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🗄️ DatabasesVercel

Subscriptions/real-time API support

Freshabout 20 hours ago
Mar 14, 20260 views
Confidence Score95%
95%

Problem

Unfortunately at the current point of time Prisma 2 doesn't yet support subscriptions (real-time API features). Prisma 1 followed a different architecture which provided support for subscriptions. We might be planning to bring back real-time/subscriptions functionality in the future based on a standalone "events engine" (which will use CDC under the hood). This issue tracks the progress for this feature. Please feel free to share your specific requirements and wishes for this feature. 🙏

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2 Fixes

Canonical Fix
Unverified Fix
New Fix – Awaiting Verification

Implement Event Engine for Real-Time Subscriptions in Prisma

Medium Risk

Prisma 2 currently lacks built-in support for real-time subscriptions due to its architecture, which differs from Prisma 1. The absence of an events engine means that changes in the database cannot be pushed to clients in real-time, limiting the application's interactivity and responsiveness.

Awaiting Verification

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  1. 1

    Design the Events Engine Architecture

    Define the architecture for the standalone events engine that will handle change data capture (CDC) and manage real-time subscriptions. This should include the components responsible for listening to database changes and broadcasting updates to clients.

    javascript
    const { EventEmitter } = require('events');

class EventsEngine extends EventEmitter {
  constructor() {
    super();
    // Initialize CDC listener
  }

  listenToChanges() {
    // Logic to listen to database changes
  }

  broadcastUpdate(data) {
    this.emit('update', data);
  }
}
  2. 2

    Integrate CDC with PostgreSQL

    Utilize PostgreSQL's logical replication or triggers to capture changes in the database. This will allow the events engine to receive updates whenever data is modified, ensuring that clients can receive real-time notifications.

    sql
    CREATE TRIGGER notify_changes
AFTER INSERT OR UPDATE OR DELETE ON your_table_name
FOR EACH ROW
EXECUTE FUNCTION notify_event();
  3. 3

    Implement WebSocket Server for Client Communication

    Set up a WebSocket server that will allow clients to subscribe to specific events. When the events engine broadcasts an update, the WebSocket server will push this update to all connected clients.

    javascript
    const WebSocket = require('ws');

const wss = new WebSocket.Server({ port: 8080 });

wss.on('connection', function connection(ws) {
  ws.on('message', function incoming(message) {
    // Handle client subscription
  });
});
  4. 4

    Create Client-Side Subscription Logic

    Develop the client-side logic to connect to the WebSocket server and handle incoming updates. This will allow the application to react to changes in real-time, providing a seamless user experience.

    javascript
    const socket = new WebSocket('ws://localhost:8080');

socket.onmessage = function(event) {
  const data = JSON.parse(event.data);
  // Update UI with new data
};
  5. 5

    Test and Validate the Real-Time Functionality

    Conduct thorough testing to ensure that the events engine correctly captures changes and that the WebSocket server reliably pushes updates to clients. Validate that all scenarios (insert, update, delete) are handled appropriately.

    javascript
    // Test cases to validate real-time updates
expect(data).toEqual(expectedData);

Validation

Confirm the fix by testing the application to ensure that real-time updates are received by clients when changes occur in the database. Monitor the WebSocket connections and verify that all expected events are emitted and handled correctly.

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1 low-confidence fix
Unverified Fix
New Fix – Awaiting Verification

Implement Event-Driven Architecture for Real-Time Subscriptions

Medium Risk

Prisma 2 does not currently support real-time subscriptions due to its architectural design, which differs from Prisma 1. The absence of an events engine limits the ability to push updates to clients in real-time, as there is no mechanism to listen for changes in the database.

Awaiting Verification

Be the first to verify this fix

  1. 1

    Design Event-Driven Architecture

    Outline the architecture for an event-driven system that can handle real-time subscriptions. This should include defining the event sources, event types, and how they will be processed.

    N/A
    N/A
  2. 2

    Integrate Change Data Capture (CDC)

    Implement a Change Data Capture mechanism that listens to database changes. This can be achieved using tools like Debezium or custom triggers in PostgreSQL to capture changes and publish events to a message broker.

    sql
    CREATE TRIGGER my_trigger AFTER INSERT OR UPDATE OR DELETE ON my_table FOR EACH ROW EXECUTE FUNCTION notify_event();
  3. 3

    Set Up a Message Broker

    Choose and set up a message broker (e.g., Kafka, RabbitMQ) to handle the events generated by the CDC mechanism. This broker will facilitate communication between the database and the clients.

    N/A
    N/A
  4. 4

    Develop Subscription API Endpoints

    Create API endpoints that allow clients to subscribe to specific events. This could be implemented using WebSockets or Server-Sent Events (SSE) to push updates to clients in real-time.

    javascript
    const WebSocket = require('ws');
const wss = new WebSocket.Server({ port: 8080 });
wss.on('connection', function connection(ws) {
  // Logic to send events to the client
});
  5. 5

    Test Real-Time Functionality

    Conduct thorough testing to ensure that the real-time subscription functionality works as intended. This includes testing the event flow from the database to the client and ensuring that updates are received in real-time.

    N/A
    N/A

Validation

Confirm that clients receive real-time updates when changes occur in the database. This can be tested by making changes to the database and observing if the subscribed clients receive the corresponding events.

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Environment

Submitted by

AC

Alex Chen

2450 rep

Tags

prismaormpostgresqlkind/featuretopic:-realtimetopic:-subscription