Helpers for Advent of Code in C#.
To get your session secret press F12 while you are logged in on adventofcode.com to open the developer tools of your browser.
Then open the Application Tab on Chromium Browsers or Storage on firefox. There you can have a look at your cookies and copy the session id. You need to provide this session id as parameter for the InputDownloader instance.
Example:
string sessionId = "53418d7865....";
var downloader = new InputDownloader(sessionId);
var input = await downloader.GetInput(1, 2021);