Refactor matching logic (#83)

Author: Jajared

backend/gateway-service/src/modules/match/match.controller.ts

@@ -12,7 +12,7 @@ import { Inject } from '@nestjs/common';
 import { firstValueFrom } from 'rxjs';
 import { RedisService } from './redis.service';
 import { MatchRequestDto } from './dto';
-import { MATCH_SUCCESS, MATCH_TIMEOUT } from './match.event';
+import { MATCH_FOUND, MATCH_CANCELLED, MATCH_CONFIRMED, MATCH_TIMEOUT, MATCH_REQUESTED } from './match.event';
 
 @WebSocketGateway({ namespace: '/match' })
 export class MatchGateway implements OnGatewayInit {
@@ -48,27 +48,39 @@ export class MatchGateway implements OnGatewayInit {
 
     // Send the match request to the microservice
     try {
-      await firstValueFrom(this.matchingClient.send('match.request', matchPayload));
+      firstValueFrom(this.matchingClient.send('match.request', matchPayload))
+        .then(() => console.log(`Match requested for user ${payload.userId}`))
+        .catch((error) => console.error(`Error requesting match for user ${payload.userId}: ${error.message}`));
+      this.server.to(client.id).emit(MATCH_REQUESTED, {
+        message: `Match request sent to the matching service.`,
+      });
     } catch (error) {
       client.emit('matchError', `Error requesting match: ${error.message}`);
       return;
     }
   }
 
+  @SubscribeMessage('matchCancel')
+  async handleCancelMatch(@ConnectedSocket() client: Socket, @MessageBody() payload: { userId: string }) {
+    firstValueFrom(this.matchingClient.send('match.cancel', { userId: payload.userId }))
+      .then(() => console.log(`Match canceled for user ${payload.userId}`))
+      .catch((error) => console.error(`Error canceling match for user ${payload.userId}: ${error.message}`));
+    this.server.to(client.id).emit(MATCH_CANCELLED, {
+      message: `You have been cancelled from the match.`,
+    });
+  }
+
   // Notify both matched users via WebSocket
   notifyUsersWithMatch(matchedUsers: string[]) {
     const [user1, user2] = matchedUsers;
     const user1SocketId = this.getUserSocketId(user1);
     const user2SocketId = this.getUserSocketId(user2);
-    if (user1SocketId) {
-      this.server.to(user1SocketId).emit(MATCH_SUCCESS, {
+    if (user1SocketId && user2SocketId) {
+      this.server.to(user1SocketId).emit(MATCH_FOUND, {
         message: `You have been matched with user ${user2}`,
         matchedUserId: user2,
       });
-    }
-
-    if (user2SocketId) {
-      this.server.to(user2SocketId).emit(MATCH_SUCCESS, {
+      this.server.to(user2SocketId).emit(MATCH_FOUND, {
         message: `You have been matched with user ${user1}`,
         matchedUserId: user1,
       });
@@ -95,13 +107,17 @@ export class MatchGateway implements OnGatewayInit {
     }
   }
 
-  handleDisconnect(@ConnectedSocket() client: Socket) {
+  async handleDisconnect(@ConnectedSocket() client: Socket) {
     const userId = [...this.userSockets.entries()].find(
       ([, socketId]) => socketId === client.id,
     )?.[0];
 
     if (userId) {
       this.userSockets.delete(userId);
+      // Remove user from Redis pool
+      firstValueFrom(this.matchingClient.send('match.cancel', { userId }))
+        .then(() => console.log(`Match canceled for user ${userId}`))
+        .catch((error) => console.error(`Error canceling match for user ${userId}: ${error.message}`));
       console.log(`User ${userId} disconnected`);
     }
   }

backend/gateway-service/src/modules/match/match.event.ts

@@ -1,3 +1,5 @@
-export const MATCH_TIMEOUT = 'matchTimeout';
-export const MATCH_SUCCESS = 'matchSuccess';
-
+export const MATCH_FOUND = 'matchFound'; // Emitted when a match is found
+export const MATCH_REQUESTED = 'matchRequested'; // Emitted when a user requests a match
+export const MATCH_CANCELLED = 'matchCancelled'; // Emitted when a match is cancelled
+export const MATCH_CONFIRMED = 'matchConfirmed'; // Emitted when a match is confirmed
+export const MATCH_TIMEOUT = 'matchTimeout'; // Emitted after 5 minutes of inactivity

backend/matching-service/src/app.controller.ts

@@ -11,4 +11,9 @@ export class AppController {
   async handleMatchRequest(@Payload() data: MatchRequestDto) {
     await this.appService.requestMatch(data); 
   }
+
+  @MessagePattern('match.cancel')
+  async handleMatchCancel(@Payload() data: { userId: string }) {
+    await this.appService.cancelMatch(data.userId);
+  }
 }

backend/matching-service/src/app.service.ts

@@ -1,5 +1,4 @@
 import { Injectable } from '@nestjs/common';
-import Redis from 'ioredis';
 import { MatchRequestDto } from './dto/match-request.dto';
 import { RedisService } from './redis.service';
 
@@ -11,6 +10,11 @@ export class AppService {
   async requestMatch(data: MatchRequestDto): Promise<void> {
     await this.redisService.addUserToPool(data);
   }
+
+  // Remove user from the Redis pool
+  async cancelMatch(userId: string): Promise<void> {
+    await this.redisService.removeUsersFromPool([userId]);
+  }
 }
 
 

backend/matching-service/src/match-worker.service.ts

@@ -12,7 +12,7 @@ export class MatchWorkerService {
     setInterval(async () => {
       const users = await this.redisService.getUsersFromPool();
       const currentTime = Date.now();
-      const timeout = 29000; // Slightly less than 30 seconds to account for processing time
+      const timeout = 300000; // 5 minutes to remove any zombie users
       console.log('Polling', users);
       // Filter out users who have timed out
       const activeUsers = users.filter(user => currentTime - user.timestamp < timeout);
@@ -33,7 +33,7 @@ export class MatchWorkerService {
         // Remove the matched users from the Redis pool
         await this.redisService.removeUsersFromPool([bestMatch.user1.userId, bestMatch.user2.userId]);
       }
-    }, 20000);
+    }, 5000);
   }
 
   // Ranking logic for matches