Locality Social Cloud Chat

locality_social_cloud_chat is a Locality Core based End-to-end-encrypted messaging suite.

Features

• End-to-End-Encryption: Uses ECDH with elliptic Curve M-511 and ChaCha20 for encryption.
• Message Reactions: Users can react to messages with predefined or custom reactions.
• Event-driven Architecture: Respond to specific message types (e.g., text, media) using a PubSub model.
• Group Chats: Invite users to group chats and manage acceptances.
• Efficient UI Updates: Implemented using ThrottledChangeNotifier for optimized state updates.
• Message Observers: Track message states like seen, delivered, and reactions in real-time.

Getting Started

Check the Locality Core to obtain your app realm and secret.

Write

flutter pub add locality_social_cloud_chat
flutter pub get

to import the package. The class 'LocalitySocialCloudChat' provides your interface.

import 'package:locality_core/locality_core.dart';
import 'package:locality_social_cloud_chat/locality_social_cloud_chat.dart';

It provides these methods:

static void setKeyCache(File cache)
static String getCommonTopicForUsers(PublicUser userA, PublicUser userB)
static Future<KeyExchangeLobby> getKeyExchangeLobby(String topic)
static Future<MessagingTopic> getSubscribedTopic(TopicSubscription subscription, ChatMessageFactory chatMessageFactory)
static Future<MessagingTopic> getGroupChat(GroupChatInvitation groupChatInvite, ChatMessageFactory chatMessageFactory)
static Future<MessagingSubscriptions> getUserMessageTopicSubscriptions({required AuthenticatedSessionUser user, String? subTopic, ChaCha20Key? chaChaKey})
static Future<MessagingTopic> getUserChat(AuthenticatedSessionUser loggedInUser, PublicUser publicUser, ChatMessageFactory chatMessageFactory)

Full example

/// A concrete implementation of [ChatMessageFactory] that instantiates [SimpleMessage] from payloads.
class TestChatMessageFactory implements ChatMessageFactory {
  @override
  ChatMessage createFrom(String id, Map<String, dynamic> payload) {
    payload['id'] = id;
    return SimpleMessage.fromMap(payload);
  }
}

void main() async {

  LocalitySocialCloud cloud = await LocalitySocialCloud.startTest(
      userCredentials: UserCredentials("userId", "password"),
      developerCredentials: DeveloperCredentials(
          realmId: "ptr2",
          realmSecret: "h3w1uzXhmHc4JvZi6ZE6bGXlPPISH/t26Pb6vtGzffE="
      ),
      isRegistration: true
  );

  AuthenticatedSessionUser authenticatedSessionUser = cloud.getLoggedInUser();
  LocalitySocialCloudChat localitySocialCloudChat;

  KeyExchangeLobby keyExchangeLobby = await LocalitySocialCloudChat.getKeyExchangeLobby("hello");
  if ( !keyExchangeLobby.containsMe(authenticatedSessionUser) ) {
    keyExchangeLobby.announcePresence(authenticatedSessionUser);
  }
  // We want to message this user
  PublicUser? klaus = keyExchangeLobby.getUserById("KLAUS");

  if ( klaus != null ) {
    // Klaus announced his presence, so we can message him
    MessagingTopic messagingTopic = await LocalitySocialCloudChat.getUserChat(authenticatedSessionUser, klaus, TestChatMessageFactory());
    messagingTopic.sendMessage(SimpleMessage(user: authenticatedSessionUser, message: "HELLO BONJOUR KLAUS"));
  }

  MessagingSubscriptions messagingSubscriptions = await LocalitySocialCloudChat.getUserMessageTopicSubscriptions(user: authenticatedSessionUser);
  messagingSubscriptions.subscriptions.values.forEach((subscription) =>
      // Will connect to all messaging topics
      LocalitySocialCloudChat.getSubscribedTopic(subscription, TestChatMessageFactory())
  );
}