add websocket handler

go.mod

 module github.com/sktt1ryze/ygopro-proxy
 
 go 1.17
+
+require github.com/gorilla/websocket v1.5.0 // indirect

go.sum

+github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
+github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=

proxy.go

@@ -2,8 +2,71 @@ package main
 
 import (
 	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/gorilla/websocket"
 )
 
+const TARGET_PORT = ":8000"
+const PROXY_PORT = ":3344"
+
+var upgrader = websocket.Upgrader{
+	ReadBufferSize:  0x1000,
+	WriteBufferSize: 0x1000,
+}
+
+func homePage(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, "Home Page")
+}
+
+func ygoEndpoint(w http.ResponseWriter, r *http.Request) {
+	upgrader.CheckOrigin = wsChecker
+
+	ws, err := upgrader.Upgrade(w, r, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer ws.Close()
+
+	log.Println("Websocket connected")
+
+	proxyHandler(ws)
+}
+
+func proxyHandler(ws *websocket.Conn) {
+	// todo: spawn channel
+
+	for {
+		messageType, buf, err := ws.ReadMessage()
+		if err != nil {
+			log.Fatal(err)
+			return
+		}
+
+		if messageType == websocket.CloseMessage {
+			log.Println("Websocket closed")
+			return
+		}
+
+		fmt.Println(string(buf))
+
+		if err := ws.WriteMessage(messageType, buf); err != nil {
+			log.Fatal(err)
+			return
+		}
+	}
+}
+
+func wsChecker(r *http.Request) bool { return true }
+
+func setupRoutes() {
+	http.HandleFunc("/", homePage)
+	http.HandleFunc("/ygo", ygoEndpoint)
+}
+
 func main() {
-  fmt.Println("hello, ygopro-proxy")
+	setupRoutes()
+
+	log.Fatal(http.ListenAndServe(TARGET_PORT, nil))
 }