finish basic function and test pass

proxy.go

 package main
 
 import (
+	"bufio"
 	"fmt"
 	"log"
+	"net"
 	"net/http"
+	"sync"
 
 	"github.com/gorilla/websocket"
 )
 
 const TARGET_PORT = ":8000"
 const PROXY_PORT = ":3344"
+const CHANNEL_SIZE = 0x1000
+const BUFFER_SIZE = 0x1000
 
 var upgrader = websocket.Upgrader{
 	ReadBufferSize:  0x1000,
@@ -21,6 +26,8 @@ func homePage(w http.ResponseWriter, r *http.Request) {
 }
 
 func ygoEndpoint(w http.ResponseWriter, r *http.Request) {
+	var wg sync.WaitGroup
+
 	upgrader.CheckOrigin = wsChecker
 
 	ws, err := upgrader.Upgrade(w, r, nil)
@@ -31,31 +38,67 @@ func ygoEndpoint(w http.ResponseWriter, r *http.Request) {
 
 	log.Println("Websocket connected")
 
-	proxyHandler(ws)
-}
+	tcp, err := net.Dial("tcp", "127.0.0.1"+PROXY_PORT)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer tcp.Close()
 
-func proxyHandler(ws *websocket.Conn) {
-	// todo: spawn channel
+	wg.Add(2)
+	go wsProxy(ws, &tcp, &wg)
+	go tcpProxy(&tcp, ws, &wg)
+	wg.Wait()
+}
 
+func wsProxy(ws *websocket.Conn, tcp *net.Conn, wg *sync.WaitGroup) {
 	for {
 		messageType, buf, err := ws.ReadMessage()
 		if err != nil {
 			log.Fatal(err)
-			return
+			break
 		}
 
 		if messageType == websocket.CloseMessage {
 			log.Println("Websocket closed")
-			return
+			break
 		}
 
-		fmt.Println(string(buf))
+		log.Println("websocket to tcp: " + string(buf))
 
-		if err := ws.WriteMessage(messageType, buf); err != nil {
+		writer := bufio.NewWriter(*tcp)
+		buffer := make([]byte, BUFFER_SIZE)
+
+		_, err = writer.Write(buffer)
+		if err != nil {
 			log.Fatal(err)
-			return
+			break
 		}
 	}
+
+	wg.Done()
+}
+
+func tcpProxy(tcp *net.Conn, ws *websocket.Conn, wg *sync.WaitGroup) {
+	for {
+		reader := bufio.NewReader(*tcp)
+		buffer := make([]byte, BUFFER_SIZE)
+
+		_, err := reader.Read(buffer)
+		if err != nil {
+			log.Fatal(err)
+			break
+		}
+
+		log.Println("tcp to websocket: " + string(buffer))
+
+		err = ws.WriteMessage(websocket.TextMessage, buffer) // temporary TextMessage, should be BinaryMessage in ygopro
+		if err != nil {
+			log.Fatal(err)
+			break
+		}
+	}
+
+	wg.Done()
 }
 
 func wsChecker(r *http.Request) bool { return true }