# SocketService

> Documentation for Redweb 0.16.1. Install that exact version when following these examples.

Route-scoped background worker. Used by `SocketRoute` to run ticks or lifecycle hooks tied to a specific route.

## Explain it like I’m five

A SocketService is a helper that clocks in when its route starts and clocks out when the route stops, such as presence tracking or a periodic snapshot publisher.

## When should I use it?

Use it for route-scoped background behavior that needs explicit startup, shutdown, and access to the owning route.

## Follow the example

This API pattern illustrates the named surface; it may require application-owned classes, credentials, or assets. Start from a complete recipe for a runnable application.

```js
import { SocketService } from 'redweb'

class ClockService extends SocketService {
  constructor() { super('clock', 1000) }
  onTick() {
    this.route.clients.forEach((socket) => socket.sendJson({ type: 'time', now: Date.now() }))
  }
}
```

1. SocketRoute constructs and initializes the service through onInit(route).
2. The optional tick interval invokes onTick; simple SocketService ticks do not await earlier asynchronous ticks.
3. onShutdown releases the interval; overrides must also release their application resources and call the base cleanup.

## Methods and members

### constructor(name, tickRateMs = null)

Stores a service id and optional tick interval; the interval is activated in onInit if onTick exists.

### onInit(route)

Called once by SocketRoute, sets `this.route` and, if a tick interval was supplied, schedules recurring onTick execution.

### onTick()

Optional; implement to run on the configured interval.

### onShutdown()

Clears the tick interval; extend for cleanup hooks.

## What should I watch for?

Use onInit/onShutdown, not start/stop hooks. Use FixedStepService for non-overlapping async ticks and bounded catch-up; plain SocketService does not provide those guarantees.