# WebSocket Subscriptions

Subscribe to real-time order book and price updates using the `client.ws` module.

## Methods

| Method                              | Description                             | Signer |
| ----------------------------------- | --------------------------------------- | ------ |
| `connect(config?)`                  | Open the WebSocket connection           | No     |
| `subscribe(options, callback)`      | Subscribe to a topic                    | No     |
| `unsubscribe(id)`                   | Cancel a subscription                   | No     |
| `subscribeOrders(callback)`         | Convenience: subscribe to order updates | No     |
| `subscribePrices(callback, asset?)` | Convenience: subscribe to price updates | No     |
| `onStateChange(callback)`           | Listen for connection state changes     | No     |
| `getState()`                        | Get current connection state            | No     |
| `disconnect()`                      | Close the connection                    | No     |

## Usage

### Monitor Orders and Prices

```typescript
import { ethers } from 'ethers';
import { ThetanutsClient } from '@thetanuts-finance/thetanuts-client';

const provider = new ethers.JsonRpcProvider('https://mainnet.base.org');
const client = new ThetanutsClient({ chainId: 8453, provider });

// 1. Open the connection
await client.ws.connect();

// 2. Subscribe to order book updates
const unsubOrders = client.ws.subscribeOrders((update) => {
  console.log(`Order ${update.event}:`, update);
});

// 3. Subscribe to ETH price updates
const unsubPrices = client.ws.subscribePrices((update) => {
  console.log(`ETH price: $${update.price}`);
}, 'ETH');

// 4. Monitor connection state
const unsubState = client.ws.onStateChange((state) => {
  console.log(`WebSocket state: ${state}`);
  // state: 'connecting' | 'connected' | 'disconnecting' | 'disconnected'
});

// 5. Clean up when done
unsubOrders();
unsubPrices();
unsubState();
client.ws.disconnect();
```

### Generic subscribe()

Use `subscribe()` directly when you need more control over the subscription topic.

```typescript
import { ethers } from 'ethers';
import { ThetanutsClient } from '@thetanuts-finance/thetanuts-client';

const provider = new ethers.JsonRpcProvider('https://mainnet.base.org');
const client = new ThetanutsClient({ chainId: 8453, provider });

await client.ws.connect();

const subscriptionId = client.ws.subscribe({ type: 'orders' }, (update) => {
  console.log('Order update:', update);
});

// Later, cancel using the returned subscription ID
client.ws.unsubscribe(subscriptionId);
```

### Reconnection Behavior

The WebSocket module auto-reconnects by default (up to 10 attempts). You can observe reconnections via `onStateChange`:

```typescript
client.ws.onStateChange((state) => {
  if (state === 'disconnected') {
    console.log('Connection lost — SDK will auto-reconnect...');
  }
  if (state === 'connected') {
    console.log('Reconnected successfully');
  }
});
```

To manually reconnect after complete disconnection:

```typescript
await client.ws.connect();
```

### Checking Connection State

```typescript
const state = client.ws.getState();
// 'connecting' | 'connected' | 'disconnecting' | 'disconnected'

if (state !== 'connected') {
  await client.ws.connect();
}
```

## Configuration

Pass a custom WebSocket URL at client initialization if you need to override the default endpoint:

```typescript
import { ThetanutsClient } from '@thetanuts-finance/thetanuts-client';

const client = new ThetanutsClient({
  chainId: 8453,
  provider,
  wsUrl: 'wss://your-custom-ws-endpoint',  // Optional override
});
```

## See Also

* [Events](/sdk/guides/events.md) — query historical blockchain events when real-time data is not needed
* [Production Checklist](/sdk/guides/production-checklist.md) — WebSocket reconnection configuration
* [Error Handling](/sdk/guides/error-handling.md) — `WEBSOCKET_ERROR` error code


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.thetanuts.finance/sdk/guides/websocket.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.