Server-Sent Events

GoNest provides built-in SSE support for real-time server-to-client streaming.

SSE Endpoint

func (c *Controller) Register(r gonest.Router) {
    r.Get("/events", gonest.SSE(func(stream *gonest.SSEStream) {
        ticker := time.NewTicker(time.Second)
        defer ticker.Stop()

        for i := 0; i < 100; i++ {
            <-ticker.C
            stream.Send(gonest.SSEEvent{
                ID:    fmt.Sprintf("%d", i),
                Event: "update",
                Data:  map[string]any{"count": i, "time": time.Now()},
            })
        }
        stream.Close()
    }))
}

SSEEvent Fields

Client (JavaScript)

const source = new EventSource('/events');
source.addEventListener('update', (e) => {
    const data = JSON.parse(e.data);
    console.log(data.count);
});

The stream automatically closes when the client disconnects.