Golang 開発: WebRTC ベースのビデオ通話アプリケーションの実装

package main

import (
    "encoding/json"
    "fmt"
    "log"
    "net/http"

    "github.com/gorilla/websocket"
    "github.com/pion/webrtc/v3"
)

var (
    upgrader = websocket.Upgrader{}
    peers    = map[*websocket.Conn]*webrtc.PeerConnection{}
)

func main() {
    http.HandleFunc("/offer", handleOffer)
    http.HandleFunc("/answer", handleAnswer)
    http.HandleFunc("/ws", handleWebSocket)
    log.Fatal(http.ListenAndServe(":8080", nil))
}

func handleOffer(w http.ResponseWriter, r *http.Request) {
    conn, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Println(err)
        return
    }
    defer conn.Close()

    pc, err := webrtc.NewPeerConnection(webrtc.Configuration{})
    if err != nil {
        log.Println(err)
        return
    }

    pc.OnICECandidate(func(candidate *webrtc.ICECandidate) {
        if candidate != nil {
            jsonCandidate, _ := json.Marshal(candidate.ToJSON())
            conn.WriteMessage(websocket.TextMessage, jsonCandidate)
        }
    })

    pc.OnTrack(func(track *webrtc.TrackRemote, receiver *webrtc.RTPReceiver) {
        go func() {
            for {
                _, _, _ = track.ReadRTP()
            }
        }()
    })

    pc.AddTransceiver(webrtc.RTPCodecTypeVideo)

    peers[conn] = pc

    for {
        _, message, err := conn.ReadMessage()
        if err != nil {
            log.Println(err)
            delete(peers, conn)
            return
        }
        pc.AddICECandidate(webrtc.ICECandidateInit{
            Candidate: string(message),
        })
    }
}

// handleAnswer 处理answer请求
func handleAnswer(w http.ResponseWriter, r *http.Request) {
    var answer struct {
        Candidate string `json:"candidate"`
    }
    err := json.NewDecoder(r.Body).Decode(&answer)
    if err != nil {
        http.Error(w, err.Error(), http.StatusBadRequest)
        return
    }

    conn, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Println(err)
        return
    }
    defer conn.Close()

    pc := peers[conn]
    pc.AddICECandidate(webrtc.ICECandidateInit{
        Candidate: answer.Candidate,
    })
}

// handleWebSocket 处理WebSocket连接请求
func handleWebSocket(w http.ResponseWriter, r *http.Request) {
    conn, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Println(err)
        return
    }
    defer conn.Close()

    pc, err := webrtc.NewPeerConnection(webrtc.Configuration{})
    if err != nil {
        log.Println(err)
        return
    }

    pc.OnICECandidate(func(candidate *webrtc.ICECandidate) {
        if candidate != nil {
            jsonCandidate, _ := json.Marshal(candidate.ToJSON())
            conn.WriteMessage(websocket.TextMessage, jsonCandidate)
        }
    })

    pc.OnTrack(func(track *webrtc.TrackRemote, receiver *webrtc.RTPReceiver) {
        go func() {
            for {
                _, _, _ = track.ReadRTP()
            }
        }()
    })

    offer, err := pc.CreateOffer(nil)
    if err != nil {
        log.Println(err)
        return
    }

    err = pc.SetLocalDescription(offer)
    if err != nil {
        log.Println(err)
        return
    }

    conn.WriteJSON(offer)

    peers[conn] = pc
}

go build -o video-call-app
./video-call-app