client.py

#  Pyrogram - Telegram MTProto API Client Library for Python
#  Copyright (C) 2017-present Dan <https://github.com/delivrance>
#
#  This file is part of Pyrogram.
#
#  Pyrogram is free software: you can redistribute it and/or modify
#  it under the terms of the GNU Lesser General Public License as published
#  by the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  Pyrogram is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU Lesser General Public License for more details.
#
#  You should have received a copy of the GNU Lesser General Public License
#  along with Pyrogram.  If not, see <http://www.gnu.org/licenses/>.

import asyncio
import functools
import inspect
import logging
import os
import platform
import re
import shutil
import sys
from concurrent.futures.thread import ThreadPoolExecutor
from hashlib import sha256
from importlib import import_module
from io import StringIO, BytesIO
from mimetypes import MimeTypes
from pathlib import Path
from typing import Union, List, Optional, Callable, AsyncGenerator

import pyrogram
from pyrogram import __version__, __license__
from pyrogram import enums
from pyrogram import raw
from pyrogram import utils
from pyrogram.crypto import aes
from pyrogram.errors import CDNFileHashMismatch
from pyrogram.errors import (
    SessionPasswordNeeded,
    VolumeLocNotFound, ChannelPrivate,
    AuthBytesInvalid, BadRequest
)
from pyrogram.handlers.handler import Handler
from pyrogram.methods import Methods
from pyrogram.session import Auth, Session
from pyrogram.storage import FileStorage, MemoryStorage
from pyrogram.types import User, TermsOfService
from pyrogram.utils import ainput
from .dispatcher import Dispatcher
from .file_id import FileId, FileType, ThumbnailSource
from .mime_types import mime_types
from .parser import Parser
from .session.internals import MsgId

log = logging.getLogger(__name__)


class Client(Methods):
    """Pyrogram Client, the main means for interacting with Telegram.

    Parameters:
        name (``str``):
            A name for the client, e.g.: "my_account".

        api_id (``int`` | ``str``, *optional*):
            The *api_id* part of the Telegram API key, as integer or string.
            E.g.: 12345 or "12345".

        api_hash (``str``, *optional*):
            The *api_hash* part of the Telegram API key, as string.
            E.g.: "0123456789abcdef0123456789abcdef".

        app_version (``str``, *optional*):
            Application version.
            Defaults to "Pyrogram x.y.z".

        device_model (``str``, *optional*):
            Device model.
            Defaults to *platform.python_implementation() + " " + platform.python_version()*.

        system_version (``str``, *optional*):
            Operating System version.
            Defaults to *platform.system() + " " + platform.release()*.

        lang_code (``str``, *optional*):
            Code of the language used on the client, in ISO 639-1 standard.
            Defaults to "en".

        ipv6 (``bool``, *optional*):
            Pass True to connect to Telegram using IPv6.
            Defaults to False (IPv4).

        proxy (``dict``, *optional*):
            The Proxy settings as dict.
            E.g.: *dict(scheme="socks5", hostname="11.22.33.44", port=1234, username="user", password="pass")*.
            The *username* and *password* can be omitted if the proxy doesn't require authorization.

        test_mode (``bool``, *optional*):
            Enable or disable login to the test servers.
            Only applicable for new sessions and will be ignored in case previously created sessions are loaded.
            Defaults to False.

        bot_token (``str``, *optional*):
            Pass the Bot API token to create a bot session, e.g.: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11"
            Only applicable for new sessions.

        session_string (``str``, *optional*):
            Pass a session string to load the session in-memory.
            Implies ``in_memory=True``.

        in_memory (``bool``, *optional*):
            Pass True to start an in-memory session that will be discarded as soon as the client stops.
            In order to reconnect again using an in-memory session without having to login again, you can use
            :meth:`~pyrogram.Client.export_session_string` before stopping the client to get a session string you can
            pass to the ``session_string`` parameter.
            Defaults to False.

