Yaya ake gina abubuwan da suka fadi-fadi tare da WebSocket gateways?

Question

Accepted Answer

NestJS yana goyan bayan **abubuwan sadarwa da suka fadi-fadi, da juna-jutayya** ta hanyar **WebSocket gateways** — azuzuwan da aka yi alama da `@WebSocketGateway()` da suke sarrafa sadarwar WebSocket da sakunan (yawanci ta Socket.IO). Suna ba da dama ga abubuwan kamar cewa, sanarwa da suka fadi-fadi, da dasibodi masu raɗi, suna amfani da tsarin NestJS ɗaya (DI, decorators).

## Kaida da takardu

```ts
import { WebSocketGateway, SubscribeMessage, MessageBody, WebSocketServer } from "@nestjs/websockets";
import { Server } from "socket.io";

@WebSocketGateway({ cors: true })
export class ChatGateway {
  @WebSocketServer()
  server: Server;                        // the Socket.IO server instance

// handle a 'message' event from a client
  @SubscribeMessage("message")
  handleMessage(@MessageBody() data: { text: string }) {
    // BROADCAST to all connected clients
    this.server.emit("message", data);   // everyone receives the message
  }
}
```

Gateway yana amfani da `@SubscribeMessage("event")` don sarrafa buğitattun abubuwan (kama da `@Post` ga HTTP) kuma aka shigar da `server` don **aika** abubuwan baje zuwa ga abokan ciniki — `server.emit` yana yada ga kowa.

## Natasuwan sakewa na haɗi

```ts
export class ChatGateway implements OnGatewayConnection, OnGatewayDisconnect {
  handleConnection(client: Socket) {
    console.log(`Client connected: ${client.id}`);   // a user joined
  }
  handleDisconnect(client: Socket) {
    console.log(`Client disconnected: ${client.id}`); // a user left — clean up
  }
}
```

Gateways na iya karɓa abokan ciniki da suke haɗi da wajen wajen acikin suna fadi — m ba da mahimmanci don gida-gidan kasua da tsafin da tsafin.

## Sa jiye takamaiman abokan ciniki da ɗakuna

```ts
@SubscribeMessage("joinRoom")
handleJoin(@ConnectedSocket() client: Socket, @MessageBody() room: string) {
  client.join(room);                              // add the client to a room
}

@SubscribeMessage("roomMessage")
sendToRoom(@MessageBody() data: { room: string; text: string }) {
  this.server.to(data.room).emit("message", data.text);   // emit only to that room
  // client.emit(...) → just that client; server.emit(...) → everyone
}
```

**Ɗakuna** sun tara abokan ciniki (misali cewa jerin cewa, waɗanda ke aiki da sakinan), yana ba da damar yada zuwa takamaiman wasu maimakon kowa — mahimmanci ga abubuwan da suka fadi-fadi da suke sarrafa.

## Gateways na sake amiyo abubuwan NestJS

```text
Gateways are providers → they support dependency injection (inject services),
and can use guards, pipes, interceptors, and filters — just like HTTP controllers.
→ The same structure/patterns apply to real-time as to REST.
```

## Yadawa WebSockets

```text
⚠️ WebSocket connections are STATEFUL and live on ONE server instance.
To scale across multiple instances, use a Redis adapter (socket.io-redis) so
broadcasts/rooms work across all instances. (Like sessions, don't keep state in
one process's memory when scaling horizontally.)
```

## Me ya sa inacike

WebSocket gateways shine yadda NestJS ke goyan bayan **abubuwan da suka fadi-fadi, da juna-jutayya** — cewa, sanarwa da suka fadi-fadi, kasua, gyare-gyaren haɗi, dasibodi masu raɗi, hulɗan marasa dadi — waɗanda tsarin neman-amsa na REST ba za su iya bayar da (sakin da zai iya tureshi abokan ciniki, ba kawai amsa ga buğitattun kada). Fahimtarwa tana da mahimmanci sanin babbar-babbar don gina programoyin da suka yin aiki da jiya-jiya. Karfin babbar shine cewa gateways sun yi daidai da tsarin NestJS da aka saba: sun kasua masu goyan bayan **dependency injection** kuma na iya amfani da **guards, pipes, interceptors, kuma filters** kamar HTTP controllers, tunda tsarin ɗaya kuma yin izini na kodda yana amfani da abubuwan da suka fadi-fadi kamar da REST. Sanin yadda za a sarrafa abubuwan (`@SubscribeMessage`), yada zuwa abokan ciniki (`server.emit`), amfani da **ɗakuna** don sarrafa yada zuwa abubuwan da suka dace (jerin cewa, waɗanda ke aiki da sakinan), kuma sarrafa sakewa na haɗi (kasua, tsafin) yana kaita abubuwan da suka fadi-fadi. Mahimmanci ne gida-gida shine **abin la'akari na yadawa**: sadarwar WebSocket ita sun haɗi da wani sakamakon aziye kuma sun shiga takamaiman saiti, don haka yadawa ta gidaje yana buƙacin **Redis adapter** don haɗa broadcasts/ɗakuna juna da juna aziye (abin san lura mai sudji — kamar saida, abubuwan da suka fadi-fadi ba za su kusu jiya cikin alaƒa gida idan aida da yawa). Wannan ita ce mahimmanci, karfin mahimmanci don gina abubuwan da suka fadi-fadi, da raɗi ɗa waɗanda modern masu amfani ke buƙa, kuma tsarin NestJS wanda ya kusa yana ba da dama tare da sake amfani da tsarin framework ɗin.