td

A fast Telegram client in pure Go.

Before using this library, read How To Not Get Banned guide.

Due to limitations of pkg.go.dev, documentation for tg package is not shown, but there is hosted version.

Usage

go get github.com/gotd/td

package main

import (
	"context"

	"github.com/gotd/td/telegram"
)

func main() {
	// https://core.telegram.org/api/obtaining_api_id
	client := telegram.NewClient(appID, appHash, telegram.Options{})
	if err := client.Run(context.Background(), func(ctx context.Context) error {
		// It is only valid to use client while this function is not returned
		// and ctx is not cancelled.
		api := client.API()

		// Now you can invoke MTProto RPC requests by calling the API.
		// ...

		// Return to close client connection and free up resources.
		return nil
	}); err != nil {
		panic(err)
	}
	// Client is closed.
}

See examples for more info.

Features

Full MTProto 2.0 implementation in Golang, directly access any MTProto method with telegram.Client.API()
Highly optimized, low memory (150kb per idle client) and CPU overhead, can handle thousands concurrent clients
Code for Telegram types generated by ./cmd/gotdgen (based on gotd/tl parser) with embedded official documentation
Pluggable session storage
Automatic re-connects with keepalive
Vendored Telegram public keys that are kept up-to-date
Rigorously tested
- End-to-end with real Telegram server in CI
- End-to-end with gotd Telegram server (in pure Go)
- Lots of unit testing
- Fuzzing
- 24/7 canary bot in production that tests reconnects, update handling, memory leaks and performance
No runtime reflection overhead
Conforms to Security guidelines for Telegram client software developers
- Secure PRNG used for crypto
- Replay attack protection
2FA support
MTProxy support
Various helpers that lighten the complexity of the Telegram API
- uploads for big and small files with multiple streams for single file and progress reporting
- downloads with CDN support, also multiple streams
- messages with various convenience builders and text styling support
- query with pagination helpers
- middleware for rate limiting and FLOOD_WAIT handling
Connection pooling
Automatic datacenter migration and redirects handling
Graceful request cancellation via context
WebSocket transport support (works in WASM)

Status

The goal of this project is to implement a stable, performant and safe client for Telegram in pure Go while having a simple and convenient API and a feature parity with TDLib.

This project is fully non-commercial and not affiliated with any commercial organization (including Telegram LLC).

Examples

See examples directory.

Also take a look at

gotd/bot with updates recovery enabled, used as canary for stability testing
gotd/cli, command line interface for subset of telegram methods.

Auth

User

You can use td/telegram/auth.Flow to simplify user authentications.

codePrompt := func(ctx context.Context, sentCode *tg.AuthSentCode) (string, error) {
    // NB: Use "golang.org/x/crypto/ssh/terminal" to prompt password.
    fmt.Print("Enter code: ")
    code, err := bufio.NewReader(os.Stdin).ReadString('\n')
    if err != nil {
        return "", err
    }
    return strings.TrimSpace(code), nil
}
// This will setup and perform authentication flow.
// If account does not require 2FA password, use telegram.CodeOnlyAuth
// instead of telegram.ConstantAuth.
if err := auth.NewFlow(
    auth.Constant(phone, password, auth.CodeAuthenticatorFunc(codePrompt)),
    auth.SendCodeOptions{},
).Run(ctx, client.Auth()); err != nil {
    panic(err)
}

Bot

Use bot token from @BotFather.

if err := client.Auth().Bot(ctx, "token:12345"); err != nil {
    panic(err)
}

Calling MTProto directly

You can use the generated tg.Client that allows calling any MTProto method directly.

// Grab these from https://my.telegram.org/apps.
// Never share it or hardcode!
client := telegram.NewClient(appID, appHash, telegram.Options{})
client.Run(ctx, func(ctx context.Context) error {
  // Grab token from @BotFather.
  if _, err := client.Auth().Bot(ctx, "token:12345"); err != nil {
    return err
  }
  state, err := client.API().UpdatesGetState(ctx)
  if err != nil {
    return err
  }
  // Got state: &{Pts:197 Qts:0 Date:1606855030 Seq:1 UnreadCount:106}
  // This will close client and cleanup resources.
  return nil
})

Generated code

The code output of gotdgen contains references to TL types, examples, URL to official documentation and extracted comments from it.

For example, the auth.Authorization type in tg/tl_auth_authorization_gen.go:

// AuthAuthorizationClass represents auth.Authorization generic type.
//
// See https://core.telegram.org/type/auth.Authorization for reference.
//
// Example:
//  g, err := DecodeAuthAuthorization(buf)
//  if err != nil {
//      panic(err)
//  }
//  switch v := g.(type) {
//  case *AuthAuthorization: // auth.authorization#cd050916
//  case *AuthAuthorizationSignUpRequired: // auth.authorizationSignUpRequired#44747e9a
//  default: panic(v)
//  }
type AuthAuthorizationClass interface {
	bin.Encoder
	bin.Decoder
	construct() AuthAuthorizationClass
}

Also, the corresponding auth.signIn method:

// AuthSignIn invokes method auth.signIn#bcd51581 returning error if any.
// Signs in a user with a validated phone number.
//
// See https://core.telegram.org/method/auth.signIn for reference.
func (c *Client) AuthSignIn(ctx context.Context, request *AuthSignInRequest) (AuthAuthorizationClass, error) {}

The generated constructors contain detailed official documentation, including links:

// FoldersDeleteFolderRequest represents TL type `folders.deleteFolder#1c295881`.
// Delete a peer folder¹
//
// Links:
//  1) https://core.telegram.org/api/folders#peer-folders
//
// See https://core.telegram.org/method/folders.deleteFolder for reference.
type FoldersDeleteFolderRequest struct {
    // Peer folder ID, for more info click here¹
    //
    // Links:
    //  1) https://core.telegram.org/api/folders#peer-folders
    FolderID int
}

Contributions

Huge thanks to all contributors. Dealing with a project of this scale alone is impossible.

Special thanks:

tdakkota
- Two-factor authentication (SRP)
- Proxy support
- Update dispatcher
- Complete transport support (abridged, padded intermediate and full)
- Telegram server for end-to-end testing
- Multiple major refactorings, including critical cryptographical scope reduction
- Code generation improvements (vector support, multiple modes for pretty-print)
- And many other cool things and performance improvements
shadowspore
- Background pings
- Links in generated documentation
- Message acknowledgements
- Retries
- RPC Engine
- Gap (Updates) engine

Reference

The MTProto protocol description is hosted by Telegram.

Most important parts for client implementations:

Security guidelines for client software developers

Current implementation mostly conforms to security guidelines, but no formal security audit were performed.

Prior art

Lonami/grammers (Great Telegram client in Rust, many test vectors were used as reference)
sdidyk/mtproto, cjongseok/mtproto, xelaj/mtproto (MTProto 1.0 in go)

Who is using gotd?

Drop a comment here to add your project.

License

MIT License

Created by Aleksandr (ernado) Razumov

2020

sanengineer / td

td