middleware

Middlewares

Type of middlewares in pyTelegramBotAPI

Currently, synchronous version of pyTelegramBotAPI has two types of middlewares:

• Class-based middlewares
• Function-based middlewares

Purpose of middlewares

Middlewares are designed to get update before handler's execution.

Class-based middlewares

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.

Function-based middlewares

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.

Why class-based middlewares are better?

• 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.

Take a look at examples for more.