# Core

> The core package implementing the Control Plane and Mediator SDK, including managing multiple digital identities for better privacy and anonymity in digital interactions.

## Install Dependency

Package: meeting_place_core

```bash
dart pub add meeting_place_core
```

Check the latest version on the [pub.dev registry](https://pub.dev/packages/meeting_place_core) or view the source on [GitHub](https://github.com/affinidi/affinidi-meetingplace-sdk-dart/tree/main/packages/meeting_place_core).

## Classes and Methods

### MeetingPlaceCoreSDK

The MeetingPlaceCoreSDK is the main orchestrator for the Affinidi Meeting Place ecosystem, providing a high-level interface for connection setup, discovery, and secure decentralised communications through control plane and mediator services.

#### create

A static method that creates an instance of CoreSDK. For each connection, it requires the creation of an instance of CoreSDK.

Parameters

    wallet
    Wallet
    Required

A digital wallet to manage cryptographic keys supporting different algorithms for signing and verifying VC and VP.

This requires the installation of the SSI package from [pub.dev](https://pub.dev/packages/ssi).

    repositoryConfig
    RepositoryConfig
    Required
  A repository object which defines the storage, group, key and channel repository objects.

    config
    Config
    Required
  Configuration object containing the required DID endpoints. Pass mediatorDid (the mediator DID including the .well-known path) and controlPlaneDid (the control plane DID) inside this object.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final wallet = Bip32Wallet.fromSeed(aliceSeed);
final storage = InMemoryStorage();

final mediatorDid = ':.well-known';
final controlPlaneDid = '';

final sdk = await MeetingPlaceCoreSDK.create(
    wallet: wallet,
    repositoryConfig: RepositoryConfig(
        connectionOfferRepository: ConnectionOfferRepositoryImpl(storage: storage),
        groupRepository: GroupRepositoryImpl(storage: storage),
        channelRepository: ChannelRepositoryImpl(storage: storage),
        keyRepository: KeyRepositoryImpl(storage: storage),
    ),
    config: Config(
        mediatorDid: mediatorDid,
        controlPlaneDid: controlPlaneDid,
    ),
  );
```

#### generateDid

An instance method that generates a new DID using the provided [Wallet] instance.

Parameters

No parameters required.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final sdk = await MeetingPlaceCoreSDK.create(
    wallet: wallet,
    ...
);

final did = await sdk.generateDid();
```

#### createOobFlow

An instance method that creates an Out-Of-Band invitation for an entity.

Parameters

    contactCard
    ContactCard
    Required
  An object that contains information about who is creating the invitation. This helps others know whom they are connecting with.

    type
    String
    Optional
  Optional channel type identifier.

    mediatorDid
    String
    Optional
  Optional mediator DID override. Defaults to the SDK instance’s configured mediator DID.

    externalRef
    String
    Optional
  Optional application-specific reference stored locally for tracking purposes.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    wallet: wallet,
    ...
);

final createOobFlowResult = await aliceSDK.createOobFlow(
    contactCard: ContactCard(values: {
      'n': {'given': 'Alice'},
    }),
);
```

#### acceptOobFlow

An instance method that accepts an Out-Of-Band invitation created by an entity. This is typically used by the party receiving the invitation to establish a connection.

Parameters

    oobUrl
    Uri
    Required
  The OOB invitation URL created by createOobFlow.

    contactCard
    ContactCard
    Required
  An object that contains information about who is accepting the invitation.

    type
    String
    Optional
  Optional channel type identifier.

    externalRef
    String
    Optional
  Optional application-specific reference stored locally for tracking purposes.

    attachments
    List<Attachment>
    Optional
  Optional list of attachments (for example, R-Card credentials) to include in the acceptance message.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final bobSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final createOobFlowResult = await aliceSDK.createOobFlow(
    contactCard: ContactCard(values: {
      'n': {'given': 'Alice'},
    }),
);

await bobSDK.acceptOobFlow(
    createOobFlowResult.oobUrl,
    contactCard: ContactCard(values: {
      'n': {'given': 'Bob'},
    }),
);
```

#### validateOfferPhrase

An instance method that validates whether a given offer phrase is already in use within the system. This returns a response with an isAvailable flag that shows whether the offer phrase is available or already in use.

