improve sse for userlog

Signed-off-by: jkoberg <jkoberg@owncloud.com>

services/sse/pkg/service/service.go

@@ -1,6 +1,7 @@
 package service
 
 import (
+	"encoding/json"
 	"net/http"
 
 	revactx "github.com/cs3org/reva/v2/pkg/ctx"
@@ -12,6 +13,12 @@ import (
 	"github.com/owncloud/ocis/v2/services/sse/pkg/config"
 )
 
+// ServerSentEvent is the data structure sent by the sse service
+type ServerSentEvent struct {
+	Type string          `json:"type"`
+	Data json.RawMessage `json:"data"`
+}
+
 // SSE defines implements the business logic for Service.
 type SSE struct {
 	c         *config.Config
@@ -45,20 +52,25 @@ func (s SSE) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 }
 
 // ListenForEvents listens for events
-func (s SSE) ListenForEvents() error {
+func (s SSE) ListenForEvents() {
 	for e := range s.evChannel {
 		switch ev := e.Event.(type) {
 		default:
 			s.l.Error().Interface("event", ev).Msg("unhandled event")
 		case events.SendSSE:
+			b, err := json.Marshal(ServerSentEvent{
+				Type: ev.Type,
+				Data: ev.Message,
+			})
+			if err != nil {
+				s.l.Error().Interface("event", ev).Msg("cannot marshal event")
+				continue
+			}
 			s.sse.Publish(ev.UserID, &sse.Event{
-				Event: []byte(ev.Type),
-				Data:  ev.Message,
+				Data: b,
 			})
 		}
 	}
-
-	return nil
 }
 
 // HandleSSE is the GET handler for events