Incorporate custom update notifier for all apps

Former-commit-id: a81d4282f81cae221ec27576e4ee6b5971481ade [formerly 2d0dc3ef5a0e5d014c14438f767e7742cbcecb7c [formerly 81710ec0493e9f2727baa8bc2eeaa3511229a232]]
Former-commit-id: 751684742a550c7d8ca5e057390df773d27cab24 [formerly 2652298d2a974e213cbf899f1140b3dd1938aa89]
Former-commit-id: d622327206178622525a611667bec2acc7761e56

www/index.html

@@ -738,7 +738,7 @@
                                     <label class="checkbox">
                                         <input type="checkbox" name="allowInternetAccess" id="allowInternetAccessCheck">
                                         <span class="checkmark"></span>
-                                        <b>Allow Internet access?</b>
+                                        <b>Allow Internet access?</b> <span id="updateStatus">(and check for updates)</span>
                                     </label>
                                 </div>
                                 <div id="downloadLinks" style="display: none;"></div>

www/js/app.js

@@ -26,8 +26,8 @@
 // This uses require.js to structure javascript:
 // http://requirejs.org/docs/api.html#define
 
-define(['jquery', 'zimArchiveLoader', 'uiUtil', 'util', 'utf8', 'cache', 'images', 'settingsStore', 'transformStyles', 'kiwixServe'],
+define(['jquery', 'zimArchiveLoader', 'uiUtil', 'util', 'utf8', 'cache', 'images', 'settingsStore', 'transformStyles', 'kiwixServe', 'updater'],
-    function ($, zimArchiveLoader, uiUtil, util, utf8, cache, images, settingsStore, transformStyles, kiwixServe) {
+    function ($, zimArchiveLoader, uiUtil, util, utf8, cache, images, settingsStore, transformStyles, kiwixServe, updater) {
 
         /**
          * The delay (in milliseconds) between two "keepalive" messages
@@ -866,6 +866,27 @@ define(['jquery', 'zimArchiveLoader', 'uiUtil', 'util', 'utf8', 'cache', 'images
             });
         }
 
+        // Check for GitHub updates
+        function checkUpdateServer() {
+            if (!params.allowInternetAccess) {
+                console.log("The update check was blocked because the user has not allowed Internet access.")
+                return;
+            }
+            updater.getLatestUpdates(function (tag, url, releases) {
+                var updateSpan = document.getElementById('updateStatus');
+                if (!tag) {
+                    updateSpan.innerHTML = '[ <b><i>App is up to date</i></b> ]';
+                    console.log('No new update was found.');
+                    return;
+                }
+                console.log('We found this update: [' + tag + '] ' + url, releases);
+                updateSpan.innerHTML = '[ <b><i><a href="#alertBoxPersistent">New update!</a></i></b> ]';
+                uiUtil.showUpgradeReady(tag.replace(/^v/, ''), 'download', url);
+            });
+        }
+        // Do check on startup
+        setTimeout(checkUpdateServer, 15000);
+
         function setActiveBtn(activeBtn) {
             document.getElementById('btnHome').classList.remove("active");
             document.getElementById('btnRandomArticle').classList.remove("active");
@@ -1125,7 +1146,7 @@ define(['jquery', 'zimArchiveLoader', 'uiUtil', 'util', 'utf8', 'cache', 'images
             setContentInjectionMode(this.value);
             // If we're in a PWA UWP app, warn the user that this does not disable the PWA
             if (this.value === 'jquery' && /^http/i.test(window.location.protocol) && /UWP\|PWA/.test(params.appType) &&
-                settingsStore.getItem('allowInternetAccess') === 'true') {
+                params.allowInternetAccess === 'true') {
                 uiUtil.systemAlert(
                     '<p>Please note that switching content injection mode does not revert to local code.</p>' +
                     '<p>If you wish to exit the PWA, you will need to turn off "Allow Internet access?" above.</p>'
@@ -1188,8 +1209,11 @@ define(['jquery', 'zimArchiveLoader', 'uiUtil', 'util', 'utf8', 'cache', 'images
                         });
                     }
                 }
-                settingsStore.setItem('allowInternetAccess', false, Infinity);
+            } else {
+                // We can check for updates if the user has allowed Internet access
+                checkUpdateServer();
             }
+            settingsStore.setItem('allowInternetAccess', params.allowInternetAccess, Infinity);
         });
         $('input:checkbox[name=cssCacheMode]').on('change', function (e) {
             params.cssCache = this.checked ? true : false;