        phone_number (``str``, *optional*):
            Pass the phone number as string (with the Country Code prefix included) to avoid entering it manually.
            Only applicable for new sessions.

        phone_code (``str``, *optional*):
            Pass the phone code as string (for test numbers only) to avoid entering it manually.
            Only applicable for new sessions.

        password (``str``, *optional*):
            Pass the Two-Step Verification password as string (if required) to avoid entering it manually.
            Only applicable for new sessions.

        workers (``int``, *optional*):
            Number of maximum concurrent workers for handling incoming updates.
            Defaults to ``min(32, os.cpu_count() + 4)``.

        workdir (``str``, *optional*):
            Define a custom working directory.
            The working directory is the location in the filesystem where Pyrogram will store the session files.
            Defaults to the parent directory of the main script.

        plugins (``dict``, *optional*):
            Smart Plugins settings as dict, e.g.: *dict(root="plugins")*.

        parse_mode (:obj:`~pyrogram.enums.ParseMode`, *optional*):
            Set the global parse mode of the client. By default, texts are parsed using both Markdown and HTML styles.
            You can combine both syntaxes together.

        no_updates (``bool``, *optional*):
            Pass True to disable incoming updates.
            When updates are disabled the client can't receive messages or other updates.
            Useful for batch programs that don't need to deal with updates.
            Defaults to False (updates enabled and received).

        takeout (``bool``, *optional*):
            Pass True to let the client use a takeout session instead of a normal one, implies *no_updates=True*.
            Useful for exporting Telegram data. Methods invoked inside a takeout session (such as get_chat_history,
            download_media, ...) are less prone to throw FloodWait exceptions.
            Only available for users, bots will ignore this parameter.
            Defaults to False (normal session).

        sleep_threshold (``int``, *optional*):
            Set a sleep threshold for flood wait exceptions happening globally in this client instance, below which any
            request that raises a flood wait will be automatically invoked again after sleeping for the required amount
            of time. Flood wait exceptions requiring higher waiting times will be raised.
            Defaults to 10 seconds.

        hide_password (``bool``, *optional*):
            Pass True to hide the password when typing it during the login.
            Defaults to False, because ``getpass`` (the library used) is known to be problematic in some
            terminal environments.
    """

    APP_VERSION = f"Pyrogram {__version__}"
    DEVICE_MODEL = f"{platform.python_implementation()} {platform.python_version()}"
    SYSTEM_VERSION = f"{platform.system()} {platform.release()}"

    LANG_CODE = "en"

    PARENT_DIR = Path(sys.argv[0]).parent

    INVITE_LINK_RE = re.compile(r"^(?:https?://)?(?:www\.)?(?:t(?:elegram)?\.(?:org|me|dog)/(?:joinchat/|\+))([\w-]+)$")
    WORKERS = min(32, (os.cpu_count() or 0) + 4)  # os.cpu_count() can be None
    WORKDIR = PARENT_DIR

    mimetypes = MimeTypes()
    mimetypes.readfp(StringIO(mime_types))

    def __init__(
        self,
        name: str,
        api_id: Union[int, str] = None,
        api_hash: str = None,
        app_version: str = APP_VERSION,
        device_model: str = DEVICE_MODEL,
        system_version: str = SYSTEM_VERSION,
        lang_code: str = LANG_CODE,
        ipv6: bool = False,
        proxy: dict = None,
        test_mode: bool = False,
        bot_token: str = None,
        session_string: str = None,
        in_memory: bool = None,
        phone_number: str = None,
        phone_code: str = None,
        password: str = None,
        workers: int = WORKERS,
        workdir: str = WORKDIR,
        plugins: dict = None,
        parse_mode: "enums.ParseMode" = enums.ParseMode.DEFAULT,
        no_updates: bool = None,
        takeout: bool = None,
        sleep_threshold: int = Session.SLEEP_THRESHOLD,
        hide_password: bool = False
    ):
        super().__init__()

