Update Handling
===============

Updates are events that happen in your Telegram account (incoming messages, new channel posts, new members join, ...)
and are handled by registering one or more callback functions with an Handler. There are multiple Handlers to choose
from, one for each kind of update.

Registering an Handler
----------------------

We shall examine the :obj:`MessageHandler <pyrogram.MessageHandler>`, which will be in charge for handling
:obj:`Message <pyrogram.api.types.pyrogram.Message>` objects.

The easiest and nicest way to register a MessageHandler is by decorating your function with the
:meth:`on_message() <pyrogram.Client.on_message>` decorator. Here's a full example that prints out the content
of a message as soon as it arrives.

.. code-block:: python

    from pyrogram import Client

    app = Client("my_account")


    @app.on_message()
    def my_handler(client, message):
        print(message)


    app.start()
    app.idle()

If you prefer not to use decorators, there is an alternative way for registering Handlers.
This is useful, for example, if you want to keep your callback functions in a separate file.

.. code-block:: python

    from pyrogram import Client, MessageHandler


    def my_handler(client, message):
        print(message)


    app = Client("my_account")

    app.add_handler(MessageHandler(my_handler))

    app.start()
    app.idle()


Using Filters
-------------

For a finer grained control over what kind of messages will be allowed or not in your callback functions, you can use
:class:`Filters <pyrogram.Filters>`. The next example will show you how to handler only messages
containing an :obj:`Audio <pyrogram.api.types.pyrogram.Audio>` object:

.. code-block:: python

    from pyrogram import Filters


    @app.on_message(Filters.audio)
    def my_handler(client, message):
        print(message)

or, without decorators:

.. code-block:: python

    from pyrogram import Filters, Messagehandler


    def my_handler(client, message):
        print(message)


    app.add_handler(MessageHandler(my_handler, Filters.audio))

Combining Filters
-----------------

Filters can also be used in a more advanced way by combining more filters together using bitwise operators:

-   Use ``~`` to invert a filter (behaves like the ``not`` operator).
-   Use ``&`` and ``|`` to merge two filters (behave like ``and``, ``or`` operators respectively).

Here are some examples:

-   Message is a **text** message **and** is **not edited**.

    .. code-block:: python

        @app.on_message(Filters.text & ~Filters.edited)
        def my_handler(client, message):
            print(message)

-   Message is a **sticker** **and** is coming from a **channel** or a **private** chat.

    .. code-block:: python

        @app.on_message(Filters.sticker & (Filters.channel | Filters.private))
        def my_handler(client, message):
            print(message)

Advanced Filters
----------------

Some filters, like :obj:`command() <pyrogram.Filters.command>` or :obj:`regex() <pyrogram.Filters.regex>`
can also accept arguments:

-   Message is either a */start* or */help* **command**.

    .. code-block:: python

        @app.on_message(Filters.command(["start", "help"]))
        def my_handler(client, message):
            print(message)

-   Message is a **text** message matching the given regex pattern.

    .. code-block:: python

        @app.on_message(Filters.regex("pyrogram"))
        def my_handler(client, message):
            print(message)

More handlers using different filters can be created as well:

.. code-block:: python

    @app.on_message(Filters.command("start"))
    def start_command(client, message):
        print("This is the /start command")


    @app.on_message(Filters.command("help"))
    def help_command(client, message):
        print("This is the /help command")


    @app.on_message(Filters.chat("PyrogramChat"))
    def my_handler(client, message):
        print("New message in @PyrogramChat")