add keepalive messages

controllers/invoicestream.ctrl.go

@@ -2,6 +2,7 @@ package controllers
 
 import (
 	"net/http"
+	"time"
 
 	"github.com/getAlby/lndhub.go/common"
 	"github.com/getAlby/lndhub.go/db/models"
@@ -16,6 +17,11 @@ type InvoiceStreamController struct {
 	svc *service.LndhubService
 }
 
+type InvoiceEventWrapper struct {
+	Type    string           `json:"type"`
+	Invoice *IncomingInvoice `json:"invoice, omitempty"`
+}
+
 func NewInvoiceStreamController(svc *service.LndhubService) *InvoiceStreamController {
 	return &InvoiceStreamController{svc: svc}
 }
@@ -31,6 +37,7 @@ func (controller *InvoiceStreamController) StreamInvoices(c echo.Context) error
 	ctx := c.Request().Context()
 	upgrader := websocket.Upgrader{}
 	upgrader.CheckOrigin = func(r *http.Request) bool { return true }
+	ticker := time.NewTicker(30 * time.Second)
 	ws, err := upgrader.Upgrade(c.Response(), c.Request(), nil)
 	if err != nil {
 		return err
@@ -41,9 +48,17 @@ SocketLoop:
 		select {
 		case <-ctx.Done():
 			break SocketLoop
+		case <-ticker.C:
+			err := ws.WriteJSON(&InvoiceEventWrapper{Type: "keepalive"})
+			if err != nil {
+				controller.svc.Logger.Error(err)
+				break SocketLoop
+			}
 		case invoice := <-invoiceChan:
 			err := ws.WriteJSON(
-				&IncomingInvoice{
+				&InvoiceEventWrapper{
+					Type: "invoice",
+					Invoice: &IncomingInvoice{
 						PaymentHash:    invoice.RHash,
 						PaymentRequest: invoice.PaymentRequest,
 						Description:    invoice.Memo,
@@ -52,7 +67,7 @@ SocketLoop:
 						Type:           common.InvoiceTypeUser,
 						Amount:         invoice.Amount,
 						IsPaid:         invoice.State == common.InvoiceStateSettled,
-				})
+					}})
 			if err != nil {
 				controller.svc.Logger.Error(err)
 				break SocketLoop