explain the code/logic behind this plugin

The code is here, and it is really simple.

It uses the FORCE_SSL function, and then forces a redirect to https.

The main problem I had was that I was still able to access a website over HTTP if I manualy typed a link eg. https://example.com/subdirectory even if I changed the WP Settings to HTTPS.

The problem occured only on one website, but decided to pluginify the solution I found.

Interesting.. Before finding your plugin, I tried all the methods I found on the web. I added redirect and force https code in .htaccess. It would work for a while then out of the blue, it would crash my site until I removed the code and then reinstalled it later. You’re right though, I don’t have the same problem on other sites even though they’re all running a similar setup. Some things you simply can’t explain. Anyhow, it’s been months without any further issues so thank you again for creating the plugin!