Parameters

    phrase
    string
    Required
  The offer phrase to be checked for availability.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final offerPhraseResult = await aliceSDK.validateOfferPhrase('');
```

#### registerForPushNotifications

An instance method that registers the device for push notifications using the provided deviceToken from the OS-native push notification service, which will be used to notify the device about events in the Meeting Place flow and automatically included in subsequent API calls.

Parameters

    deviceToken
    string
    Required
  The device token obtained from the operating system’s native push notification service.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final deviceInstance = aliceSDK.registerForPushNotifications('');
```

#### registerForDIDCommNotifications

An instance method that registers the device for push notifications using the provided deviceToken from the OS-native push notification service, which will be used to notify the device about events in the Meeting Place flow and automatically included in subsequent API calls.

Parameters

No parameters required.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final registerForDidcommNotificationsResult = aliceSDK.registerForDIDCommNotifications();
```

#### publishOffer

An instance method that publishes an offer on MeetingPlace. This method allows a user to create and share an offer that others can discover and connect with.

Parameters

    offerName
    string
    Required
  The name of your offer as it will be displayed when others search for offers.

    contactCard
    ContactCard
    Required
  An object that contains information about who is publishing the offer. This helps others know whom they are connecting with.

    offerDescription
    string
    Required
  A description of the offer displayed to others who discover it.

    type
    SDKConnectionOfferType
    Required
  The offer type. Use SDKConnectionOfferType.meetingPlaceInvitation for a personal offer or SDKConnectionOfferType.groupInvitation for a group offer.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final publishOfferResult = await aliceSDK.publishOffer(
    offerName: 'SDK Offer',
    offerDescription: 'Connect with Alice on Meeting Place.',
    type: SDKConnectionOfferType.meetingPlaceInvitation,
    contactCard: ContactCard(values: {
      'n': {'given': 'Alice'},
    }),
);
```

#### findOffer

An instance method that finds an offer published by another party using a unique mnemonic identifier.

Parameters

    mnemonic
    string
    Required
  The unique mnemonic identifier used to search for the offer.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final bobSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final menmonic = '';
final offerResult = await bobSDK.findOffer(mnemonic);
```

#### acceptOffer

An instance method that accepts a connection offer published by another party. This method allows a user to respond to an offer and establish a connection request.

Parameters

    connectionOffer
    Object
    Required
  A connection offer object.

    contactCard
    ContactCard
    Required
  An object that contains information about who is accepting the offer. This helps the offeree know who accepted.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final bobSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final menmonic = '';
final offerResult = await bobSDK.findOffer(mnemonic);

final offerAcceptedResult = await bobSDK.acceptOffer(
    connectionOffer: offerResult.connectionOffer!,
    contactCard: ContactCard(values: {
      'n': {'given': 'Bob'},
    }),
);
```

#### notifyAcceptance

An instance method that notifies the owner of the offer about the acceptance of their connection offer.

Parameters

    connectionOffer
    Object
    Required
  ConnectionOffer object in the ‘accepted’ state.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final bobSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final menmonic = '';
final offerResult = await bobSDK.findOffer(mnemonic);

final offerAcceptedResult = await bobSDK.acceptOffer(
    connectionOffer: offerResult.connectionOffer!,
    contactCard: ContactCard(values: {
      'n': {'given': 'Bob'},
    }),
);

await bobSDK.notifyAcceptance(
    connectionOffer: offerAcceptedResult.connectionOffer,
);
```

#### approveConnectionRequest

An instance method to allow the owner of the offer to approve a connection request.

Parameters

    connectionOffer
    Object
    Required
  [GroupConnectionOffer] object for group.

    channel
    Object
    Required
  Channel object.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

aliceSDK.discoveryEventsStream.listen((event) async {
    if (event.type.name == DiscoveryEventType.InvitationAccept.name) {
        await aliceSDK.approveConnectionRequest(
            connectionOffer: publishOfferResult.connectionOffer,
            channel: event.channel,
        );
    }
});
```

#### rejectConnectionRequest

An instance method to allow the owner of the offer to reject a connection request.