        self.name = name
        self.api_id = int(api_id) if api_id else None
        self.api_hash = api_hash
        self.app_version = app_version
        self.device_model = device_model
        self.system_version = system_version
        self.lang_code = lang_code
        self.ipv6 = ipv6
        self.proxy = proxy
        self.test_mode = test_mode
        self.bot_token = bot_token
        self.session_string = session_string
        self.in_memory = in_memory
        self.phone_number = phone_number
        self.phone_code = phone_code
        self.password = password
        self.workers = workers
        self.workdir = Path(workdir)
        self.plugins = plugins
        self.parse_mode = parse_mode
        self.no_updates = no_updates
        self.takeout = takeout
        self.sleep_threshold = sleep_threshold
        self.hide_password = hide_password

        self.executor = ThreadPoolExecutor(self.workers, thread_name_prefix="Handler")

        if self.session_string:
            self.storage = MemoryStorage(self.name, self.session_string)
        elif self.in_memory:
            self.storage = MemoryStorage(self.name)
        else:
            self.storage = FileStorage(self.name, self.workdir)

        self.dispatcher = Dispatcher(self)

        self.rnd_id = MsgId

        self.parser = Parser(self)

        self.session = None

        self.media_sessions = {}
        self.media_sessions_lock = asyncio.Lock()

        self.is_connected = None
        self.is_initialized = None

        self.takeout_id = None

        self.disconnect_handler = None

        self.me: Optional[User] = None

        self.message_cache = Cache(10000)

        self.loop = asyncio.get_event_loop()

    def __enter__(self):
        return self.start()

    def __exit__(self, *args):
        try:
            self.stop()
        except ConnectionError:
            pass

    async def __aenter__(self):
        return await self.start()

    async def __aexit__(self, *args):
        try:
            await self.stop()
        except ConnectionError:
            pass

    async def authorize(self) -> User:
        if self.bot_token:
            return await self.sign_in_bot(self.bot_token)

        print(f"Welcome to Pyrogram (version {__version__})")
        print(f"Pyrogram is free software and comes with ABSOLUTELY NO WARRANTY. Licensed\n"
              f"under the terms of the {__license__}.\n")

        while True:
            try:
                if not self.phone_number:
                    while True:
                        value = await ainput("Enter phone number or bot token: ")

                        if not value:
                            continue

                        confirm = (await ainput(f'Is "{value}" correct? (y/N): ')).lower()

                        if confirm == "y":
                            break

                    if ":" in value:
                        self.bot_token = value
                        return await self.sign_in_bot(value)
                    else:
                        self.phone_number = value

                sent_code = await self.send_code(self.phone_number)
            except BadRequest as e:
                print(e.MESSAGE)
                self.phone_number = None
                self.bot_token = None
            else:
                break

        sent_code_descriptions = {
            enums.SentCodeType.APP: "Telegram app",
            enums.SentCodeType.SMS: "SMS",
            enums.SentCodeType.CALL: "phone call",
            enums.SentCodeType.FLASH_CALL: "phone flash call"
        }

        print(f"The confirmation code has been sent via {sent_code_descriptions[sent_code.type]}")

        while True:
            if not self.phone_code:
                self.phone_code = await ainput("Enter confirmation code: ")

            try:
                signed_in = await self.sign_in(self.phone_number, sent_code.phone_code_hash, self.phone_code)
            except BadRequest as e:
                print(e.MESSAGE)
                self.phone_code = None
            except SessionPasswordNeeded as e:
                print(e.MESSAGE)

                while True:
                    print("Password hint: {}".format(await self.get_password_hint()))

                    if not self.password:
                        self.password = await ainput("Enter password (empty to recover): ", hide=self.hide_password)

                    try:
                        if not self.password:
                            confirm = await ainput("Confirm password recovery (y/n): ")

