Currently, synchronous version of pyTelegramBotAPI has two types of middlewares:
- Class-based middlewares
- Function-based middlewares
Middlewares are designed to get update before handler's execution.
This type of middleware has more functionality compared to function-based one.
Class based middleware should be instance of telebot.handler_backends.BaseMiddleware.
Each middleware should have 2 main functions:
pre_process -> is a method of class which receives update, and data.
Data - is a dictionary, which could be passed right to handler, and post_process function.
post_process -> is a function of class which receives update, data, and exception, that happened in handler. If handler was executed correctly - then exception will equal to None.
To use function-based middleware, you should set apihelper.ENABLE_MIDDLEWARE = True.
This type of middleware is created by using a decorator for middleware.
With this type middleware, you can retrieve update immediately after update came. You should set update_types as well.
- You can pass data between post, pre_process functions, and handler.
- If there is an exception in handler, you will get exception parameter with exception class in post_process.
- Has post_process -> method which works after the handler's execution.