nestjs-slack-example

Example app for nestjs-slack-listener

Scenario

This app is a simple example of how to use nestjs-slack-listener to build a slack app. It sends a welcome message with instructions to a new user. The user can press the 'Done!' button to complete the onboarding process.

Subscribe Slack Events and Interactivity

The controller is decorated with @SlackEventListener() and @SlackInteractivityListener to subscribe the events and interactivity.

@Controller('on-boarding')
@SlackEventListener()
@SlackInteractivityListener()
export class OnBoardingController {
  ...
}

When the user joins to the team, the method decorated with @SlackEventHandler('team_join') is called.

@SlackEventHandler('team_join')
async onTeamJoin({
  event: { user: member },
}: IncomingSlackEvent<TeamJoinEvent>) {
  return this.onboardingService.startOnBoarding({ member });
}

When the user presses the 'Done!' button, the method decorated with @SlackInteractivityHandler(ACTION_ID.COMPLETE_QUEST) is called.

@SlackInteractivityHandler(ACTION_ID.COMPLETE_QUEST)
async completeQuest({
  user: { id: userSlackId },
  actions: [{ value: questUserId }],
}: IncomingSlackInteractivity) {
  if (userSlackId !== questUserId) {
    throw new ForbiddenException();
  }
  return this.onboardingService.completeQuest({
    userSlackId,
  });
}

Send a message to channel with the Slack Client

The SlackClient is injected to the service class, enabling it to send a message to the channel.

@Injectable()
export class OnBoardingService {
  constructor(
    private readonly userRepository: UserRepository,
    @InjectSlackClient()
    private readonly slack: SlackClient,
  ) {}
  ...
}

Include a action block in the message so the user can call the controller method decorated with @SlackInteractivityHandler(ACTION_ID.COMPLETE_QUEST).

        {
          type: 'actions',
          elements: [
            {
              type: 'button',
              value: `${user.id}`,
              action_id: ACTION_ID.COMPLETE_QUEST,
              text: { type: 'plain_text', text: ':white_check_mark: Done!' },
            },
          ],
        },

The SlackClient is identical to the official Slack Web API Client

await this.slack.chat.postMessage(this.buildIntroBlock(user));