                            if confirm == "y":
                                email_pattern = await self.send_recovery_code()
                                print(f"The recovery code has been sent to {email_pattern}")

                                while True:
                                    recovery_code = await ainput("Enter recovery code: ")

                                    try:
                                        return await self.recover_password(recovery_code)
                                    except BadRequest as e:
                                        print(e.MESSAGE)
                                    except Exception as e:
                                        log.error(e, exc_info=True)
                                        raise
                            else:
                                self.password = None
                        else:
                            return await self.check_password(self.password)
                    except BadRequest as e:
                        print(e.MESSAGE)
                        self.password = None
            else:
                break

        if isinstance(signed_in, User):
            return signed_in

        while True:
            first_name = await ainput("Enter first name: ")
            last_name = await ainput("Enter last name (empty to skip): ")

            try:
                signed_up = await self.sign_up(
                    self.phone_number,
                    sent_code.phone_code_hash,
                    first_name,
                    last_name
                )
            except BadRequest as e:
                print(e.MESSAGE)
            else:
                break

        if isinstance(signed_in, TermsOfService):
            print("\n" + signed_in.text + "\n")
            await self.accept_terms_of_service(signed_in.id)

        return signed_up

    def set_parse_mode(self, parse_mode: Optional["enums.ParseMode"]):
        """Set the parse mode to be used globally by the client.

        When setting the parse mode with this method, all other methods having a *parse_mode* parameter will follow the
        global value by default.

        Parameters:
            parse_mode (:obj:`~pyrogram.enums.ParseMode`):
                By default, texts are parsed using both Markdown and HTML styles.
                You can combine both syntaxes together.

        Example:
            .. code-block:: python

                from pyrogram import enums

                # Default combined mode: Markdown + HTML
                await app.send_message("me", "1. **markdown** and <i>html</i>")

                # Force Markdown-only, HTML is disabled
                app.set_parse_mode(enums.ParseMode.MARKDOWN)
                await app.send_message("me", "2. **markdown** and <i>html</i>")

                # Force HTML-only, Markdown is disabled
                app.set_parse_mode(enums.ParseMode.HTML)
                await app.send_message("me", "3. **markdown** and <i>html</i>")

                # Disable the parser completely
                app.set_parse_mode(enums.ParseMode.DISABLED)
                await app.send_message("me", "4. **markdown** and <i>html</i>")

                # Bring back the default combined mode
                app.set_parse_mode(enums.ParseMode.DEFAULT)
                await app.send_message("me", "5. **markdown** and <i>html</i>")
        """

        self.parse_mode = parse_mode

    async def fetch_peers(self, peers: List[Union[raw.types.User, raw.types.Chat, raw.types.Channel]]) -> bool:
        is_min = False
        parsed_peers = []

        for peer in peers:
            if getattr(peer, "min", False):
                is_min = True
                continue

            username = None
            phone_number = None

            if isinstance(peer, raw.types.User):
                peer_id = peer.id
                access_hash = peer.access_hash
                username = (peer.username or "").lower() or None
                phone_number = peer.phone
                peer_type = "bot" if peer.bot else "user"
            elif isinstance(peer, (raw.types.Chat, raw.types.ChatForbidden)):
                peer_id = -peer.id
                access_hash = 0
                peer_type = "group"
            elif isinstance(peer, (raw.types.Channel, raw.types.ChannelForbidden)):
                peer_id = utils.get_channel_id(peer.id)
                access_hash = peer.access_hash
                username = (getattr(peer, "username", None) or "").lower() or None
                peer_type = "channel" if peer.broadcast else "supergroup"
            else:
                continue

            parsed_peers.append((peer_id, access_hash, peer_type, username, phone_number))

        await self.storage.update_peers(parsed_peers)

        return is_min

    async def handle_updates(self, updates):
        if isinstance(updates, (raw.types.Updates, raw.types.UpdatesCombined)):
            is_min = any((
                await self.fetch_peers(updates.users),
                await self.fetch_peers(updates.chats),
            ))

