如何在现有Telethon代码中正确使用FastTelethonHelper的fast_download？

你的核心问题是现有代码用了同步版Telethon，但fast_download是异步函数必须用await调用，所以需要把整个代码切换到异步模式，以下是修改后的完整可运行代码：

import asyncio
from telethon import TelegramClient
from telethon.tl.functions.messages import GetDialogsRequest
from telethon.tl.functions.channels import GetFullChannelRequest
from FastTelethonhelper import fast_download
from telethon.tl.types import InputPeerEmpty
from tqdm import tqdm

api_id = 你的api_id  # 填入实际api_id
api_hash = '你的api_hash'  # 填入实际api_hash


def callback(current, total):
    global pbar
    global prev_curr
    pbar.update(current - prev_curr)
    prev_curr = current


async def download_media(group, cl, name):
    global pbar
    global prev_curr

    # 异步获取消息，必须加await
    messages = await cl.get_messages(group, limit=2000)

    start = 0
    print(start)
    for i, message in enumerate(messages[start:]):
        prev_curr = 0
        if message.video:
            print(f"\n{i + start} / {len(messages)} : {message.file.name}")
            pbar = tqdm(total=message.document.size, unit='B', unit_scale=True)
            # 替换原同步download_media为异步fast_download，加await
            await fast_download(
                client=cl,
                file=message.video,
                download_folder=f'./{name}/',
                progress_bar_function=callback
            )
            pbar.close()


async def main():
    async with TelegramClient('name', api_id, api_hash) as client:
        result = await client(GetDialogsRequest(
            offset_date=None,
            offset_id=0,
            offset_peer=InputPeerEmpty(),
            limit=500,
            hash=0,
        ))

        title = 'channel_name'  # 填入目标频道名称
        channel = await client(GetFullChannelRequest(title))
        await download_media(channel.full_chat, client, "directory_name")


if __name__ == "__main__":
    asyncio.run(main())

关键修改说明： #

• 切换异步客户端：移除telethon.sync导入，改用标准telethon.TelegramClient，所有客户端方法（如get_messages、调用GetFullChannelRequest）都需要加await
• 异步函数改造：把download_media改成async def，主逻辑封装到main异步函数中，用asyncio.run启动
• fast_download调用：给fast_download加await关键字，参数保持和你注释里的一致，注意file参数传入message.video是正确的
• 全局变量保留：暂时保留了你原来的全局pbar和prev_curr，如果想优化可以改成函数内的非局部变量，避免全局污染

额外优化建议： #

去掉全局变量，把pbar和prev_curr放到download_media函数内，避免多消息下载时的状态冲突：

async def download_media(group, cl, name):
    messages = await cl.get_messages(group, limit=2000)
    start = 0
    print(start)
    for i, message in enumerate(messages[start:]):
        if message.video:
            print(f"\n{i + start} / {len(messages)} : {message.file.name}")
            prev_curr = 0
            pbar = tqdm(total=message.document.size, unit='B', unit_scale=True)
            def callback(current, total):
                nonlocal prev_curr
                pbar.update(current - prev_curr)
                prev_curr = current
            await fast_download(
                client=cl,
                file=message.video,
                download_folder=f'./{name}/',
                progress_bar_function=callback
            )
            pbar.close()

内容的提问来源于stack exchange，提问作者Kthway