www/js/init.js

@@ -99,7 +99,7 @@ params['alphaChar'] = getSetting('alphaChar') || 'A'; //Set default start of alp
 params['omegaChar'] = getSetting('omegaChar') || 'Z'; //Set default end of alphabet string
 params['contentInjectionMode'] = getSetting('contentInjectionMode') || ((navigator.serviceWorker && !/^(ms-appx-web:)$/i.test(window.location.protocol)
     && !/Android/.test(params.appType) && !window.nw) ? 'serviceworker' : 'jquery'); // Deafault to SW mode if the browser supports it
-params['allowInternetAccess'] = getSetting('allowInternetAccess');
+params['allowInternetAccess'] = getSetting('allowInternetAccess') !== null ? getSetting('allowInternetAccess') : true;
 params['openExternalLinksInNewTabs'] = getSetting('openExternalLinksInNewTabs') !== null ? getSetting('openExternalLinksInNewTabs') : true; // Parameter to turn on/off opening external links in new tab
 params['windowOpener'] = getSetting('windowOpener'); // 'tab|window|false' A setting that determines whether right-click/long-press of a ZIM link opens a new window/tab
 params['rightClickType'] = getSetting('rightClickType'); // 'single|double|false' A setting that determines whether a single or double right-click is used to open a new window/tab

www/js/lib/uiUtil.js

@@ -674,17 +674,19 @@ define(rqDef, function(util) {
     /**
      * Shows that an upgrade is ready to install
      * @param {String} ver The version of the upgrade 
-     * @param {String} type Either 'load' or 'install' according to the type of upgrade 
+     * @param {String} type Either 'load', 'install' or 'download' according to the type of upgrade
+     * @param {String} url An optional download URL
      */
-    function showUpgradeReady(ver, type) {
+    function showUpgradeReady(ver, type, url) {
         params.upgradeNeeded = true;
         document.getElementById('alertBoxPersistent').innerHTML =
             '<div id="upgradeAlert" class="alert alert-info alert-dismissible">\n' +
             '    <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>\n' +
             '    <span id="persistentMessage"></span>\n' +
             '</div>\n';
-        document.getElementById('persistentMessage').innerHTML = 'Version ' + ver + ' is ready to '
+        document.getElementById('persistentMessage').innerHTML = 'Version ' + ver + 
-            + type + '! (Re-launch app to ' + type + '.)';
+            (url ? ' is available to ' + type + '! Go to <a href="' + url + '" style="color:white;" target="_blank">' + url + '</a>' 
+            : ' is ready to ' + type + '! (Re-launch app to ' + type + '.)');
     }
     