            users = {u.id: u for u in updates.users}
            chats = {c.id: c for c in updates.chats}

            for update in updates.updates:
                channel_id = getattr(
                    getattr(
                        getattr(
                            update, "message", None
                        ), "peer_id", None
                    ), "channel_id", None
                ) or getattr(update, "channel_id", None)

                pts = getattr(update, "pts", None)
                pts_count = getattr(update, "pts_count", None)

                if isinstance(update, raw.types.UpdateChannelTooLong):
                    log.warning(update)

                if isinstance(update, raw.types.UpdateNewChannelMessage) and is_min:
                    message = update.message

                    if not isinstance(message, raw.types.MessageEmpty):
                        try:
                            diff = await self.invoke(
                                raw.functions.updates.GetChannelDifference(
                                    channel=await self.resolve_peer(utils.get_channel_id(channel_id)),
                                    filter=raw.types.ChannelMessagesFilter(
                                        ranges=[raw.types.MessageRange(
                                            min_id=update.message.id,
                                            max_id=update.message.id
                                        )]
                                    ),
                                    pts=pts - pts_count,
                                    limit=pts
                                )
                            )
                        except ChannelPrivate:
                            pass
                        else:
                            if not isinstance(diff, raw.types.updates.ChannelDifferenceEmpty):
                                users.update({u.id: u for u in diff.users})
                                chats.update({c.id: c for c in diff.chats})

                self.dispatcher.updates_queue.put_nowait((update, users, chats))
        elif isinstance(updates, (raw.types.UpdateShortMessage, raw.types.UpdateShortChatMessage)):
            diff = await self.invoke(
                raw.functions.updates.GetDifference(
                    pts=updates.pts - updates.pts_count,
                    date=updates.date,
                    qts=-1
                )
            )

            if diff.new_messages:
                self.dispatcher.updates_queue.put_nowait((
                    raw.types.UpdateNewMessage(
                        message=diff.new_messages[0],
                        pts=updates.pts,
                        pts_count=updates.pts_count
                    ),
                    {u.id: u for u in diff.users},
                    {c.id: c for c in diff.chats}
                ))
            else:
                if diff.other_updates:  # The other_updates list can be empty
                    self.dispatcher.updates_queue.put_nowait((diff.other_updates[0], {}, {}))
        elif isinstance(updates, raw.types.UpdateShort):
            self.dispatcher.updates_queue.put_nowait((updates.update, {}, {}))
        elif isinstance(updates, raw.types.UpdatesTooLong):
            log.info(updates)

    async def load_session(self):
        await self.storage.open()

        session_empty = any([
            await self.storage.test_mode() is None,
            await self.storage.auth_key() is None,
            await self.storage.user_id() is None,
            await self.storage.is_bot() is None
        ])

        if session_empty:
            if not self.api_id or not self.api_hash:
                raise AttributeError("The API key is required for new authorizations. "
                                     "More info: https://docs.pyrogram.org/start/auth")

            await self.storage.api_id(self.api_id)

            await self.storage.dc_id(2)
            await self.storage.date(0)

            await self.storage.test_mode(self.test_mode)
            await self.storage.auth_key(
                await Auth(
                    self, await self.storage.dc_id(),
                    await self.storage.test_mode()
                ).create()
            )
            await self.storage.user_id(None)
            await self.storage.is_bot(None)
        else:
            # Needed for migration from storage v2 to v3
            if not await self.storage.api_id():
                if self.api_id:
                    await self.storage.api_id(self.api_id)
                else:
                    while True:
                        try:
                            value = int(await ainput("Enter the api_id part of the API key: "))

                            if value <= 0:
                                print("Invalid value")
                                continue

                            confirm = (await ainput(f'Is "{value}" correct? (y/N): ')).lower()

