dimp 2.2.1

Decentralized Instant Messaging Protocol (DIMP).

Decentralized Instant Messaging Protocol (Dart)

Dependencies

Name	Version	Description
Ming Ke Ming (名可名)		Decentralized User Identity Authentication
Dao Ke Dao (道可道)		Universal Message Module

Examples

Extends Command

• Handshake Command Protocol
  0. (C-S) handshake start
  1. (S-C) handshake again with new session
  2. (C-S) handshake restart with new session
  3. (S-C) handshake success

import 'package:dimp/protocol.dart';


class HandshakeState {

  static const int START   = 0;  // C -> S, without session key(or session expired)
  static const int AGAIN   = 1;  // S -> C, with new session key
  static const int RESTART = 2;  // C -> S, with new session key
  static const int SUCCESS = 3;  // S -> C, handshake accepted

  static int checkState(String title, String? session) {
    if (title == 'DIM!'/* || title == 'OK!'*/) {
      return SUCCESS;
    } else if (title == 'DIM?') {
      return AGAIN;
    } else if (session == null) {
      return START;
    } else {
      return RESTART;
    }
  }
}


///  Handshake command: {
///      type : i2s(0x88),
///      sn   : 123,
///
///      command : "handshake",    // command name
///      title   : "Hello world!", // "DIM?", "DIM!"
///      session : "{SESSION_KEY}" // session key
///  }
abstract interface class HandshakeCommand implements Command {

  static const String HANDSHAKE = 'handshake';

  String get title;
  String? get sessionKey;

  int get state;

  static HandshakeCommand start() =>
      BaseHandshakeCommand.from('Hello world!');

  static HandshakeCommand restart(String session) =>
      BaseHandshakeCommand.from('Hello world!', sessionKey: session);

  static HandshakeCommand again(String session) =>
      BaseHandshakeCommand.from('DIM?', sessionKey: session);

  static HandshakeCommand success(String? session) =>
      BaseHandshakeCommand.from('DIM!', sessionKey: session);

}


class BaseHandshakeCommand extends BaseCommand implements HandshakeCommand {
  BaseHandshakeCommand(super.dict);

  BaseHandshakeCommand.from(String title, {String? sessionKey})
      : super.fromName(HandshakeCommand.HANDSHAKE) {
    // text message
    this['title'] = title;
    // session key
    if (sessionKey != null) {
      this['session'] = sessionKey;
    }
  }

  @override
  String get title => getString('title') ?? '';

  @override
  String? get sessionKey => getString('session');

  @override
  int get state => HandshakeState.checkState(title, sessionKey);

}

Extends Content

import 'package:dimp/protocol.dart';


///  Application Customized message: {
///      type : i2s(0xA0),
///      sn   : 123,
///
///      app   : "{APP_ID}",  // application (e.g.: "chat.dim.sechat")
///      extra : info         // others
///  }
class ApplicationContent extends BaseContent implements AppContent {
  ApplicationContent(super.dict);

  ApplicationContent({required String app}) : super.fromType(ContentType.APPLICATION) {
    this['app'] = app;
  }

  @override
  String get application => getString('app') ?? '';

}

Extends ID Address

• Examples in dim_plugins

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