Change format of events sent by server, leveraging event type and id

server/events/sse.go

@@ -19,8 +19,15 @@ type Broker interface {
 
 const keepAliveFrequency = 15 * time.Second
 
+var eventId uint32
+
 type (
-	messageChan chan []byte
+	message struct {
+		ID    uint32
+		Event string
+		Data  string
+	}
+	messageChan chan message
 	clientsChan chan client
 	client      struct {
 		address   string
@@ -63,26 +70,19 @@ func NewBroker() Broker {
 	return broker
 }
 
-func (broker *broker) SendMessage(event Event) {
-	pkg := broker.preparePackage(event)
-
-	log.Trace("Broker received new event", "name", event.EventName(), "event", string(pkg))
-	broker.notifier <- pkg
+func (broker *broker) SendMessage(evt Event) {
+	msg := broker.preparePackage(evt)
+	log.Trace("Broker received new event", "event", msg)
+	broker.notifier <- msg
 }
 
-var eventId uint32
-
-func (broker *broker) preparePackage(event Event) []byte {
-	pkg := struct {
-		Event `json:"data"`
-		Id    uint32 `json:"id"`
-		Name  string `json:"name"`
-	}{}
-	pkg.Id = atomic.AddUint32(&eventId, 1)
-	pkg.Name = event.EventName()
-	pkg.Event = event
-	data, _ := json.Marshal(pkg)
-	return data
+func (broker *broker) preparePackage(event Event) message {
+	pkg := message{}
+	pkg.ID = atomic.AddUint32(&eventId, 1)
+	pkg.Event = event.EventName()
+	data, _ := json.Marshal(event)
+	pkg.Data = string(data)
+	return pkg
 }
 
 func (broker *broker) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
@@ -133,8 +133,8 @@ func (broker *broker) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 		// Write to the ResponseWriter
 		// Server Sent Events compatible
 		event := <-client.channel
-		log.Trace(ctx, "Sending event to client", "event", string(event), "client", client.String())
-		_, _ = fmt.Fprintf(rw, "data: %s\n\n", event)
+		log.Trace(ctx, "Sending event to client", "event", event, "client", client.String())
+		_, _ = fmt.Fprintf(rw, "id: %d\nevent: %s\ndata: %s\n\n", event.ID, event.Event, event.Data)
 
 		// Flush the data immediately instead of buffering it for later.
 		flusher.Flush()
@@ -157,7 +157,7 @@ func (broker *broker) listen() {
 			s.channel <- broker.preparePackage(&ServerStart{serverStart})
 
 		case s := <-broker.closingClients:
-			// A client has dettached and we want to
+			// A client has detached and we want to
 			// stop sending them messages.
 			delete(broker.clients, s)
 			log.Debug("Removed client from event broker", "numClients", len(broker.clients), "client", s.String())
@@ -166,7 +166,7 @@ func (broker *broker) listen() {
 			// We got a new event from the outside!
 			// Send event to all connected clients
 			for client := range broker.clients {
-				log.Trace("Putting event on client's queue", "client", client.String(), "event", string(event))
+				log.Trace("Putting event on client's queue", "client", client.String(), "event", event)
 				client.channel <- event
 			}
 

ui/src/actions/serverEvents.js

@@ -1,17 +1,11 @@
-export const EVENT_SCAN_STATUS = 'EVENT_SCAN_STATUS'
-export const EVENT_SERVER_START = 'EVENT_SERVER_START'
+export const EVENT_SCAN_STATUS = 'scanStatus'
+export const EVENT_SERVER_START = 'serverStart'
 
-const actionsMap = {
-  scanStatus: EVENT_SCAN_STATUS,
-  serverStart: EVENT_SERVER_START,
-}
-
-export const processEvent = (data) => {
-  let type = actionsMap[data.name]
-  if (!type) type = data.name
+export const processEvent = (type, event) => {
+  const data = JSON.parse(event)
   return {
     type,
-    data: data.data,
+    data: data,
   }
 }
 

ui/src/eventStream.js

@@ -13,7 +13,7 @@ let timeout = null
 
 const getEventStream = async () => {
   if (es === null) {
-    return httpClient(`${REST_URL}/keepalive/`).then(() => {
+    return httpClient(`${REST_URL}/keepalive/eventSource`).then(() => {
       es = new EventSource(
         baseUrl(`/app/api/events?jwt=${localStorage.getItem('token')}`)
       )
@@ -53,29 +53,34 @@ const setDispatch = (dispatchFunc) => {
   dispatch = dispatchFunc
 }
 
+const eventHandler = throttle(
+  (event) => {
+    if (event.type !== 'keepAlive') {
+      dispatch(processEvent(event.type, event.data))
+    }
+    setTimeout(defaultIntervalCheck) // Reset timeout on every received message
+  },
+  100,
+  { trailing: true }
+)
+
 const startEventStream = async () => {
   setTimeout(currentIntervalCheck)
   if (!localStorage.getItem('token')) {
     console.log('Cannot create a unauthenticated EventSource connection')
-    return
+    return Promise.reject()
   }
   getEventStream().then((newStream) => {
-    newStream.onmessage = throttle(
-      (msg) => {
-        const data = JSON.parse(msg.data)
-        if (data.name !== 'keepAlive') {
-          dispatch(processEvent(data))
-        }
-        setTimeout(defaultIntervalCheck) // Reset timeout on every received message
-      },
-      100,
-      { trailing: true }
-    )
+    newStream.addEventListener('serverStart', eventHandler)
+    newStream.addEventListener('scanStatus', eventHandler)
+    newStream.addEventListener('keepAlive', eventHandler)
     newStream.onerror = (e) => {
+      console.log('EventStream error', e)
       setTimeout(reconnectIntervalCheck)
       dispatch(serverDown())
     }
     es = newStream
+    return es
   })
 }