Release catalyst

websocket.go

@@ -0,0 +1,84 @@
+package catalyst
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"sync"
+
+	"github.com/arangodb/go-driver"
+	"github.com/gin-gonic/gin"
+	"github.com/gobwas/ws"
+	"github.com/gobwas/ws/wsutil"
+	"github.com/google/uuid"
+
+	"github.com/SecurityBrewery/catalyst/bus"
+)
+
+type websocketBroker struct {
+	clients map[string]chan []byte
+	mu      sync.Mutex
+}
+
+func (wb *websocketBroker) Publish(b []byte) {
+	for _, channel := range wb.clients {
+		channel <- b
+	}
+}
+
+func (wb *websocketBroker) CloseSocket(id string) {
+	wb.mu.Lock()
+	if channel, ok := wb.clients[id]; ok {
+		close(channel)
+		delete(wb.clients, id)
+	}
+	wb.mu.Unlock()
+}
+
+func (wb *websocketBroker) NewWebsocket() (string, chan []byte) {
+	id := uuid.New().String()
+	channel := make(chan []byte, 10)
+	wb.mu.Lock()
+	wb.clients[id] = channel
+	wb.mu.Unlock()
+	return id, channel
+}
+
+func handleWebSocket(catalystBus *bus.Bus) func(ctx *gin.Context) {
+	broker := websocketBroker{clients: map[string]chan []byte{}}
+
+	// send all messages from bus to websocket
+	err := catalystBus.SubscribeUpdate(func(ids []driver.DocumentID) {
+		b, err := json.Marshal(map[string]interface{}{
+			"action": "update",
+			"ids":    ids,
+		})
+		if err != nil {
+			return
+		}
+
+		broker.Publish(b)
+	})
+	if err != nil {
+		log.Println(err)
+	}
+
+	return func(ctx *gin.Context) {
+		conn, _, _, err := ws.UpgradeHTTP(ctx.Request, ctx.Writer)
+		if err != nil {
+			ctx.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"error": "upgrade failed"})
+			return
+		}
+
+		go func() {
+			defer conn.Close()
+
+			id, messages := broker.NewWebsocket()
+			for msg := range messages {
+				if err := wsutil.WriteServerMessage(conn, ws.OpText, msg); err != nil {
+					broker.CloseSocket(id)
+				}
+			}
+		}()
+	}
+}