Send Notifications from your service

Send user-facing notifications by publishing a NotificationEvent to the platform pub/sub.
No direct call to the Notification Service is needed.

1) Dependencies (common + optional SDK)

Common library (events & enums)

  • Package imports you’ll use:

    • de.unistuttgart.iste.meitrex.common.event.NotificationEvent

    • de.unistuttgart.iste.meitrex.common.event.ServerSource

    • de.unistuttgart.iste.meitrex.common.dapr.TopicPublisher

  • Dependency (example coordinates; use your internal artifact):

    Gradle: implementation(“de.unistuttgart.iste.meitrex:meitrex-common:1.4.9”)

(Optional) Dapr Java SDK (publish via SDK instead of raw HTTP)

  • io.dapr:dapr-sdk:1.9.0

2) Payload shape: NotificationEvent

Either provide userIds (direct recipients) or a courseId (broadcast). When courseId is included, course title will be added automatically. If the settings service is down, delivery fails open (users still get the notification but won’t be queried by frontend).

{
  "userIds": ["<uuid>", "..."],   // XOR courseId
  "courseId": "<uuid>",           // XOR userIds
  "serverSource": "MEDIA",        // use ServerSource enum
  "title": "New material uploaded",
  "message": "Lecture 02 slides are available",
  "link": "/courses/<courseId>/media/<contentId>?selectedDocument=<mediaId>"
}

Notes:

  • Use your real front-end path in link (document/video/quiz/flashcards, etc.).

  • If both userIds and courseId are empty → the event is ignored.

3) Publish

Java + Dapr SDK

import de.unistuttgart.iste.meitrex.common.dapr.TopicPublisher;
import de.unistuttgart.iste.meitrex.common.event.ServerSource;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Service;

import java.util.UUID;

@Service
@RequiredArgsConstructor
public class MyDomainService {

  private final TopicPublisher topicPublisher;

  public void sendNotification(UUID courseId) {
    String link = "/courses/" + courseId;
    topicPublisher.notificationEvent(
        courseId,                 // course broadcast
        null,                     // OR: a list of userIds
        ServerSource.MEDIA,       // choose the enum matching your service
        link,
        "New material uploaded",
        "Lecture 02 slides are available"
    );
  }
}

Replace messagebus and notifications with your actual pubsub component and topic.

4) Quick verification

GraphQL (via gateway):

query {
  currentUserInfo {
    id
    notificationUnreadCount
    notifications { id title read }
  }
}

If everything is wired, unread count increases and the new item appears.

Cheatsheet

  • Choose one: userIds or courseId.

  • Use ServerSource enum (e.g., MEDIA, CONTENT, ASSIGNMENT, …).

  • link must point to a valid front-end route.

  • Pub/sub names and ports come from your Dapr setup (DAPR_HTTP_PORT, component name, topic name).