Parameters

    channel
    Object
    Required
  Channel object.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final channel = await aliceSDK.getChannelByDid(
    message.data['memberDid'] as String,
);

if (channel == null) {
    throw Exception('Channel does not exist');
}

await aliceSDK.rejectConnectionRequest(channel);
```

#### leaveChannel

An instance method that allows a member to leave a channel. Depending on type of channel, it applies business logic to groups or individual channels.

Parameters

    groupId
    string
    Required
  The Group ID.

    memberDid
    string
    Required
  The member’s DID.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final groupId = '';
final memberDid = 'did:peer:.....';

await aliceSDK.leaveGroup(groupId, memberDid);
```

#### sendMessage

An instance method that encrypts and signs the message using the sender’s DID, then sends it to recipientDidDocument via DIDComm.

Parameters

    message
    object
    Required
  The DIDComm plain text message.

    senderDid
    string
    Required
  The DID used to send messages.

    recipientDid
    string
    Required
  The DID of recipient.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final bobSDK = await MeetingPlaceCoreSDK.create(
    ...
);

bobSDK.sendMessage(
    message,
    senderDid: senderDid,
    recipientDid: recipientDid,
);
```

#### queueMessage

An instance method that queues the message to be sent via DIDComm.

Parameters

    message
    object
    Required
  The DIDComm plain text message.

    senderDid
    string
    Required
  The DID used to send messages.

    recipientDid
    string
    Required
  The DID of recipient.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final bobSDK = await MeetingPlaceCoreSDK.create(
    ...
);

await bobSDK.queueMessage(
    message,
    senderDid: senderDid,
    recipientDid: recipientDid,
);
```

#### sendGroupMessage

An instance method that encrypts and signs the message using the sender’s DID, then sends it to a group message using a group’s DID as the recipient via DIDComm.

Parameters

    message
    object
    Required
  The DIDComm plain text message.

    senderDid
    string
    Required
  The DID used to send messages.

    recipientDid
    string
    Required
  The DID of recipient.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final bobSDK = await MeetingPlaceCoreSDK.create(
    ...
);

await bobSDK.sendGroupMessage(
    message,
    senderDid: senderDid,
    recipientDid: recipientDid,
);
```

#### sendOutreachInvitation

Sends a targeted invitation to participants of an existing connection offer, inviting them to join a different offer.

Parameters

    outreachConnectionOffer
    ConnectionOffer
    Required
  The outreach connection offer used to send the invitation.

    ConnectionOffer
    ConnectionOffer
    Required
  The connection offer to which the invitee is being invited to connect.

    messageToInclude
    string
    Required
  A custom message to include in the invitation.

    senderInfo
    string
    Required
  Information about the sender to be included in the invitation.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final bobSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final ConnectionOffer outreachOffer = /* existing offer with participants */;

final ConnectionOffer inviteToOffer = /* new offer you want to promote */;

await bobSDK.sendOutreachInvitation(
    outreachConnectionOffer: outreachOffer,
    inviteToConnectionOffer: inviteToOffer,
    messageToInclude: 'Hi! Connect with me on this new offer.',
    senderInfo: 'John',
);
```

#### processControlPlaneEvents

An instance method that fetches latest updates (notifications) from Control Plane API and handles each update event. This may need some time to happen. Therefore the function returns a stream that is going to receive a connection offer for each processed update event.

Parameters

No parameters required.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

// Listen to control plane events stream
aliceSDK.controlPlaneEventsStream.listen((event) {
    print('Event type: ${event.type}');
    if (event.channel != null) {
      print('Channel ID: ${event.channel!.id}');
      print('Channel status: ${event.channel!.status}');
    }
  });

// Process pending control plane events
await aliceSDK.processControlPlaneEvents(
    onDone: () {
      print('All control plane events processed successfully');
    },
);
```

#### disposeDiscoveryEventsStream

An instance method that closes the active discovery events stream.

Parameters

No parameters required.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

await aliceSDK.disposeDiscoveryEventsStream();
```

#### deleteDiscoveryEvents

An instance method that deletes all pending discovery events.

