Better handling of sessions about pyrogram

[delivrance]

What raises the FLOOD_WAIT_X error is ExportAuthorization.
The problem is that Pyrogram creates new keys for every file downloaded, and the server is limiting us in doing so. We should instead create one, cache it and re-use it when needed.

[delivrance]

@surkum Can I ask you how many files have you tried to download? More or less. Just to get an idea of when such situation would occur.

[surkum]

@delivrance I was trying to backup a long conversation (14K messages), and all it's media files(~2000), it started to fail around 400

[delivrance]

@surkum Hi. I've pushed some changes to a new branch. Use pip3 install -U git+https://github.com/pyrogram/pyrogram@cache-sessions to test this out and tell me how it goes.

[surkum]

@delivrance I can confirm that the issue is solved with this patch, I've been able to download +3K media elements from a stream without problems. thx.

[delivrance]

Let's keep this open as a reminder until is merged.

[iamnalinor]

I had this issue again recently. After research, I found that the part with media_sessions caching was removed in following commit: 8441ce2f

@delivrance Can you tell why you removed this code? Is there any issues coming from Telegram servers or you just forgot to add this functionality while refactoring get_file() code? I found no comments about it.

[enterFaisal]

I also got the same error

File "/opt/python/pyrogram/client.py", line 870, in get_file
    exported_auth = await self.invoke(
  File "/opt/python/pyrogram/methods/advanced/invoke.py", line 79, in invoke
    r = await self.session.invoke(
  File "/opt/python/pyrogram/session/session.py", line 389, in invoke
    return await self.send(query, timeout=timeout)
  File "/opt/python/pyrogram/session/session.py", line 357, in send
    RPCError.raise_it(result, type(data))
  File "/opt/python/pyrogram/errors/rpc_error.py", line 91, in raise_it
    raise getattr(
pyrogram.errors.exceptions.flood_420.FloodWait: Telegram says: [420 FLOOD_WAIT_X] - A wait of 833 seconds is required (caused by "auth.ExportAuthorization")