How do I use middleware with best practices.

[oceanm7n]

I want to use a middleware to incorporate custom service logic into my bot, that requires it to stop processing a command if certain conditions are met.

How do I explicitly stop every message_handler decorator from processing a command if various conditions are met inside the middleware?

[coder2020official]

You need to return either telebot.handler_backends.CancelUpdate or telebot.handler_backends.SkipHandler

Returning SkipHandler will skip the handler execution and will call your post_process middleware function.
Returning CancelUpdate will cancel execution of both post_process function, and your handler.

Here's the example of using CancelUpdate:

Link