feat: bootstrap from Fabric monorepo

src/realtime/realtime.gateway.ts

@@ -0,0 +1,129 @@
+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);
+  private readonly onlineUsers = new Set<string>();
+
+  private userIdFromClient(client: Socket): string {
+    const authUser = client.handshake.auth?.userId;
+    const headerUser = client.handshake.headers['x-user-id'];
+    const userId = typeof authUser === 'string' ? authUser : Array.isArray(headerUser) ? headerUser[0] : headerUser;
+    return userId && typeof userId === 'string' && userId.trim() !== '' ? userId : `anon:${client.id}`;
+  }
+
+  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}`);
+
+    const userId = this.userIdFromClient(client);
+    client.data.userId = userId;
+    this.onlineUsers.add(userId);
+    this.server.emit('presence.online', {
+      userId,
+      onlineCount: this.onlineUsers.size,
+      occurredAt: new Date().toISOString(),
+    });
+  }
+
+  handleDisconnect(client: Socket): void {
+    this.logger.log(`socket disconnected: ${client.id}`);
+
+    const userId = typeof client.data.userId === 'string' ? client.data.userId : `anon:${client.id}`;
+    this.onlineUsers.delete(userId);
+    this.server.emit('presence.offline', {
+      userId,
+      onlineCount: this.onlineUsers.size,
+      occurredAt: new Date().toISOString(),
+    });
+  }
+
+  @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 };
+  }
+
+  @SubscribeMessage('typing.start')
+  typingStart(
+    @ConnectedSocket() client: Socket,
+    @MessageBody() body: { channelId?: string },
+  ): { ok: boolean } {
+    if (!body?.channelId) return { ok: false };
+
+    const userId = typeof client.data.userId === 'string' ? client.data.userId : `anon:${client.id}`;
+    this.server.to(`channel:${body.channelId}`).emit('typing.start', {
+      channelId: body.channelId,
+      userId,
+      occurredAt: new Date().toISOString(),
+    });
+    return { ok: true };
+  }
+
+  @SubscribeMessage('typing.stop')
+  typingStop(
+    @ConnectedSocket() client: Socket,
+    @MessageBody() body: { channelId?: string },
+  ): { ok: boolean } {
+    if (!body?.channelId) return { ok: false };
+
+    const userId = typeof client.data.userId === 'string' ? client.data.userId : `anon:${client.id}`;
+    this.server.to(`channel:${body.channelId}`).emit('typing.stop', {
+      channelId: body.channelId,
+      userId,
+      occurredAt: new Date().toISOString(),
+    });
+    return { ok: true };
+  }
+
+  emitChannelEvent(channelId: string, event: string, data: Record<string, unknown>): void {
+    this.server.to(`channel:${channelId}`).emit(event, data);
+  }
+}

src/realtime/realtime.module.ts

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