Implement controller and viewer communication using WebSockets

main.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"encoding/json"
+	"github.com/gorilla/websocket"
+	"log"
+	"net/http"
+)
+
+var upgrader = websocket.Upgrader{
+	WriteBufferSize: 4096,
+	ReadBufferSize:  0,
+	CheckOrigin: func(r *http.Request) bool {
+		return true
+	},
+}
+
+func main() {
+	var nudges = make(chan [2]int)
+
+	go func() {
+		mux := http.NewServeMux()
+		mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Add("Access-Control-Allow-Origin", "*")
+			w.Header().Add("Access-Control-Allow-Headers", "*")
+			w.Header().Add("Access-Control-Allow-Methods", "*")
+			switch r.Method {
+			case "OPTIONS":
+				w.WriteHeader(http.StatusNoContent)
+				return
+			case "POST":
+				var nudge [2]int
+				switch r.Header.Get("Content-Type") {
+				case "application/json":
+					var decoder = json.NewDecoder(r.Body)
+					if err := decoder.Decode(&nudge); err != nil {
+						log.Println(err)
+						w.WriteHeader(http.StatusBadRequest)
+						return
+					}
+				default:
+					w.WriteHeader(http.StatusBadRequest)
+					return
+				}
+				nudges <- nudge
+				w.WriteHeader(http.StatusNoContent)
+			default:
+				w.WriteHeader(http.StatusMethodNotAllowed)
+			}
+		})
+		log.Println(http.ListenAndServe(":8080", mux))
+	}()
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		con, err := upgrader.Upgrade(w, r, nil)
+		if err != nil {
+			log.Println(err)
+		}
+		for n := range nudges {
+			log.Println(n)
+			err := con.WriteJSON(n)
+			if err != nil {
+				log.Println(err)
+			}
+		}
+	})
+	log.Println(http.ListenAndServe("127.0.0.1:8081", mux))
+}