Only refetch changed resources when receive a "refreshResource" event

server/events/events.go

@@ -37,12 +37,33 @@ type KeepAlive struct {
 	TS int64 `json:"ts"`
 }
 
-type RefreshResource struct {
-	baseEvent
-	Resource string `json:"resource"`
-}
-
 type ServerStart struct {
 	baseEvent
 	StartTime time.Time `json:"startTime"`
 }
+
+const Any = "*"
+
+type RefreshResource struct {
+	baseEvent
+	resources map[string][]string
+}
+
+func (rr *RefreshResource) With(resource string, ids ...string) *RefreshResource {
+	if rr.resources == nil {
+		rr.resources = make(map[string][]string)
+	}
+	for i := range ids {
+		rr.resources[resource] = append(rr.resources[resource], ids[i])
+	}
+	return rr
+}
+
+func (rr *RefreshResource) Data(evt Event) string {
+	if rr.resources == nil {
+		return `{"*":"*"}`
+	}
+	r := evt.(*RefreshResource)
+	data, _ := json.Marshal(r.resources)
+	return string(data)
+}

server/events/events_test.go

@@ -5,17 +5,42 @@ import (
 	. "github.com/onsi/gomega"
 )
 
-var _ = Describe("Event", func() {
-	It("marshals Event to JSON", func() {
-		testEvent := TestEvent{Test: "some data"}
-		data := testEvent.Data(&testEvent)
-		Expect(data).To(Equal(`{"Test":"some data"}`))
-		name := testEvent.Name(&testEvent)
-		Expect(name).To(Equal("testEvent"))
+var _ = Describe("Events", func() {
+	Describe("Event", func() {
+		type TestEvent struct {
+			baseEvent
+			Test string
+		}
+
+		It("marshals Event to JSON", func() {
+			testEvent := TestEvent{Test: "some data"}
+			data := testEvent.Data(&testEvent)
+			Expect(data).To(Equal(`{"Test":"some data"}`))
+			name := testEvent.Name(&testEvent)
+			Expect(name).To(Equal("testEvent"))
+		})
+	})
+
+	Describe("RefreshResource", func() {
+		var rr *RefreshResource
+		BeforeEach(func() {
+			rr = &RefreshResource{}
+		})
+
+		It("should render to full refresh if event is empty", func() {
+			data := rr.Data(rr)
+			Expect(data).To(Equal(`{"*":"*"}`))
+		})
+		It("should group resources based on name", func() {
+			rr.With("album", "al-1").With("song", "sg-1").With("artist", "ar-1")
+			rr.With("album", "al-2", "al-3").With("song", "sg-2").With("artist", "ar-2")
+			data := rr.Data(rr)
+			Expect(data).To(Equal(`{"album":["al-1","al-2","al-3"],"artist":["ar-1","ar-2"],"song":["sg-1","sg-2"]}`))
+		})
+		It("should send a * for when Any is used as id", func() {
+			rr.With("album", Any)
+			data := rr.Data(rr)
+			Expect(data).To(Equal(`{"album":["*"]}`))
+		})
 	})
 })
-
-type TestEvent struct {
-	baseEvent
-	Test string
-}