aiogram/docs/dispatcher/middlewares/basics.md

Basics

All middlewares should be made with BaseMiddleware (#!python3 from aiogram import BaseMiddleware) as base class.

For example:

class MyMiddleware(BaseMiddleware): ...

And then use next pattern in naming callback functions in middleware: on_{step}_{event}

Where is:

• #!python3 step:
  • #!python3 pre_process
  • #!python3 process
  • #!python3 post_process
• #!python3 event:
  • #!python3 update
  • #!python3 message
  • #!python3 edited_message
  • #!python3 channel_post
  • #!python3 edited_channel_post
  • #!python3 inline_query
  • #!python3 chosen_inline_result
  • #!python3 callback_query
  • #!python3 shipping_query
  • #!python3 pre_checkout_query
  • #!python3 poll
  • #!python3 poll_answer
  • #!python3 error

Connecting middleware with router

Middlewares can be connected with router by next ways:

1. #!python3 router.use(MyMiddleware()) (recommended)
2. #!python3 router.middleware.setup(MyMiddleware())
3. #!python3 MyMiddleware().setup(router.middleware) (not recommended)

!!! warning One instance of middleware can't be registered twice in single or many middleware managers

The specification of step callbacks

Pre-process step

Argument	Type	Description
event name	Any of event type (Update, Message and etc.)	Event
#!python3 data	#!python3 Dict[str, Any]	Contextual data (Will be mapped to handler arguments)

Returns #!python3 Any

Process step

Argument	Type	Description
event name	Any of event type (Update, Message and etc.)	Event
#!python3 data	#!python3 Dict[str, Any]	Contextual data (Will be mapped to handler arguments)

Returns #!python3 Any

Post-Process step

Argument	Type	Description
event name	Any of event type (Update, Message and etc.)	Event
#!python3 data	#!python3 Dict[str, Any]	Contextual data (Will be mapped to handler arguments)
#!python3 result	#!python3 Dict[str, Any]	Response from handlers

Returns #!python3 Any

Full list of available callbacks

• #!python3 on_pre_process_update - will be triggered on pre process #!python3 update event
• #!python3 on_process_update - will be triggered on process #!python3 update event
• #!python3 on_post_process_update - will be triggered on post process #!python3 update event
• #!python3 on_pre_process_message - will be triggered on pre process #!python3 message event
• #!python3 on_process_message - will be triggered on process #!python3 message event
• #!python3 on_post_process_message - will be triggered on post process #!python3 message event
• #!python3 on_pre_process_edited_message - will be triggered on pre process #!python3 edited_message event
• #!python3 on_process_edited_message - will be triggered on process #!python3 edited_message event
• #!python3 on_post_process_edited_message - will be triggered on post process #!python3 edited_message event
• #!python3 on_pre_process_channel_post - will be triggered on pre process #!python3 channel_post event
• #!python3 on_process_channel_post - will be triggered on process #!python3 channel_post event
• #!python3 on_post_process_channel_post - will be triggered on post process #!python3 channel_post event
• #!python3 on_pre_process_edited_channel_post - will be triggered on pre process #!python3 edited_channel_post event
• #!python3 on_process_edited_channel_post - will be triggered on process #!python3 edited_channel_post event
• #!python3 on_post_process_edited_channel_post - will be triggered on post process #!python3 edited_channel_post event
• #!python3 on_pre_process_inline_query - will be triggered on pre process #!python3 inline_query event
• #!python3 on_process_inline_query - will be triggered on process #!python3 inline_query event
• #!python3 on_post_process_inline_query - will be triggered on post process #!python3 inline_query event
• #!python3 on_pre_process_chosen_inline_result - will be triggered on pre process #!python3 chosen_inline_result event
• #!python3 on_process_chosen_inline_result - will be triggered on process #!python3 chosen_inline_result event
• #!python3 on_post_process_chosen_inline_result - will be triggered on post process #!python3 chosen_inline_result event
• #!python3 on_pre_process_callback_query - will be triggered on pre process #!python3 callback_query event
• #!python3 on_process_callback_query - will be triggered on process #!python3 callback_query event
• #!python3 on_post_process_callback_query - will be triggered on post process #!python3 callback_query event
• #!python3 on_pre_process_shipping_query - will be triggered on pre process #!python3 shipping_query event
• #!python3 on_process_shipping_query - will be triggered on process #!python3 shipping_query event
• #!python3 on_post_process_shipping_query - will be triggered on post process #!python3 shipping_query event
• #!python3 on_pre_process_pre_checkout_query - will be triggered on pre process #!python3 pre_checkout_query event
• #!python3 on_process_pre_checkout_query - will be triggered on process #!python3 pre_checkout_query event
• #!python3 on_post_process_pre_checkout_query - will be triggered on post process #!python3 pre_checkout_query event
• #!python3 on_pre_process_poll - will be triggered on pre process #!python3 poll event
• #!python3 on_process_poll - will be triggered on process #!python3 poll event
• #!python3 on_post_process_poll - will be triggered on post process #!python3 poll event
• #!python3 on_pre_process_poll_answer - will be triggered on pre process #!python3 poll_answer event
• #!python3 on_process_poll_answer - will be triggered on process #!python3 poll_answer event
• #!python3 on_post_process_poll_answer - will be triggered on post process #!python3 poll_answer event
• #!python3 on_pre_process_error - will be triggered on pre process #!python3 error event
• #!python3 on_process_error - will be triggered on process #!python3 error event
• #!python3 on_post_process_error - will be triggered on post process #!python3 error event