Handling Updates

Invoking API methods sequentially is one way to use Hydrogram. This page deals with Telegram updates and how to handle new incoming messages or other events in Hydrogram.

Defining Updates

Updates are events that happen in your Telegram account (incoming messages, new members join, bot button presses, etc.), which are meant to notify you about a new specific state that has changed. These updates are handled by registering one or more callback functions in your app using Handlers.

Each handler deals with a specific event and once a matching update arrives from Telegram, your registered callback function will be called back by the framework and its body executed.

Registering a Handler

To explain how handlers work let’s examine the one which will be in charge for handling Message updates coming from all around your chats. Every other kind of handler shares the same setup logic and you should not have troubles settings them up once you learn from this section.

Using Decorators

The most elegant way to register a message handler is by using the on_message() decorator:

from hydrogram import Client

app = Client("my_account")

async def my_handler(client, message):
    await message.forward("me")


The defined function my_handler, which accepts the two arguments (client, message), will be the function that gets executed every time a new message arrives.

In the last line we see again the run() method, this time used without any argument. Its purpose here is simply to automatically start(), keep the Client online so that it can listen for updates and stop() it once you hit CTRL+C.

Using add_handler()

The add_handler() method takes any handler instance that wraps around your defined callback function and registers it in your Client. It is useful in case you want to programmatically add handlers.

from hydrogram import Client
from hydrogram.handlers import MessageHandler

async def my_function(client, message):
    await message.forward("me")

app = Client("my_account")

my_handler = MessageHandler(my_function)