Skip to main content

ActivitiesHandlerMixin

Watch for ActivityPub activities matching certain patterns and easily handle side effects.

Usage​

const { ActivitiesHandlerMixin, ACTIVITY_TYPES, OBJECT_TYPES, matchActivity } = require('@semapps/activitypub');

module.exports = {
  mixins: [ActivitiesHandlerMixin],
  activities: {
    joinEvent: {
      match: {
        type: ACTIVITY_TYPES.JOIN,
        object: {
          type: OBJECT_TYPES.EVENT
        }
      },
      async onEmit(ctx, activity, emitterUri) {
        // Handle side effects on emit
      },
      async onReceive(ctx, activity, recipientUri) {
        // Handle side effects on receive
      }
    },
    myAnnounceActivity: {
      async match(activity, fetcher) {
        if (activity.actor !== 'http://localhost:3000/myself') {
          return { match: false, dereferenceActivity: activity };
        } else {
          return await matchActivity({ type: ACTIVITY_TYPES.ANNOUNCE }, activity, fetcher);
        }
      },
      async onEmit(ctx, activity, emitterUri) {
        // Handle side effects on emit
      },
      async onReceive(ctx, activity, recipientUri) {
        // Handle side effects on receive
      }
    }
  }
};

The activity object passed to the onEmit and onReceive functions is dereferenced according to the pattern. In the above case, the Event object will be dereferenced, even if on the original activity, it included only an URI. If you use a function for the match property, the value you return will passed to the onEmit and onReceive functions.