# AbstractWsAdapter

**Kind:** Class

**Source:** [`packages/websockets/adapters/ws-adapter.ts`](https://github.com/nestjs/nest/blob/master/packages/websockets/adapters/ws-adapter.ts#L13)

**Part of:** [Websockets](subsystem-packages-websockets)

`AbstractWsAdapter` is the base class for WebSocket transport adapters in NestJS. It provides shared lifecycle behavior for client connection/disconnection events and server cleanup, while concrete adapters implement server creation and message-handler binding for a specific WebSocket library.

**Implements:** `WebSocketAdapter`

## Methods

| Method | Signature | Returns |
|---|---|---|
| `bindClientConnect` | `bindClientConnect(server: TServer, callback: Function)` | `void` |
| `bindClientDisconnect` | `bindClientDisconnect(client: TClient, callback: Function)` | `void` |
| `close` | `close(server: TServer)` | `void` |
| `dispose` | `dispose()` | `void` |
| `create` | `create(port: number, options: TOptions)` | `TServer` |
| `bindMessageHandlers` | `bindMessageHandlers(client: TClient, handlers: WsMessageHandler[], transform: (data: any) => Observable<any>)` | `void` |

## Properties

| Property | Type |
|---|---|
| `httpServer` | `any` |

## Diagram

```mermaid
graph LR
  App[Nest Application] --> Adapter[AbstractWsAdapter]
  Adapter --> Create[create()]
  Adapter --> Connect[bindClientConnect()]
  Adapter --> Disconnect[bindClientDisconnect()]
  Adapter --> Messages[bindMessageHandlers()]
  Adapter --> Close[close() / dispose()]
  Create --> Server[WebSocket Server]
  Server --> Client[WebSocket Client]
  Client --> Messages
```

## Usage

```ts
import { AbstractWsAdapter } from '@nestjs/websockets';

class CustomWsAdapter extends AbstractWsAdapter<MyServer, MyClient> {
  create(port: number): MyServer {
    return createMyWebSocketServer(port);
  }

  bindMessageHandlers(client: MyClient, handlers, transform) {
    client.on('message', async rawMessage => {
      const message = JSON.parse(rawMessage.toString());

      for (const handler of handlers) {
        if (handler.message === message.event) {
          const response = await transform(
            handler.callback(message.data, client),
          );

          client.send(JSON.stringify(response));
        }
      }
    });
  }
}

// main.ts
async function bootstrap() {
  const app = await NestFactory.create(AppModule);

  app.useWebSocketAdapter(new CustomWsAdapter(app));
  await app.listen(3000);
}
```

## AI Coding Instructions

- Extend `AbstractWsAdapter` rather than instantiating it directly; implement `create()` and `bindMessageHandlers()` for the chosen WebSocket library.
- Use `bindClientConnect()` and `bindClientDisconnect()` to attach lifecycle callbacks instead of duplicating connection event wiring.
- Ensure incoming messages are parsed and routed to the matching Nest gateway handler in `bindMessageHandlers()`.
- Always support adapter cleanup through `close()` and `dispose()`, especially when the underlying server keeps open client connections.
- Register the concrete adapter with `app.useWebSocketAdapter()` during application bootstrap.

## Used by

2 references from 2 files. Each is a place in this repository where the symbol is actually used — go read one rather than trusting an example.

### Imported by (2)

- `IoAdapter` — `packages/platform-socket.io/adapters/io-adapter.ts`:14
- `WsAdapter` — `packages/platform-ws/adapters/ws-adapter.ts`:39