                            if confirm == "y":
                                await self.storage.api_id(value)
                                break
                        except Exception as e:
                            print(e)

    def load_plugins(self):
        if self.plugins:
            plugins = self.plugins.copy()

            for option in ["include", "exclude"]:
                if plugins.get(option, []):
                    plugins[option] = [
                        (i.split()[0], i.split()[1:] or None)
                        for i in self.plugins[option]
                    ]
        else:
            return

        if plugins.get("enabled", True):
            root = plugins["root"]
            include = plugins.get("include", [])
            exclude = plugins.get("exclude", [])

            count = 0

            if not include:
                for path in sorted(Path(root.replace(".", "/")).rglob("*.py")):
                    module_path = '.'.join(path.parent.parts + (path.stem,))
                    module = import_module(module_path)

                    for name in vars(module).keys():
                        # noinspection PyBroadException
                        try:
                            for handler, group in getattr(module, name).handlers:
                                if isinstance(handler, Handler) and isinstance(group, int):
                                    self.add_handler(handler, group)

                                    log.info('[{}] [LOAD] {}("{}") in group {} from "{}"'.format(
                                        self.name, type(handler).__name__, name, group, module_path))

                                    count += 1
                        except Exception:
                            pass
            else:
                for path, handlers in include:
                    module_path = root + "." + path
                    warn_non_existent_functions = True

                    try:
                        module = import_module(module_path)
                    except ImportError:
                        log.warning(f'[{self.name}] [LOAD] Ignoring non-existent module "{module_path}"')
                        continue

                    if "__path__" in dir(module):
                        log.warning(f'[{self.name}] [LOAD] Ignoring namespace "{module_path}"')
                        continue

                    if handlers is None:
                        handlers = vars(module).keys()
                        warn_non_existent_functions = False

                    for name in handlers:
                        # noinspection PyBroadException
                        try:
                            for handler, group in getattr(module, name).handlers:
                                if isinstance(handler, Handler) and isinstance(group, int):
                                    self.add_handler(handler, group)

                                    log.info('[{}] [LOAD] {}("{}") in group {} from "{}"'.format(
                                        self.name, type(handler).__name__, name, group, module_path))

                                    count += 1
                        except Exception:
                            if warn_non_existent_functions:
                                log.warning('[{}] [LOAD] Ignoring non-existent function "{}" from "{}"'.format(
                                    self.name, name, module_path))

            if exclude:
                for path, handlers in exclude:
                    module_path = root + "." + path
                    warn_non_existent_functions = True

                    try:
                        module = import_module(module_path)
                    except ImportError:
                        log.warning(f'[{self.name}] [UNLOAD] Ignoring non-existent module "{module_path}"')
                        continue

                    if "__path__" in dir(module):
                        log.warning(f'[{self.name}] [UNLOAD] Ignoring namespace "{module_path}"')
                        continue

                    if handlers is None:
                        handlers = vars(module).keys()
                        warn_non_existent_functions = False

                    for name in handlers:
                        # noinspection PyBroadException
                        try:
                            for handler, group in getattr(module, name).handlers:
                                if isinstance(handler, Handler) and isinstance(group, int):
                                    self.remove_handler(handler, group)

                                    log.info('[{}] [UNLOAD] {}("{}") from group {} in "{}"'.format(
                                        self.name, type(handler).__name__, name, group, module_path))

                                    count -= 1
                        except Exception:
                            if warn_non_existent_functions:
                                log.warning('[{}] [UNLOAD] Ignoring non-existent function "{}" from "{}"'.format(
                                    self.name, name, module_path))

            if count > 0:
                log.info('[{}] Successfully loaded {} plugin{} from "{}"'.format(
                    self.name, count, "s" if count > 1 else "", root))
            else:
                log.warning(f'[{self.name}] No plugin loaded from "{root}"')

    async def handle_download(self, packet):
        file_id, directory, file_name, in_memory, file_size, progress, progress_args = packet