Parameters

No parameters required.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

await aliceSDK.deleteDiscoveryEvents();
```

#### fetchMessages

An instance method that retrieves available messages from the specified mediator instance mediatorDid. By setting deleteOnRetrieve to true, retrieved messages can be automatically deleted. The method takes care of checking message signatures and decrypts the messages if necessary.

Parameters

    did
    string
    Required
  DID used to fetch messages from mediator.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

await aliceSDK.fetchMessages('did:peer:.....');
```

#### subscribeToMediator

An instance method that allows the MeetingPlaceCoreSDK instance to subscribe to incoming messages from the mediator.

Parameters

    did
    string
    Required
  DID used to fetch messages from mediator.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

await aliceSDK.subscribeToMediator('did:peer:.....');
```

#### getConnectionOffer

An instance method that returns the connection offer identified by offerLink from storage.

Parameters

    offerLink
    string
    Required
  The ID of the offer.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final offerLink = '';

await aliceSDK.getConnectionOffer(offerLink);
```

#### markConnectionOfferAsDeleted

An instance method that marks a connection offer as deleted — updates connection offer status to deleted. If the connection offer is already marked as deleted, the delete operation will be skipped.

Parameters

    connectionOffer
    object
    Required
  The ConnectionOffer instance.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final connectionOfferToBeDeleted = '';

await aliceSDK.markConnectionOfferAsDeleted(connectionOfferToBeDeleted);
```

#### deleteConnectionOffer

An instance method that deletes a connection offer from storage.

Parameters

    connectionOffer
    object
    Required
  The ConnectionOffer instance.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final connectionOfferToBeDeleted = '';

await aliceSDK.deleteConnectionOffer(connectionOfferToBeDeleted);
```

#### getGroupByOfferLink

An instance method that returns the group identified by offerLink from storage.

Parameters

    connectionOffer
    object
    Required
  The ConnectionOffer instance.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final offerLink = '';

await aliceSDK.getGroupByOfferLink(offerLink);
```

#### getGroupById

An instance method that returns the group identified by groupId from storage.

Parameters

    groupId
    string
    Required
  The groupID.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final groupId = '';

await aliceSDK.getGroupById(groupId);
```

#### updateGroup

An instance method that updates an existing group in the repository by using repository method updateGroup.

Parameters

    group
    object
    Required
  Specifies the channel entity to update.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final group = Group(
  id: '',
  did: 'did:peer:...',
  offerLink: '',
  members: ['alice', 'bob'],
  created: DateTime.now()
);

await aliceSDK.updateGroup(group);
```

#### listConnectionOffers

An instance method that returns a list of all connection offers from the repository by using repository method listConnectionOffers.

Parameters

No parameters required.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

await aliceSDK.listConnectionOffers();
```

#### getChannelByDid

An instance method that fetches a channel entity from the repository by using repository method getChannelByDid.

Parameters

    did
    string
    Required
  The DID to match the channel either by permanentChannelDid or otherPartyPermanentChannelDid.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

await aliceSDK.getChannelByDid('did:peer:...');
```

#### getChannelByOtherPartyPermanentDid

An instance method that fetches a channel entity from the repository by using repository method findChannelByOtherPartyPermanentChannelDid.

Parameters

    did
    string
    Required
  The DID to match the channel either by permanentChannelDid or otherPartyPermanentChannelDid.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

await aliceSDK.getChannelByOtherPartyPermanentDid('did:peer:...');
```

#### updateChannel

An instance method that updates an existing channel in the repository.

Parameters

    channel
    object
    Required
  Specifies the channel entity to update.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final channel = new Channel({
    ...
});

await aliceSDK.updateChannel(channel);
```

#### getMediatorDidFromUrl

An instance method that fetches the mediator DID from the provided URL.

Parameters

    mediatorEndpoint
    string
    Required
  The mediator endpoint which returns the DID document of the mediator.

Example

```dart
import 'package:meeting_place_core/meeting_place_core.dart';
import 'package:ssi/ssi.dart';
import 'storage/in_memory_storage.dart';

final aliceSDK = await MeetingPlaceCoreSDK.create(
    ...
);

final mediatorEndpoint = 'https://example.com/.well-known/did.json';

await aliceSDK.getMediatorDidFromUrl('');
```