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Telethon is Telegram client implementation in Python which uses the latest available API of Telegram.

Before opening an issue about how to use the library, please make sure you have read and followed the steps mentioned under Using Telethon and are using the latest version! A lot of people ask simple questions which will only be answered as "please see the README.rst". And you should use the search before posting an issue, too.

If you come here often, you may want to go to the docs.

Why should I bother with Telethon? There are more mature projects already, such as telegram-cli with even (limited) Python support. And we have the official clients!

With Telethon you don't really need to know anything before using it. Create a client with your settings. Connect. You're ready to go.

Being written entirely on Python, Telethon can run as a script under any environment you wish, (yes, Android too). You can schedule it, or use it in any other script you have. Want to send a message to someone when you're available? Write a script. Do you want check for new messages at a given time and find relevant ones? Write a script.

Hungry for more API calls which the TelegramClient class doesn't seem to have implemented? Please read Using more than just TelegramClient.

In order to use Telethon, you first need to obtain your very own API ID and Hash:

1. Follow this link and login with your phone number.
2. Click under API Development tools.
3. A Create new application window will appear. Fill in your application details. There is no need to enter any URL, and only the first two fields (App title and Short name) can be changed later as long as I'm aware.
4. Click on Create application at the end.

Now that you know your API ID and Hash, you can continue installing Telethon.

On a terminal, issue the following command:

sudo -H pip install telethon

If you get something like "SyntaxError: invalid syntax" on the from error line, it's because pip defaults to Python 2. Use pip3 instead.

If you already have Telethon installed, upgrade with pip install --upgrade telethon!

1. Install the required pyaes module: sudo -H pip install pyaes (GitHub, package index)
2. Clone Telethon's GitHub repository: git clone https://github.com/LonamiWebs/Telethon.git
3. Enter the cloned repository: cd Telethon
4. Run the code generator: python3 setup.py gen_tl
5. Done!

If you've installed Telethon via pip, launch an interactive python3 session and enter the following:

>>> from telethon import TelegramClient
>>> api_id = 12345
>>> api_hash = '0123456789abcdef0123456789abcdef'
>>> # 'session_id' can be 'your_name'. It'll be saved as your_name.session
... client = TelegramClient('session_id', api_id, api_hash)
>>> client.connect()
True
>>>
>>> if not client.is_user_authorized():
>>>   client.send_code_request(' 34600000000')
>>>   client.sign_in(' 34600000000', input('Enter code: '))
...
>>> # Now you can use the connected client as you wish
>>> dialogs, entities = client.get_dialogs(10)
>>> print('\n'.join('{}. {}'.format(i, str(e))
...                 for i, e in enumerate(entities)))

If, on the other hand, you've installed Telethon manually, head to the api/ directory and create a copy of the settings_example file, naming it settings (lowercase!). Then fill the file with the corresponding values (your api_id, api_hash and phone number in international format).

Then, simply run ./try_telethon.py to start the interactive example.

If you really want to learn how to use Telethon, it is highly advised that you take a look to the InteractiveTelegramClient file and check how it works. This file contains everything you'll need to build your own application, since it shows, among other things:

1. Authorizing the user for the first time.
2. Support to enter the 2-steps-verification code.
3. Retrieving dialogs (chats) and the messages history.
4. Sending messages and files.
5. Downloading files.
6. Updates thread.

If you want a nicer way to see all the available requests and types at your disposal, please check the official Telethon documentation. There you'll find a list of all the methods, types and available constructors.

More examples are also available under the telethon_examples/ folder.

Errors resulting from Telegram queries all subclass the RPCError class. This class is further specialized into further errors:

• InvalidDCError (303), the request must be repeated on another DC.
• BadRequestError (400), the request contained errors.
• UnauthorizedError (401), the user is not authorized yet.
• ForbiddenError (403), privacy violation error.
• NotFoundError (404), make sure you're invoking Request's!
• FloodError (420), the same request was repeated many times. Must wait .seconds.

Further specialization is also available, for instance, the SessionPasswordNeededError when signing in means that a password must be provided to continue.

If the error is not recognised, it will only be an RPCError.

Unless you know what you're doing, you should download media by always using the .download_file() function, which supports a str or a file handle as parameters. Otherwise, .invoke() may raise InvalidDCError which you will have to handle, and in turn call .invoke_on_dc() manually.

The TelegramClient class should be used to provide a quick, well-documented and simplified starting point. It is not meant to be a place for all the available Telegram Request's, because there are simply too many.

However, this doesn't mean that you cannot invoke all the power of Telegram's API. Whenever you need to call a Telegram Request, all you need to do is the following:

result = client(SomeRequest(...))

# Or the old way:
result = client.invoke(SomeRequest(...))

You have just called SomeRequest and retrieved its result! That wasn't hard at all, was it? Now you may wonder, what's the deal with all the power of Telegram's API? Have a look under tl/functions/. That is everything you can do. You have over 200 API Request's at your disposal.

However, we don't pretty know how that result looks like. Easy. print(str(result)) should give you a quick overview. Nevertheless, there may be more than a single result! Let's have a look at this seemingly innocent TL definition:

messages.getWebPagePreview#25223e24 message:string = MessageMedia;

Focusing on the end, we can see that the result of invoking GetWebPagePreviewRequest is MessageMedia. But how can MessageMedia exactly look like? It's time to have another look, but this time under tl/types/:

$ tree -P "message_media_*"
.
├── tl
│   └── types
│       ├── message_media_contact.py
│       ├── message_media_document.py
│       ├── message_media_empty.py
│       ├── message_media_geo.py
│       ├── message_media_photo.py
│       ├── message_media_unsupported.py
│       ├── message_media_venue.py
│       └── message_media_web_page.py

Those are eight different types! How do we know what exact type it is to determine its properties? A simple if type(result) == MessageMediaContact: or similar will do. Now you're ready to take advantage of Telegram's polymorphism.

First of all, you need to understand how the scheme.tl (TL language) works. Every object definition is written as follows:

name#id argument_name:argument_type = CommonType

This means that in a single line you know what the TLObject name is. You know it's unique ID, and you know what arguments it has. It really isn't that hard to write a generator for generating code to any platform!

The generated code should also be able to encode the Request into bytes, so they can be sent over the network. This isn't a big deal either, because you know how the TLObject's are made.

Once you have your own code generator, start by looking at the first release of Telethon. The code there is simple to understand, easy to read and hence easy to port. No extra useless features. Only the bare bones. Perfect for starting a new implementation.

P.S.: I may have lied a bit. The TL language is not that easy. But it's not that hard either. You're free to sniff the parser/ files and learn how to parse other more complex lines. Or simply use that code and change the SourceBuilder!

The code generator will skip the types considered as core types. These types are usually included in almost every programming language, such as boolean values or lists, and also the Telegram True flag, which is not sent but rather used to determine whether that flag should be enabled or not.

Have you found a more updated version of the scheme.tl file? Those are great news! Updating is as simple as grabbing the latest version and replacing the one you can find in this same directory by the updated one. Don't forget to run python3 setup.py gen_tl.

If the changes weren't too big, everything should still work the same way as it did before; but with extra features.

If you want to use Telethon via proxy, you have to install PySocks (via pip or manual). Once this is done, pass the proxy settings to the TelegramClient constructor:

>>> from telethon import TelegramClient
>>> import socks
>>> client = TelegramClient('session_id',
...     api_id=12345, api_hash='0123456789abcdef0123456789abcdef',
...     proxy=(socks.SOCKS5, 'localhost', 4444))

The proxy= argument should be a tuple, a list or a dict, consisting of parameters described here.