        os.makedirs(directory, exist_ok=True) if not in_memory else None
        temp_file_path = os.path.abspath(re.sub("\\\\", "/", os.path.join(directory, file_name))) + ".temp"
        file = BytesIO() if in_memory else open(temp_file_path, "wb")

        try:
            async for chunk in self.get_file(file_id, file_size, 0, 0, progress, progress_args):
                file.write(chunk)
        except BaseException as e:
            if not in_memory:
                file.close()
                os.remove(temp_file_path)

            if isinstance(e, asyncio.CancelledError):
                raise e

            return None
        else:
            if in_memory:
                file.name = file_name
                return file
            else:
                file.close()
                file_path = os.path.splitext(temp_file_path)[0]
                shutil.move(temp_file_path, file_path)
                return file_path

    async def get_file(
        self,
        file_id: FileId,
        file_size: int = 0,
        limit: int = 0,
        offset: int = 0,
        progress: Callable = None,
        progress_args: tuple = ()
    ) -> Optional[AsyncGenerator[bytes, None]]:
        dc_id = file_id.dc_id

        async with self.media_sessions_lock:
            session = self.media_sessions.get(dc_id, None)

            if session is None:
                if dc_id != await self.storage.dc_id():
                    session = Session(
                        self, dc_id, await Auth(self, dc_id, await self.storage.test_mode()).create(),
                        await self.storage.test_mode(), is_media=True
                    )
                    await session.start()

                    for _ in range(3):
                        exported_auth = await self.invoke(
                            raw.functions.auth.ExportAuthorization(
                                dc_id=dc_id
                            )
                        )

                        try:
                            await session.invoke(
                                raw.functions.auth.ImportAuthorization(
                                    id=exported_auth.id,
                                    bytes=exported_auth.bytes
                                )
                            )
                        except AuthBytesInvalid:
                            continue
                        else:
                            break
                    else:
                        await session.stop()
                        raise AuthBytesInvalid
                else:
                    session = Session(
                        self, dc_id, await self.storage.auth_key(),
                        await self.storage.test_mode(), is_media=True
                    )
                    await session.start()

                self.media_sessions[dc_id] = session

        file_type = file_id.file_type

        if file_type == FileType.CHAT_PHOTO:
            if file_id.chat_id > 0:
                peer = raw.types.InputPeerUser(
                    user_id=file_id.chat_id,
                    access_hash=file_id.chat_access_hash
                )
            else:
                if file_id.chat_access_hash == 0:
                    peer = raw.types.InputPeerChat(
                        chat_id=-file_id.chat_id
                    )
                else:
                    peer = raw.types.InputPeerChannel(
                        channel_id=utils.get_channel_id(file_id.chat_id),
                        access_hash=file_id.chat_access_hash
                    )

            location = raw.types.InputPeerPhotoFileLocation(
                peer=peer,
                photo_id=file_id.media_id,
                big=file_id.thumbnail_source == ThumbnailSource.CHAT_PHOTO_BIG
            )
        elif file_type == FileType.PHOTO:
            location = raw.types.InputPhotoFileLocation(
                id=file_id.media_id,
                access_hash=file_id.access_hash,
                file_reference=file_id.file_reference,
                thumb_size=file_id.thumbnail_size
            )
        else:
            location = raw.types.InputDocumentFileLocation(
                id=file_id.media_id,
                access_hash=file_id.access_hash,
                file_reference=file_id.file_reference,
                thumb_size=file_id.thumbnail_size
            )

        current = 0
        total = abs(limit) or (1 << 31) - 1
        chunk_size = 1024 * 1024
        offset_bytes = abs(offset) * chunk_size

        try:
            r = await session.invoke(
                raw.functions.upload.GetFile(
                    location=location,
                    offset=offset_bytes,
                    limit=chunk_size
                ),
                sleep_threshold=30
            )

            if isinstance(r, raw.types.upload.File):
                while True:
                    chunk = r.bytes

                    yield chunk

                    current += 1
                    offset_bytes += chunk_size

                    if progress:
                        func = functools.partial(
                            progress,
                            min(offset_bytes, file_size)
                            if file_size != 0
                            else offset_bytes,
                            file_size,
                            *progress_args
                        )

