lupus-lite/routes/ws.go

package routes

import (
	"log"

	"github.com/aziis98/lupus-lite/events"
	"github.com/aziis98/lupus-lite/util"
	"github.com/gofiber/fiber/v2"
	"github.com/gofiber/websocket/v2"
)

// func (s *Server) websocketHandler(handler func(c *fiber.Ctx) (interface{}, error)) fiber.Handler {
// 	return websocket.New(func(c *websocket.Conn) {
// 		clientId := util.GenerateRandomString(10)

// 		partitaUid := c.Params("partita")
// 		log.Printf("[%v] Connection started", clientId)

// 		done := make(chan error)
// 		clientListener := s.eventBus.Subscribe(
// 			database.OnPartitaPlayerJoin(partitaUid),
// 			func(e interface{}) {
// 				partita, err := s.db.GetPartita(partitaUid)
// 				if err != nil {
// 					done <- err
// 					return
// 				}

// 				log.Printf(`[%v] Sent message`, clientId)
// 				if err := c.WriteJSON(partita.Players); err != nil {
// 					done <- err
// 					return
// 				}
// 			},
// 		)
// 		defer func() {
// 			s.eventBus.Unsubscribe(clientListener)
// 			log.Printf("[%v] Connection closed", clientId)
// 		}()

// 		for {
// 			_, _, err := c.ReadMessage()
// 			if err != nil {
// 				if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
// 					log.Printf("[%v] Error: %v", clientId, err)
// 				}
// 				return
// 			}

// 			select {
// 			case err := <-done:
// 				if err != nil {
// 					log.Printf(`[%v] Error: %v`, clientId, err)
// 				}
// 				return
// 			case <-time.After(1 * time.Second):
// 			}
// 		}
// 	})
// }

// func (s *Server) registerEventBinding(event string, process func(c *fiber.Ctx, e any) (any, error)) fiber.Handler {
// 	return websocket.New(func(c *websocket.Conn) {
// 		clientId := util.GenerateRandomString(10)
// 		log.Printf("[%v] Connection started", clientId)
// 		done := make(chan error)
// 		clientListener := s.eventBus.Subscribe(
// 			event,
// 			func(e interface{}) {
// 				partita, err := s.db.GetPartita(partitaUid)
// 				if err != nil {
// 					done <- err
// 					return
// 				}

// 				log.Printf(`[%v] Sent message`, clientId)
// 				if err := c.WriteJSON(partita.Players); err != nil {
// 					done <- err
// 					return
// 				}
// 			},
// 		)
// 		defer func() {
// 			s.eventBus.Unsubscribe(clientListener)
// 			log.Printf("[%v] Connection closed", clientId)
// 		}()

// 		for {
// 			_, _, err := c.ReadMessage()
// 			if err != nil {
// 				if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
// 					log.Printf("[%v] Error: %v", clientId, err)
// 				}
// 				return
// 			}

// 			select {
// 			case err := <-done:
// 				if err != nil {
// 					log.Printf(`[%v] Error: %v`, clientId, err)
// 				}
// 				return
// 			case <-time.After(1 * time.Second):
// 			}
// 		}
// 	})
// }

type clientMessage struct {
	Type  string `json:"type"`
	Event string `json:"event"`
}

type serverMessage struct {
	Event string `json:"event"`
	Data  any    `json:"data"`
}

// registerEventBinder creates a WebSocket handler that can subscribe the socket to some events generated on the server, for example a message from the client like { type: "subscribe", event: "foo" } binds the connection to the event "foo" and forwards events and the associated data to client as JSON.
func registerEventBinder(eb *events.EventBus) fiber.Handler {
	return websocket.New(func(c *websocket.Conn) {
		clientId := util.GenerateRandomString(10)

		log.Printf("[%v] Connection started", clientId)
		defer log.Printf("[%v] Connection closed", clientId)

		listeners := []*events.Listener{}
		defer func() {
			for _, l := range listeners {
				eb.Unsubscribe(l)
			}
		}()

		done := make(chan error)
		for {
			var msg clientMessage
			if err := c.ReadJSON(&msg); err != nil {
				log.Printf(`[%v] Read error: %v`, clientId, err)
				return
			}

			log.Printf("[%v] Received: %v", clientId, msg)

			switch msg.Type {
			case "subscribe":
				newListener := eb.Subscribe(
					msg.Event,
					func(e interface{}) {
						log.Printf(`[%v] Sent message`, clientId)
						if err := c.WriteJSON(serverMessage{
							Event: msg.Event,
							Data:  e,
						}); err != nil {
							log.Printf(`[%v] Write error: %v`, clientId, err)
							done <- err
						}
					},
				)
				listeners = append(listeners, newListener)
			default:
				log.Printf("[%v] Unknown message type %q", clientId, msg.Type)
				return
			}

			select {
			case err := <-done:
				if err != nil {
					return
				}
			default:
			}
		}
	})
}

func (s *Server) EventRoute(r fiber.Router) {
	r.Use("/ws", func(c *fiber.Ctx) error {
		if websocket.IsWebSocketUpgrade(c) {
			c.Locals("allowed", true)
			return c.Next()
		}
		return fiber.ErrUpgradeRequired
	})

	r.Get("/ws", registerEventBinder(s.eventBus))
}