Socket.IO Component

Real-time, bidirectional, event-based communication using Socket.IO.

Quick Reference

Component	Purpose
SocketIOComponent	Sets up Socket.IO server and bindings
SocketIOServerHelper	Encapsulates Socket.IO server instance
Redis Adapter	Enables horizontal scaling with Redis
Redis Emitter	Emit events from other processes/services

Required Bindings

Binding Key	Type	Purpose
SERVER_OPTIONS	ISocketIOOptions	Socket.IO server configuration (optional)
REDIS_CONNECTION	DefaultRedisHelper	Redis instance for scaling
AUTHENTICATE_HANDLER	Function	Authenticate socket connections
CLIENT_CONNECTED_HANDLER	Function	Handle successful connections (optional)

Use Cases

• Live notifications
• Real-time chat
• Collaborative editing
• Live data streams

Architecture Components

• SocketIOComponent: Sets up Socket.IO server, binds SocketIOServerHelper to DI
• SocketIOServerHelper: Wraps Socket.IO server, provides interaction methods
• @socket.io/redis-adapter: Scales Socket.IO with Redis
• @socket.io/redis-emitter: Emits events from external processes
• Integration: Works with HTTP server and authentication system

Implementation Details

Tech Stack

• Socket.IO
• @socket.io/redis-adapter
• @socket.io/redis-emitter
• ioredis (if using Redis)

Configuration

To use the Socket.IO component, you need to provide a few things in your application's DI container:

• SocketIOBindingKeys.SERVER_OPTIONS: (Optional) Custom options for the Socket.IO server.
• SocketIOBindingKeys.REDIS_CONNECTION: An instance of DefaultRedisHelper (or a compatible class) for the Redis adapter.
• SocketIOBindingKeys.AUTHENTICATE_HANDLER: A function to handle the authentication of new socket connections.
• SocketIOBindingKeys.CLIENT_CONNECTED_HANDLER: (Optional) A function to be called when a client is successfully connected and authenticated.

Code Samples

1. Setting up the Socket.IO Component

In your src/application.ts:

import {
  SocketIOComponent,
  SocketIOBindingKeys,
  RedisHelper, // Your Redis helper
  BaseApplication,
  ValueOrPromise,
  IHandshake,
} from '@venizia/ignis';

// ...

export class Application extends BaseApplication {
  // ...

  preConfigure(): ValueOrPromise<void> {
    // ...

    // 1. Bind Redis connection
    const redis = new RedisHelper({
      name: 'redis',
      host: 'localhost',
      port: 6379,
      password: 'password',
    });
    this.bind({ key: SocketIOBindingKeys.REDIS_CONNECTION }).toValue(redis);

    // 2. Bind authentication handler
    const authenticateFn = async (handshake: IHandshake) => {
      const { token } = handshake.auth;
      // Your custom authentication logic here
      // e.g., verify a JWT
      return !!token;
    };
    this.bind({ key: SocketIOBindingKeys.AUTHENTICATE_HANDLER }).toValue(authenticateFn);

    // 3. Register the component
    this.component(SocketIOComponent);
  }

  // ...
}

2. Emitting Events

You can get the SocketIOServerHelper instance from the container and use it to emit events.

import { SocketIOServerHelper, SocketIOBindingKeys, inject } from '@venizia/ignis';

// ... in a service or controller

  @inject({ key: SocketIOBindingKeys.SOCKET_IO_INSTANCE })
  private io: SocketIOServerHelper;

  sendNotification(userId: string, message: string) {
    this.io.send({
      destination: userId, // Room or socket ID
      payload: {
        topic: 'notification',
        data: { message },
      },
    });
  }