                        if inspect.iscoroutinefunction(progress):
                            await func()
                        else:
                            await self.loop.run_in_executor(self.executor, func)

                    if len(chunk) < chunk_size or current >= total:
                        break

                    r = await session.invoke(
                        raw.functions.upload.GetFile(
                            location=location,
                            offset=offset_bytes,
                            limit=chunk_size
                        ),
                        sleep_threshold=30
                    )

            elif isinstance(r, raw.types.upload.FileCdnRedirect):
                async with self.media_sessions_lock:
                    cdn_session = self.media_sessions.get(r.dc_id, None)

                    if cdn_session is None:
                        cdn_session = Session(
                            self, r.dc_id, await Auth(self, r.dc_id, await self.storage.test_mode()).create(),
                            await self.storage.test_mode(), is_media=True, is_cdn=True
                        )

                        await cdn_session.start()

                        self.media_sessions[r.dc_id] = cdn_session

                try:
                    while True:
                        r2 = await cdn_session.invoke(
                            raw.functions.upload.GetCdnFile(
                                file_token=r.file_token,
                                offset=offset_bytes,
                                limit=chunk_size
                            )
                        )

                        if isinstance(r2, raw.types.upload.CdnFileReuploadNeeded):
                            try:
                                await session.invoke(
                                    raw.functions.upload.ReuploadCdnFile(
                                        file_token=r.file_token,
                                        request_token=r2.request_token
                                    )
                                )
                            except VolumeLocNotFound:
                                break
                            else:
                                continue

                        chunk = r2.bytes

                        # https://core.telegram.org/cdn#decrypting-files
                        decrypted_chunk = aes.ctr256_decrypt(
                            chunk,
                            r.encryption_key,
                            bytearray(
                                r.encryption_iv[:-4]
                                + (offset_bytes // 16).to_bytes(4, "big")
                            )
                        )

                        hashes = await session.invoke(
                            raw.functions.upload.GetCdnFileHashes(
                                file_token=r.file_token,
                                offset=offset_bytes
                            )
                        )

                        # https://core.telegram.org/cdn#verifying-files
                        for i, h in enumerate(hashes):
                            cdn_chunk = decrypted_chunk[h.limit * i: h.limit * (i + 1)]
                            CDNFileHashMismatch.check(h.hash == sha256(cdn_chunk).digest())

                        yield decrypted_chunk

                        current += 1
                        offset_bytes += chunk_size

                        if progress:
                            func = functools.partial(
                                progress,
                                min(offset_bytes, file_size) if file_size != 0 else offset_bytes,
                                file_size,
                                *progress_args
                            )

                            if inspect.iscoroutinefunction(progress):
                                await func()
                            else:
                                await self.loop.run_in_executor(self.executor, func)

                        if len(chunk) < chunk_size or current >= total:
                            break
                except Exception as e:
                    raise e
        except pyrogram.StopTransmission:
            raise
        except Exception as e:
            log.error(e, exc_info=True)

    def guess_mime_type(self, filename: str) -> Optional[str]:
        return self.mimetypes.guess_type(filename)[0]

    def guess_extension(self, mime_type: str) -> Optional[str]:
        return self.mimetypes.guess_extension(mime_type)


class Cache:
    def __init__(self, capacity: int):
        self.capacity = capacity
        self.store = {}

    def __getitem__(self, key):
        return self.store.get(key, None)

    def __setitem__(self, key, value):
        if key in self.store:
            del self.store[key]

        self.store[key] = value

        if len(self.store) > self.capacity:
            for _ in range(self.capacity // 2 + 1):
                del self.store[next(iter(self.store))]