Telethon/readthedocs/extra/advanced-usage/working-with-messages.rst

=========================
Working with messages
=========================

.. note::
    Make sure you have gone through :ref:`prelude` already!


Forwarding messages
*******************

Note that ForwardMessageRequest_ (note it's Message, singular) will *not* work if channels are involved.
This is because channel (and megagroups) IDs are not unique, so you also need to know who the sender is
(a parameter this request doesn't have).

Either way, you are encouraged to use ForwardMessagesRequest_ (note it's Message*s*, plural) *always*,
since it is more powerful, as follows:

    .. code-block:: python

        from telethon.tl.functions.messages import ForwardMessagesRequest
        #                                             note the s ^

        messages = foo()  # retrieve a few messages (or even one, in a list)
        from_entity = bar()
        to_entity = baz()

        client(ForwardMessagesRequest(
            from_peer=from_entity,  # who sent these messages?
            id=[msg.id for msg in messages],  # which are the messages?
            to_peer=to_entity  # who are we forwarding them to?
        ))

The named arguments are there for clarity, although they're not needed because they appear in order.
You can obviously just wrap a single message on the list too, if that's all you have.


Searching Messages
*******************

Messages are searched through the obvious SearchRequest_, but you may run into issues_. A valid example would be:

    .. code-block:: python

        result = client(SearchRequest(
            entity, 'query', InputMessagesFilterEmpty(), None, None, 0, 0, 100
        ))

It's important to note that the optional parameter ``from_id`` has been left omitted and thus defaults to ``None``.
Changing it to InputUserEmpty_, as one could think to specify "no user", won't work because this parameter is a flag,
and it being unspecified has a different meaning.

If one were to set ``from_id=InputUserEmpty()``, it would filter messages from "empty" senders,
which would likely match no users.

If you get a ``ChatAdminRequiredError`` on a channel, it's probably because you tried setting the ``from_id`` filter,
and as the error says, you can't do that. Leave it set to ``None`` and it should work.

As with every method, make sure you use the right ID/hash combination for your ``InputUser`` or ``InputChat``,
or you'll likely run into errors like ``UserIdInvalidError``.


Sending stickers
*****************

Stickers are nothing else than ``files``, and when you successfully retrieve the stickers for a certain sticker set,
all you will have are ``handles`` to these files. Remember, the files Telegram holds on their servers can be referenced
through this pair of ID/hash (unique per user), and you need to use this handle when sending a "document" message.
This working example will send yourself the very first sticker you have:

    .. code-block:: python

        # Get all the sticker sets this user has
        sticker_sets = client(GetAllStickersRequest(0))

        # Choose a sticker set
        sticker_set = sticker_sets.sets[0]

        # Get the stickers for this sticker set
        stickers = client(GetStickerSetRequest(
            stickerset=InputStickerSetID(
                id=sticker_set.id, access_hash=sticker_set.access_hash
            )
        ))

        # Stickers are nothing more than files, so send that
        client(SendMediaRequest(
            peer=client.get_me(),
            media=InputMediaDocument(
                id=InputDocument(
                    id=stickers.documents[0].id,
                    access_hash=stickers.documents[0].access_hash
                ),
                caption=''
            )
        ))


.. _ForwardMessageRequest: https://lonamiwebs.github.io/Telethon/methods/messages/forward_message.html
.. _ForwardMessagesRequest: https://lonamiwebs.github.io/Telethon/methods/messages/forward_messages.html
.. _SearchRequest: https://lonamiwebs.github.io/Telethon/methods/messages/search.html
.. _issues: https://github.com/LonamiWebs/Telethon/issues/215
.. _InputUserEmpty: https://lonamiwebs.github.io/Telethon/constructors/input_user_empty.html