     /**

www/js/lib/updater.js

@@ -0,0 +1,114 @@
+/**
+ * updater.js : Functions for checking and initiating app updtes
+ * 
+ * Copyright 2013-2022 Jaifroid, Mossroy and contributors
+ * License GPL v3:
+ * 
+ * This file is part of Kiwix.
+ * 
+ * Kiwix is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * Kiwix is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with Kiwix (file LICENSE-GPLv3.txt).  If not, see <http://www.gnu.org/licenses/>
+ */
+
+'use strict';
+
+define(['uiUtil'], function (uiUtil) {
+
+    /**
+     * The update server configuration
+     */
+    params.updateServer = {
+        url: 'https://api.github.com/repos/kiwix/kiwix-js-windows/',
+        releases: 'releases'
+    };
+
+    // A RegExp prototype string to match the current app's releases
+    const baseApp = (params.packagedFile && /wikivoyage/.test(params.packagedFile)) ? 'wikivoyage' :
+        (params.packagedFile && /wikmed|mdwiki/.test(params.packagedFile)) ? 'wikimed' :
+        'windows|electron|kiwixwebapp_'; // Default value
+    
+    // A RegExp to match download URLs of releases
+    const regexpMatchGitHubReleases = RegExp('"browser_download_url[":\\s]+"(https:.*download\\/([^\\/]+).*(?:' + baseApp + ')[^"]+)"', 'ig');
+
+    /**
+     * Get and return the JSON list of releases from the update server's REST API
+     * 
+     * @param {Function} callback The function to call with the data
+     * @returns {String} A JSON string containing hierarchical release data
+     */
+    function getReleasesObject(callback) {
+        uiUtil.XHR(params.updateServer.url + params.updateServer.releases, 'text',
+            function (response, mimetype, status) {
+                if (status === 200) {
+                    callback(response);
+                } else callback('');
+            }
+        );
+    }
+
+    /**
+     * A function to get the latest updates from a GitHub releases source
+     * Only updates that are greater than the current update are returned
+     * Attempts to match by channel, but also matches non-channel releases
+     * 
+     * @param {Function} callback A function to call back with the results
+     * @returns {Object} Calls back with update tag, update URL, and array of releases
+     */
+    function getLatestUpdates(callback) {
+        var updatedReleases = [];
+        var currentRelease = params.appVersion.replace(/^v?([\d.]+)/, '$1');
+        var currentReleaseChannel = params.appVersion.replace(/^[v\d.]+/, '');
+        var updateTag;
+        var channelMatchedTag;
+        var updateUrl;
+        var channelMatchedUpdateUrl;
+        getReleasesObject(function (releases) {
+            var releaseFile;
+            var releaseVersion;
+            var releaseChannel;
+            // Loop through every line in releases
+            var matchedRelease = regexpMatchGitHubReleases.exec(releases);
+            while (matchedRelease != null) {
+                releaseFile = matchedRelease[1];
+                releaseVersion = matchedRelease[2].replace(/^v?([\d.]+).*/, '$1');
+                releaseChannel = matchedRelease[2].replace(/^[v\d.]+/, '');
+                // Compare the releases using a version-type comparison
+                if (releaseVersion.localeCompare(currentRelease, { numeric: true, sensitivity: 'base' }) === 1) {
+                    if (!channelMatchedTag && currentReleaseChannel === releaseChannel) {
+                        channelMatchedTag = matchedRelease[2];
+                        channelMatchedUpdateUrl = releaseFile.replace(/\/download\//, '/tag/').replace(/[^/]+$/, '');
+                    }
+                    if (!updateTag) updateTag = matchedRelease[2];
+                    if (!updateUrl) updateUrl = releaseFile.replace(/\/download\//, '/tag/').replace(/[^/]+$/, '');
+                    updatedReleases.push(releaseFile)
+                }
+                matchedRelease = regexpMatchGitHubReleases.exec(releases);
+            }
+            // We should now have a list of all candidate updates, and candidate channel update
+            // Compare the channel-matched update wiht the update, and if they are same underlying version number, choose channel match
+            if (updateTag && updateTag.replace(/^v?([\d.]+).*/, '$1') === channelMatchedTag.replace(/^v?([\d.]+).*/, '$1')) {
+                updateTag = channelMatchedTag;
+                updateUrl = channelMatchedUpdateUrl;
+            }
+            callback(updateTag, updateUrl, updatedReleases);
+        });
+    }
+
+
+    /**
+     * Functions and classes exposed by this module
+     */
+    return {
+        getLatestUpdates: getLatestUpdates
+    };
+});