DMAC/server/internal/pkg/websocket/connect.go

// Package websocket sets up websocket connections with clients and allows live reactor readouts.
package websocket

// creates websocket server and upgrades incoming connections
import (
	"encoding/json"
	"fmt"
	"net/http"

	ws "github.com/gorilla/websocket"
)

type ReactorTest struct {
	Id   int    `json:"id"`
	Name string `json:"name"`
}

type WebSocket struct {
	// dummy struct for interface
	N string
}

func New() *WebSocket {
	return &WebSocket{}
}

func (s *WebSocket) Start() {
	fmt.Println("Starting ws server!")
	setupRoutes()
	http.ListenAndServe(":8080", nil)
}

// default opts allow all origins
var upgrader = ws.Upgrader{
	CheckOrigin: func(r *http.Request) bool { return true },
}

// reader
func reader(conn *ws.Conn) {

	for {
		// read forever
		//messageType, p, err := conn.ReadMessage()
		_, p, err := conn.ReadMessage()

		if err != nil {
			if ws.IsCloseError(err, ws.CloseNormalClosure, ws.CloseGoingAway) {
				// normally closed
				return
			}
			panic(err)
		}
		fmt.Printf("Msg: %s\n", string(p))
	}
}

func serverWs(w http.ResponseWriter, r *http.Request) {
	fmt.Println(r.Host)

	websocket, err := upgrader.Upgrade(w, r, nil)

	if err != nil {
		panic(err)
	}

	// try sending reactor
	t1 := &ReactorTest{Id: 1111, Name: "test1"}
	t2 := &ReactorTest{Id: 1112, Name: "test2"}
	t3 := &ReactorTest{Id: 1113, Name: "test3"}
	n := []*ReactorTest{t1, t2, t3}
	msg, err := json.Marshal(n)
	if err != nil {
		panic(err)
	}
	// pass to connection
	if err := websocket.WriteMessage(ws.TextMessage, msg); err != nil {
		panic(err)
	}

	// pass to reader
	reader(websocket)
}

func setupRoutes() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintf(w, "Simple Server")
	})

	http.HandleFunc("/ws", serverWs)
}