addons/firefox-addons/feed-preview: js/background.js comparison

comparison js/background.js @ 54:ede87e1004f9

Fix issues with feed detection Query the feed probe content script for available feeds from the background script instead of making the content script message the background script. This solves a race condition between the message from the content script sending any feeds associated with the current document and the tab's status "complete" event signaling that a new document has been loaded and hiding the page action. Sometimes that event would be triggered after the message from the content script and thus hide the page action again. In addition, navigating back to a previously visited page might not cause a reload which means that the content script would not send a message if there were feeds associated with the current document.

author	Guido Berhoerster <guido+feed-preview@berhoerster.name>
date	Thu, 26 Sep 2019 23:11:18 +0200
parents	586eebf8efb7
children	fc5fca9af05f

comparison

equal deleted inserted replaced

-:7e1a2357b8c5
+:ede87e1004f9
 },
 {urls: ['http://*/*', 'https://*/*'], types: ['main_frame']},
 ['blocking', 'responseHeaders']);
 browser.runtime.onMessage.addListener((request, sender, sendResponse) => {
-let tab = sender.tab;
+// popup querying feeds
-if (typeof tab !== 'undefined') {
+sendResponse(tabsFeeds.get(request));
-// content script sending feeds
+});
-tabsFeeds.set(tab.id, request);
-browser.pageAction.show(tab.id);
+browser.tabs.onUpdated.addListener(async (tabId, changeInfo, tab) => {
-} else {
-// popup querying feeds
-sendResponse(tabsFeeds.get(request));
-}
-});
-browser.tabs.onUpdated.addListener((tabId, changeInfo, tab) => {
 if (changeInfo.status !== 'complete') {
+// hide the page action when the URL changes since it is no longer
+// valid, it will be shown again if the content script detects a feed
+browser.pageAction.hide(tabId);
 return;
 }
-// hide the page action when the URL changes since it is no longer valid,
-// it will be shown again if the content script detects a feed
-browser.pageAction.hide(tabId);
-// inject content script once if the requested URL is a feed preview
 if (tabsFeedPreviews.get(tabId) === tab.url) {
+// inject content script once if the requested URL is a feed preview
 browser.tabs.executeScript(tabId, {
 file: 'content_scripts/feed-readers.js'
 });
 tabsFeedPreviews.delete(tabId);
+} else {
+// query available feeds
+let feeds = await browser.tabs.sendMessage(tabId, {});
+if (feeds.length > 0) {
+tabsFeeds.set(tabId, feeds);
+browser.pageAction.show(tabId);
+console.log(`detected feeds in tab ${tabId} for ${tab.url}:\n`,
+feeds);
+} else {
+console.log(`no feeds detected in tab ${tabId} for ${tab.url}\n`);
+}
 }
 }, {properties: ["status"]});
 browser.tabs.onRemoved.addListener((tabId, removeInfo) => {
 tabsFeeds.delete(tabId);
 if (typeof feedPreview !== 'undefined' &&
 feedPreview === Object(feedPreview)) {
 feedPreviewOptions.expandEntries = !!feedPreview.expandEntries;
 }
 });
 browser.storage.onChanged.addListener((changes, areaName) => {
 if (areaName !== 'sync' || typeof changes.feedPreview === 'undefined') {
 return;
 }