feat: connection termination (#4)

doc/service-agent-api.md

@@ -31,6 +31,7 @@ In addition, it supports a notification mechanism to subscribe to any event the
       - [Menu Selection](#menu-selection)
       - [Invitation](#invitation)
       - [Profile](#profile)
+      - [Terminate Connection](#terminate-connection)
     - [Identity Proof Item types](#identity-proof-item-types)
       - [Verifiable Credential](#verifiable-credential)
         - [Request value](#request-value)
@@ -99,10 +100,10 @@ Currently, the following messages can be submitted and received:
 - Receipts (`receipts`)
 - Invitation (`invitation`)
 - Profile (`profile`)
+- Terminate Connection (`terminate-connection`)
 
 > **TODO**: Messages for:
 >
-> - Open browsing session
 > - System messages in topics
 > - Message signaling (typing)
 
@@ -405,6 +406,17 @@ Sends User Profile to a particular connection. An Agent may have its default pro
 }
 ```
 
+#### Terminate Connection
+
+Terminates a particular connection, notifying the other party through a 'Hangup' message. No further messages will be allowed after this action.
+
+```json
+{
+   ...
+   "type": "terminate-connection",
+}
+```
+
 ### Identity Proof Item types
 
 When a Credential Issuance is requested, the issuer might require the recipient to present certain identity proofing elements.

src/controllers/message/MessageController.ts

@@ -9,6 +9,7 @@ import {
   OutboundMessageContext,
   OutOfBandRepository,
   OutOfBandInvitation,
+  DidExchangeState,
 } from '@credo-ts/core'
 import { QuestionAnswerRepository, ValidResponse } from '@credo-ts/question-answer'
 import { Body, Controller, HttpException, HttpStatus, Logger, Post } from '@nestjs/common'
@@ -27,6 +28,7 @@ import {
   IBaseMessage,
   didcommReceiptFromServiceAgentReceipt,
   IdentityProofResultMessage,
+  TerminateConnectionMessage,
 } from '../../model'
 import { VerifiableCredentialRequestedProofItem } from '../../model/messages/proofs/vc/VerifiableCredentialRequestedProofItem'
 import { AgentService } from '../../services/AgentService'
@@ -78,6 +80,14 @@ export class MessageController {
       const messageType = message.type
       this.logger.debug!(`Message submitted. ${JSON.stringify(message)}`)
 
+      const connection = await agent.connections.findById(message.connectionId)
+
+      if (!connection) throw new Error(`Connection with id ${message.connectionId} not found`)
+
+      if (connection.state === DidExchangeState.Completed && (!connection.did || !connection.theirDid)) {
+        throw new Error(`This connection has been terminated. No further messages are possible`)
+      }
+
       if (messageType === TextMessage.type) {
         const textMsg = JsonTransformer.fromJSON(message, TextMessage)
         const record = await agent.basicMessages.sendMessage(textMsg.connectionId, textMsg.content)
@@ -258,7 +268,6 @@ export class MessageController {
         const msg = JsonTransformer.fromJSON(message, InvitationMessage)
         const { label, imageUrl, did } = msg
 
-        const connection = await agent.connections.getById(msg.connectionId)
         const messageSender = agent.context.dependencyManager.resolve(MessageSender)
 
         if (did) {
@@ -310,8 +319,6 @@ export class MessageController {
         const msg = JsonTransformer.fromJSON(message, ProfileMessage)
         const { displayImageUrl, displayName, displayIconUrl } = msg
 
-        const connection = await agent.connections.getById(msg.connectionId)
-
         await agent.modules.userProfile.sendUserProfile({
           connectionId: connection.id,
           profileData: {
@@ -321,8 +328,15 @@ export class MessageController {
           },
         })
 
+        // FIXME: No message id is returned here
+      } else if (messageType === TerminateConnectionMessage.type) {
+        JsonTransformer.fromJSON(message, TerminateConnectionMessage)
+
+        await agent.connections.hangup({ connectionId: connection.id })
+
         // FIXME: No message id is returned here
       }
+
       this.logger.debug!(`messageId: ${messageId}`)
       return { id: messageId ?? utils.uuid() } // TODO: persistant mapping between AFJ records and Service Agent flows. Support external message id setting
     } catch (error) {

src/events/ConnectionEvents.ts

@@ -1,7 +1,7 @@
 import type { ServerConfig } from '../utils/ServerConfig'
-import type { ConnectionStateChangedEvent } from '@credo-ts/core'
+import type { AgentMessageProcessedEvent, ConnectionStateChangedEvent } from '@credo-ts/core'
 
-import { ConnectionEventTypes, ConnectionRepository } from '@credo-ts/core'
+import { AgentEventTypes, ConnectionEventTypes, ConnectionRepository, HangupMessage } from '@credo-ts/core'
 
 import { ServiceAgent } from '../utils/ServiceAgent'
 
@@ -34,4 +34,21 @@ export const connectionEvents = async (agent: ServiceAgent, config: ServerConfig
       await sendWebhookEvent(config.webhookUrl + '/connection-state-updated', body, config.logger)
     },
   )
+
+  // When a hangup message is received for a given connection, it will be effectively terminated. Service Agent controller
+  // will be notified about this 'termination' status
+  agent.events.on(AgentEventTypes.AgentMessageProcessed, async ({ payload }: AgentMessageProcessedEvent) => {
+    const { message, connection } = payload
+
+    if (message.type === HangupMessage.type.messageTypeUri && connection) {
+      const body = {
+        type: 'connection-state-updated',
+        connectionId: connection.id,
+        invitationId: connection.outOfBandId,
+        state: 'terminated',
+      }
+
+      await sendWebhookEvent(config.webhookUrl + '/connection-state-updated', body, config.logger)
+    }
+  })
 }

src/model/messages/TerminateConnectionMessage.ts

@@ -0,0 +1,19 @@
+import { BaseMessage, BaseMessageOptions } from './BaseMessage'
+
+export interface TerminateConnectionMessageOptions extends BaseMessageOptions {}
+
+export class TerminateConnectionMessage extends BaseMessage {
+  public constructor(options: TerminateConnectionMessageOptions) {
+    super()
+
+    if (options) {
+      this.id = options.id ?? this.generateId()
+      this.threadId = options.threadId
+      this.timestamp = options.timestamp ?? new Date()
+      this.connectionId = options.connectionId
+    }
+  }
+
+  public readonly type = TerminateConnectionMessage.type
+  public static readonly type = 'terminate-connection'
+}

src/model/messages/index.ts

@@ -14,4 +14,5 @@ export * from './MenuDisplayMessage'
 export * from './MenuSelectMessage'
 export * from './ProfileMessage'
 export * from './ReceiptsMessage'
+export * from './TerminateConnectionMessage'
 export * from './TextMessage'