go-zero+WebRTCでリアルタイムビデオコミュニケーションを実現

import (
    "bytes"
    "encoding/json"
    "github.com/creasty/defaults"
    "github.com/go-chi/chi/v5"
    "github.com/gorilla/websocket"
    "github.com/rs/zerolog"
    "github.com/rs/zerolog/log"
    "github.com/segmentio/ksuid"
    "math/rand"
    "net/http"
    "sync"
    "time"
)

type SignalServer struct {
    hub *Hub
    mu  sync.Mutex
}

func NewSignalServer() *SignalServer {
    return &SignalServer{
        hub: newHub(),
    }
}

func (s *SignalServer) routes() *chi.Mux {
    r := chi.NewRouter()
    r.Handle("/ws", websocket.Handler(s.handleWebSocket))
    return r
}

func (s *SignalServer) handleWebSocket(conn *websocket.Conn) {
    sessionId := ksuid.New().String()
    client := &Client{
        id:   sessionId,
        conn: conn,
        send: make(chan []byte, 256),
        hub:  s.hub,
    }
    s.hub.register <- client
    go client.writePump()

    for {
        _, message, err := conn.ReadMessage()
        if err != nil {
            break
        }
        s.handleMessage(client, message)
    }

    s.hub.unregister <- client
    conn.Close()
}

func (s *SignalServer) handleMessage(client *Client, data []byte) {
    log.Debug().Msgf("received message: %s", data)
    message := &SignalingMessage{}
    if err := json.Unmarshal(data, message); err != nil {
        log.Error().Msgf("failed to unmarshal data: %s", err.Error())
        return
    }

    switch message.Type {
    case "register":
        s.handleRegister(client, message)
    case "offer":
        s.hub.broadcast <- &MessageData{
            SenderId: client.id,
            Type:     "offer",
            Payload:  message.Payload,
        }
    case "answer":
        s.hub.broadcast <- &MessageData{
            SenderId: client.id,
            Type:     "answer",
            Payload:  message.Payload,
        }
    case "candidate":
        s.hub.broadcast <- &MessageData{
            SenderId: client.id,
            Type:     "candidate",
            Payload:  message.Payload,
        }
    default:
        log.Error().Msgf("unknown message type: %s", message.Type)
    }
}

func (s *SignalServer) handleRegister(client *Client, message *SignalingMessage) {
    room := message.Payload
    s.mu.Lock()
    defer s.mu.Unlock()
    if _, ok := s.hub.rooms[room]; !ok {
        s.hub.rooms[room] = make(map[string]*Client)
    }
    s.hub.rooms[room][client.id] = client
    log.Debug().Msgf("client %s registered in room %s", client.id, room)
}

func (p *Peer) generateOffer() (*sdp.SessionDescription, error) {
    offer, err := p.pconn.CreateOffer(nil)
    if err != nil {
        return nil, err
    }

    if err := p.pconn.SetLocalDescription(offer); err != nil {
        return nil, err
    }

    return offer, nil
}

func (p *Peer) handleOffer(payload string) (*sdp.SessionDescription, error) {
    offer, err := webrtc.NewSessionDescription(sdp.SessionDescriptionProtocolType, payload)
    if err != nil {
        return nil, err
    }
    if err := p.pconn.SetRemoteDescription(offer); err != nil {
        return nil, err
    }

    answer, err := p.pconn.CreateAnswer(nil)
    if err != nil {
        return nil, err
    }

    if err := p.pconn.SetLocalDescription(answer); err != nil {
        return nil, err
    }

    return answer, nil
}

func (p *Peer) handleAnswer(payload string) error {
    answer, err := webrtc.NewSessionDescription(sdp.SessionDescriptionProtocolType, payload)
    if err != nil {
        return err
    }
    if err := p.pconn.SetRemoteDescription(answer); err != nil {
        return err
    }
    return nil
}