Issue 6786 - Display the Safari App Extension migration page

background.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 44 matching lines @@
     targetPage = sender.page;
 
   if (targetPage)
   {
     msg.payload.sender = sender.page.id;
     if (msg.expectsResponse)
       return new Promise(targetPage.sendMessage.bind(targetPage, msg.payload));
     targetPage.sendMessage(msg.payload);
   }
 });
+
+// Display a page to explain to users of Safari 10 and higher that they need
+// to migrate to our Safari App extension, but only once the migration page
+// is online.
+
+function showMigrationPageWhenReady()
+{
+  fetch("https://eyeo.to/adblockplus/safari-app-extension-migration")

[Sebastian Noack, 2018/07/13 18:01:35]

I wonder, should we perhaps just send a HEAD request instead of downloading the
whole document?

[kzar, 2018/07/13 18:44:04]

Done.

+    .then(function(response)
+    {
+      if (response.ok)
+        ext.showPage(response.url);
+    });
+}
+
+if (Services.vc.compare(require("info").applicationVersion, "10") >= 0)
+{
+  // Show now, and then once every 24 hours.
+  showMigrationPageWhenReady();
+  window.setInterval(showMigrationPageWhenReady, 1000 * 60 * 60 * 24);

[Sebastian Noack, 2018/07/13 18:01:35]

As far as I understand the issue description, we only want to try again in 24h
if the page wasn't online yet. Also then we don't have to bother about the
scenario in which the tab is already open, just using ext.pages.open() here, and
don't need to touch (and re-test) the logic showing the options page.

Furthermore, we might want to call setTimeout() (recursively) instead of using
setInterval(). That is because if an interval is missed while your computer was
in standby/sleep it is skipped, however if a timeout was missed, it is performed
as soon as you resume from standby.

[kzar, 2018/07/13 18:44:04]

I've adjusted the issue description to clarify.
Good point, done.

+}