mtflute 0.2.2

Pure-Dart Telegram MTProto client (API layer 227) with a built-in HTTP streaming engine for mediakit / video players.

mtflute

Pure-Dart Telegram MTProto client with a built-in HTTP streaming engine for mediakit / video_player / any Range-aware HTTP consumer. Talks directly to Telegram's servers like Telethon / Pyrogram / gogram — no Bot API, no native libs.

Currently against Telegram API layer 227 (TDesktop dev).

Highlights

• Streaming engine: TelegramFileStreamServer.publishMessage(peer, msgId) returns a http://127.0.0.1:PORT/f/... URL you feed straight into mediakit. Full HTTP Range 206, seek-aware prefetch, per-entry LRU chunk cache, per-request cancellation on disconnect, CORS.
• Cached location resolver: MediaLocationCache keyed by (peerId, msgId) so repeated stream requests skip the source-message fetch. Auto-refreshes on FILE_REFERENCE_EXPIRED.
• Auth: bot tokens, phone + OTP + 2FA (SRP), string sessions (gogram-compatible 1BvE format), file sessions.
• Session + peer persistence: peer cache (users, channels, usernames) auto-saved into the session file, reloaded on next start — no re-resolve after app restart. Atomic writes, async debounced flush, guaranteed on close(). 5.6× reuse-login speedup.
• Files: parallel workers with cached cross-DC senders, downloadStream / downloadRange, transparent FILE_MIGRATE + FILE_REFERENCE_EXPIRED, FLOOD_WAIT respected, bounded retries.
• Reconnect: single-flight, exponential backoff with jitter, idle-detect after Android background (>90s), transparent recovery on bad_msg (16/17/32/33/48) and bad_server_salt.
• Messaging: send/edit/delete/forward/pin, Markdown + HTML parse modes, inline button builder.
• Updates: socket push + getDifference polling with FLOOD_WAIT backoff, dedup (16k msg IDs).
• Conversation API: client.conversation(peer).ask('Name?').
• Android / Flutter safe: only dart:io, no isolates / mirrors / ffi. Ships with a TgEngine reference wrapper.

Streaming quickstart (Flutter Android)

import 'package:mtflute/mtflute.dart';
import 'package:path_provider/path_provider.dart';
import 'package:media_kit/media_kit.dart';

final docs = await getApplicationDocumentsDirectory();
final client = MtpClient(
  appId: YOUR_API_ID,
  appHash: 'YOUR_API_HASH',
  dcId: 4,
  sessionFile: '${docs.path}/mtflute.session',
);
await client.loginBot('123:ABC-bot-token');

final server = TelegramFileStreamServer(client);
await server.start();
await server.warmup(dcId: client.dcId, workers: 4);

// One line to hand a message's media to any HTTP player:
final url = await server.publishMessage(peer: peer, msgId: msgId);

Player().open(Media(url));

The server serves HTTP Range 206 with byte-exact content. mediakit / libmpv seeks work out of the box.

See example/flutter_engine.dart for the full TgEngine singleton pattern.

Bot quickstart

final client = MtpClient(
  appId: YOUR_API_ID,
  appHash: 'YOUR_API_HASH',
  sessionFile: 'bot.session',
);
await client.loginBot('123:ABC-bot-token');

client.onMessage((msg) async {
  if (msg.text == '/start') {
    await msg.reply(
      '**Hi!** Tap a button:',
      parseMode: 'md',
      buttons: (Keyboard()
            ..row([Button.callback('Yes', 'cb:yes'), Button.url('Docs', 'https://t.me')]))
          .inline(),
    );
  }
});

client.onCallbackQuery((cq) async {
  await cq.answer(message: 'You picked it!');
});

await client.idle();

User quickstart

final client = MtpClient(
  appId: YOUR_API_ID,
  appHash: 'YOUR_API_HASH',
  sessionFile: 'user.session',
);

await client.login(
  codeCallback: (prompt) async { stdout.write(prompt); return stdin.readLineSync()!; },
  passwordCallback: (prompt) async { stdout.write(prompt); return stdin.readLineSync()!; },
);

On Android/iOS the stdin prompt path throws — pass your own callbacks (SMS text field, dialog, etc.).

Files

// Send a local file
await client.sendFile(
  peer: peer,
  file: File('photo.jpg'),
  caption: 'caption',
  onProgress: (cur, total) => print('${cur * 100 ~/ total}%'),
);

// Whole-file download
await client.downloadToFile(location, 'out.bin', dcId: 4, size: 12345);

// Streaming download (chunk-by-chunk, no full-file buffering)
await for (final chunk in client.downloadStream(location, dcId: 4, size: 12345)) {
  // ... write chunk somewhere
}

// Arbitrary byte range
final bytes = await client.downloadRange(location, start: 1_000_000, end: 2_000_000, dcId: 4);

// From a chat message (uses MediaLocationCache under the hood)
final url = await server.publishMessage(peer: peer, msgId: msgId);

Conversation

final conv = client.conversation(peer);
final reply = await conv.ask("What's your name?");
await conv.respond('Hi ${reply.text}!');
conv.close();

Sessions

// File session — reloaded automatically on next construct
final client = MtpClient(
  appId: id, appHash: hash,
  sessionFile: '${docs.path}/mtflute.session',
);

// String session (gogram-compatible byte format)
final s = client.exportSession();          // -> "1BvEeyJrZXkiOi..."
final restored = MtpClient(
  appId: id, appHash: hash, stringSession: s,
);

Peer cache (users, channels, usernames + access hashes) is persisted alongside the auth key in the session file — no re-resolve after app restart.

Status

v0.2.0 — streaming engine release, 3 rounds of adversarial audit, 18/18 live checks passing.

APIs are largely stable; PRs welcome.