Quiz fault-tolerant mode

This plugin is designed to allow, as far as possible, a student to continue working
on a deferred-feedback quiz attempt even if the network connection goes down.
This plugin can be turned on for particular quizzes in your Moodle site, providing they user How questions behave: Deferred feedback. The goal is to make sure that students never lose any work, even if the network or Moodle server is a bit dodgy.
With this plugin enabled, when the quiz is attempted:
All the questions are downloaded at the start, so that you can instantly switch between pages of the attempt with no further contact to the server.
When the response to a question is changed, it is saved behind the scenes (like standard quiz auto-save).
The the session gets lost, a pop-up appears where you can log in again, then you can continue with the attempt without reloading and losing your unsaved work.
At the end, when you submit, the submission is processed asynchronously, so that if an error occurs you can try again, or continue your attempt.
If auto-saving fails, then the warning shown is much less dire, since it does not matter so much.
Whenever there is unsaved data, you get a warning if you try to leave the quiz page, so you don’t accidentally lose data.
In case you never re-connect to Moodle, then a download link is provided, so you can save your responses to a file.
There is then a screen where Editing teachers or Managers can upload those locally saved responses to be processed.
The downloaded responses can be encrypted, if required.
This plugins was created by the Open University, for use in exams. We hope you find it useful.
[WARNING: if you are using a Moodle version older than 2.7.5 or 2.8.3 – not recommended – you will need to apply some patches .]