技术问询：无需订阅通过joinchat链接读取Telegram频道消息（Telethon）

Great question! Since you’ve confirmed you can view the channel’s full messages on Telegram’s mobile app without subscribing, this means the channel allows guest/unsubscribed access—and yes, you absolutely can replicate this with Telethon.

How It Works #

Telegram’s API treats guest access to these channels the same way the official app does: as long as you can resolve the channel’s entity (via the joinchat link), you can fetch messages without needing to subscribe. Here’s how to implement it step by step:

Step 1: Get Your Telegram API Credentials #

You’ll need an API ID and API Hash to interact with Telegram’s API. You can get these by registering a new app on Telegram’s official developer platform (it’s free and takes just a couple of minutes).

Step 2: Resolve the joinchat Link to the Channel Entity #

Telethon’s get_entity() method can take your joinchat URL directly and resolve it to the corresponding channel object, even if you aren’t subscribed. This works because the link grants you temporary guest access to the channel.

Step 3: Fetch Messages from the Channel #

Once you have the channel entity, use Telethon’s get_messages() method to retrieve messages just like you would for a subscribed channel.

Full Example Code #

from telethon import TelegramClient
import asyncio

# Replace these with your actual API credentials
API_ID = 123456
API_HASH = "your_api_hash_here"
SESSION_NAME = "guest_channel_reader"
JOINCHAT_LINK = "https://t.me/joinchat/AAA..."  # Your target joinchat link

async def fetch_guest_messages():
    async with TelegramClient(SESSION_NAME, API_ID, API_HASH) as client:
        try:
            # Resolve the joinchat link to the channel entity
            channel = await client.get_entity(JOINCHAT_LINK)
            print(f"Successfully accessed channel: {channel.title}")
            
            # Fetch the latest 20 messages (adjust the limit as needed)
            messages = await client.get_messages(channel, limit=20)
            
            print("\nLatest messages from the channel:")
            for count, msg in enumerate(messages, 1):
                # Handle text and non-text messages (like photos/videos)
                content = msg.text if msg.text else "[Media attachment]"
                print(f"{count}. {content}")
        
        except Exception as e:
            print(f"Error occurred: {str(e)}")
            print("This could mean the channel restricts guest access, your API credentials are invalid, or the link is expired.")

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

Key Notes to Keep in Mind #

• Permission Limits: If you get a "permission denied" error, the channel likely doesn’t actually allow guest access—even if you thought it did. Sometimes the mobile app auto-subscribes you when you open the link without explicit confirmation.
• Rate Limits: Always respect Telegram’s API rate limits. Avoid sending too many requests in a short period, as this can lead to temporary account restrictions.
• Telethon Updates: Make sure you’re using the latest version of Telethon (run pip install --upgrade telethon to update) to avoid compatibility issues with Telegram’s API.

内容的提问来源于stack exchange，提问作者Mikhail Volovik