gecko-dev/browser/components/pagedata/OpenGraphPageData.jsm

51 строка
1.5 KiB
JavaScript

/* 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/. */
"use strict";
var EXPORTED_SYMBOLS = ["OpenGraphPageData"];
/**
* Collects Open Graph (https://opengraphprotocol.org/) related data from a page.
*/
const OpenGraphPageData = {
/**
* Collects the opengraph data from the page.
*
* @param {Document} document
* The document to collect from
*
* @returns {PageData}
*/
collect(document) {
let pageData = {};
// Sites can technically define an Open Graph prefix other than `og:`.
// However, `og:` is one of the default RDFa prefixes and it's likely
// uncommon that sites use a custom prefix. If we find that metadata is
// missing for common sites due to this issue, we could consider adding a
// basic RDFa parser.
let openGraphTags = document.querySelectorAll("meta[property^='og:'");
for (let tag of openGraphTags) {
// Strip "og:" from the property name.
let propertyName = tag.getAttribute("property").substring(3);
switch (propertyName) {
case "description":
pageData.description = tag.getAttribute("content");
break;
case "site_name":
pageData.siteName = tag.getAttribute("content");
break;
case "image":
pageData.image = tag.getAttribute("content");
break;
}
}
return pageData;
},
};