How to get channel/chat/user name of forwarded message using Telethon?

Question

I try to get name of channel by channel id:

result = self._client(GetHistoryRequest(
        entity,
        limit=100,
        offset_date=None,
        offset_id=0,
        max_id=0,
        min_id=last_read_message_id,
        add_offset=0
    ))
for message in result.messages:
    if isinstance(message.fwd_from, MessageFwdHeader):
        fwd_channel_id = message.fwd_from.channel_id
        if fwd_channel_id:
            fwd_result = self._client(GetFullChannelRequest( # problem!!!
                InputPeerChannel(message.fwd_from.channel_id, 0)
            ))

message.fwd_from looks like:

fwd_from=MessageFwdHeader(
  channel_id=1053596007, 
  date=datetime.fromtimestamp(1507891987.0), 
  post_author=None, # None!!!
  from_id=None, 
  channel_post=3030
), 

So, I cant take channel name from message.fwd_from. And I dont join into this channel.

When I try to call GetFullChannelRequest, I have next error:

ChannelInvalidError(...), 'Invalid channel object. Make sure to pass the right types, for instance making sure that the request is designed for channels or otherwise look for a different one more suited.'

How to get name of channel properly?

Answer 1

Answer here

Example:

result = self._client(GetHistoryRequest(
        entity,
        limit=100,
        offset_date=None,
        offset_id=0,
        max_id=0,
        min_id=last_read_message_id,
        add_offset=0
    ))
for message in result.messages:
    if isinstance(message.fwd_from, MessageFwdHeader):
            entity = self._client.get_input_entity(
                PeerChannel(message.fwd_from.channel_id)
            )
            if message.fwd_from.channel_id:
                fwd_result = self._client(GetFullChannelRequest(entity))
                if hasattr(fwd_result, 'chats') and len(fwd_result.chats) > 0:
                    fwd_title = fwd_result.chats[0].title