feat(guild-realtime): add websocket gateway with api-key auth and channel rooms

Fabric.Backend.Guild/src/app.module.ts

@@ -8,11 +8,13 @@ import { GuildsModule } from './guilds/guilds.module';
 import { ChannelsModule } from './channels/channels.module';
 import { MessagingModule } from './messaging/messaging.module';
 import { EventsModule } from './events/events.module';
+import { RealtimeModule } from './realtime/realtime.module';
 
 @Module({
   imports: [
     TypeOrmModule.forRoot(buildTypeOrmConfig()),
     EventsModule,
+    RealtimeModule,
     GuildsModule,
     ChannelsModule,
     MessagingModule,

Fabric.Backend.Guild/src/realtime/realtime.gateway.ts

@@ -0,0 +1,72 @@
+import {
+  ConnectedSocket,
+  MessageBody,
+  OnGatewayConnection,
+  OnGatewayDisconnect,
+  SubscribeMessage,
+  WebSocketGateway,
+  WebSocketServer,
+} from '@nestjs/websockets';
+import { Logger } from '@nestjs/common';
+import { Server, Socket } from 'socket.io';
+
+@WebSocketGateway({
+  namespace: '/realtime',
+  cors: {
+    origin: '*',
+  },
+})
+export class RealtimeGateway implements OnGatewayConnection, OnGatewayDisconnect {
+  @WebSocketServer()
+  server!: Server;
+
+  private readonly logger = new Logger(RealtimeGateway.name);
+
+  handleConnection(client: Socket): void {
+    const expected = process.env.FABRIC_API_KEY;
+    if (!expected) {
+      client.disconnect(true);
+      return;
+    }
+
+    const authKey = client.handshake.auth?.apiKey;
+    const headerKey = client.handshake.headers['x-api-key'];
+    const apiKey = typeof authKey === 'string' ? authKey : Array.isArray(headerKey) ? headerKey[0] : headerKey;
+
+    if (apiKey !== expected) {
+      this.logger.warn(`socket rejected: ${client.id}`);
+      client.disconnect(true);
+      return;
+    }
+
+    this.logger.log(`socket connected: ${client.id}`);
+  }
+
+  handleDisconnect(client: Socket): void {
+    this.logger.log(`socket disconnected: ${client.id}`);
+  }
+
+  @SubscribeMessage('join_channel')
+  joinChannel(
+    @ConnectedSocket() client: Socket,
+    @MessageBody() body: { channelId?: string },
+  ): { ok: boolean } {
+    if (!body?.channelId) return { ok: false };
+    client.join(`channel:${body.channelId}`);
+    return { ok: true };
+  }
+
+  @SubscribeMessage('leave_channel')
+  leaveChannel(
+    @ConnectedSocket() client: Socket,
+    @MessageBody() body: { channelId?: string },
+  ): { ok: boolean } {
+    if (!body?.channelId) return { ok: false };
+    client.leave(`channel:${body.channelId}`);
+    return { ok: true };
+  }
+
+  emitChannelEvent(channelId: string, event: string, data: Record<string, unknown>): void {
+    this.server.to(`channel:${channelId}`).emit(event, data);
+  }
+}

Fabric.Backend.Guild/src/realtime/realtime.module.ts

@@ -0,0 +1,9 @@
+import { Global, Module } from '@nestjs/common';
+import { RealtimeGateway } from './realtime.gateway';
+
+@Global()
+@Module({
+  providers: [RealtimeGateway],
+  exports: [RealtimeGateway],
+})
+export class RealtimeModule {}