whiteboard/hub.go at main · walshyb/whiteboard · GitHub

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package main

import (
  "log"
  "context"

  "github.com/redis/go-redis/v9"
  "go.mongodb.org/mongo-driver/v2/mongo"
	"google.golang.org/protobuf/proto"
	 events "github.com/walshyb/whiteboard/proto"
)

type Hub struct {
  clients map[*Client]bool
  register chan *Client
  unregister chan *Client
  broadcast chan *events.ClientMessage
  redis *redis.Client
  mongo *mongo.Client
  serverId string
  ctx context.Context
}

func (hub *Hub) run() {
  for {
    select {
    case client := <-hub.register:
      hub.clients[client] = true
      handshake := events.ServerMessage{
        ClientId: client.id,
      }
      hub.redis.Set(hub.ctx, client.id, client.name, 0).Err()
      client.handshake <- &handshake
    case client := <- hub.unregister:
      if _, ok := hub.clients[client]; ok {
        delete(hub.clients, client)
        close(client.handshake)
        close(client.send)

        // Remove client from active list of connections
        _, err := hub.redis.Del(hub.ctx, client.id).Result()
        if err != nil {
          log.Fatalf("Error deleting client: %v", err)
        }

        payload := events.ServerMessage{
					EventType: &events.ServerMessage_ClientDisconnect {
						ClientDisconnect: &events.ClientDisconnectEvent{
							ClientName: client.name,
						},
					},
        }

        for c := range hub.clients {
          select {
          case c.send <- &payload:
          default:
            close(c.send)
            delete(hub.clients, c)
          }
        }
      }
    case clientMessage := <-hub.broadcast:
      if clientMessage.ClientId == "" {
        continue
      }

      clientName, err := hub.redis.Get(hub.ctx, clientMessage.ClientId).Result()
      if err != nil {
        println("error getting client ID from redis")
				continue
      }

      serverMessage := &events.ServerMessage{
				SenderName: clientName,
      }

			if clientMessage.ServerId == nil {
				log.Println("ClientMessage missing ServerId")
				continue
			}
			serverId := *clientMessage.ServerId

			switch event := clientMessage.GetEventType().(type) {
				case *events.ClientMessage_AddShape:
					// Only write to mongo db if server ID of message sender is same as current
					if serverId != hub.serverId {
						continue
					}

					addEvent := event.AddShape
					shape, err := AddShape(hub, addEvent.Data)
					if err != nil {
						println("error adding shape", err)
						continue
					}
					serverMessage.EventType = &events.ServerMessage_AddShape{
						AddShape: &events.AddShapeEvent{
							Data: shape,
						},
					}
				case *events.ClientMessage_MouseEvent:
					serverMessage.EventType = &events.ServerMessage_MouseEvent {
						MouseEvent: clientMessage.GetMouseEvent(),
					}
				default:
					continue
			}

      for client := range hub.clients {
        if client.id == clientMessage.GetClientId() {
          continue
        }

        select {
        case client.send <- serverMessage:
        default:
          close(client.send)
          delete(hub.clients, client)
        }
      }
    }
  }
}

func (hub *Hub) subscribeRedis() {
  sub := hub.redis.Subscribe(hub.ctx, "mouse_events")
  ch := sub.Channel()

  go func() {
    for msg := range ch {
      var m events.ClientMessage

      //if m.ServerId == hub.serverId {
      //  continue
      //}

      if err := proto.Unmarshal([]byte(msg.Payload), &m); err != nil {
        continue
      }

      // Broadcast to our local clients
      hub.broadcast <- &m
    }
  }()
}