle = document.querySelector(`meta[property='${propertyValue}']`);
+
+    // Fail early if any required tags aren't found.
+    if (!metaEle) {
+      return null;
+    }
+
+    extractedProduct[feature] = metaEle.getAttribute('content');
+  }
+
+  return extractedProduct;
+}

src/extraction/fallback_extraction.js → src/extraction/selector/index.js

@@ -10,14 +10,7 @@
 * Features: title, image, price
 */
 
-import extractionData from 'commerce/extraction/fallback_extraction_selectors';
-
-
-const OPEN_GRAPH_PROPERTY_VALUES = {
-  title: 'og:title',
-  image: 'og:image',
-  price: 'og:price:amount',
-};
+import extractionData from 'commerce/extraction/selector/selectors';
 
 /**
  * Returns any extraction data found for the vendor based on the URL
@@ -54,22 +47,23 @@ function findValue(extractors) {
 
 /**
  * Returns any product information available on the page from CSS
- * selectors if they exist, otherwise from Open Graph <meta> tags.
+ * selectors if they exist.
  */
 export default function extractProduct() {
-  const extractedProduct = {};
   const featureInfo = getFeatureInfo();
   if (featureInfo) {
+    const extractedProduct = {};
     for (const [feature, extractors] of Object.entries(featureInfo)) {
-      extractedProduct[feature] = findValue(extractors);
-    }
-  } else {
-    for (const [feature, propertyValue] of Object.entries(OPEN_GRAPH_PROPERTY_VALUES)) {
-      const metaEle = document.querySelector(`meta[property='${propertyValue}']`);
-      if (metaEle) {
-        extractedProduct[feature] = metaEle.getAttribute('content');
+      const featureValue = findValue(extractors);
+      if (!featureValue) {
+        return null;
       }
+
+      extractedProduct[feature] = featureValue;
     }
+
+    return extractedProduct;
   }
-  return extractedProduct;
+
+  return null;
 }

webpack.config.js

@@ -21,7 +21,7 @@ module.exports = {
   target: 'web',
   entry: {
     background: './src/background/index',
-    product_info: './src/product_info',
+    extraction: './src/extraction',
     browser_action: './src/browser_action/index',
   },
   output: {