add file-sharing to go-peer

go-peer/chatroom.go

@@ -1,8 +1,12 @@
 package main
 
 import (
+	"bufio"
 	"context"
+	"encoding/binary"
+	"fmt"
 
+	"github.com/libp2p/go-libp2p/core/host"
 	"github.com/libp2p/go-libp2p/core/peer"
 
 	pubsub "github.com/libp2p/go-libp2p-pubsub"
@@ -19,13 +23,15 @@ type ChatRoom struct {
 	Messages    chan *ChatMessage
 	SysMessages chan *ChatMessage
 
-	ctx   context.Context
-	ps    *pubsub.PubSub
-	topic *pubsub.Topic
-	sub   *pubsub.Subscription
+	ctx       context.Context
+	h         host.Host
+	ps        *pubsub.PubSub
+	chatTopic *pubsub.Topic
+	chatSub   *pubsub.Subscription
+	fileTopic *pubsub.Topic
+	fileSub   *pubsub.Subscription
 
 	roomName string
-	self     peer.ID
 	nick     string
 }
 
@@ -38,25 +44,39 @@ type ChatMessage struct {
 
 // JoinChatRoom tries to subscribe to the PubSub topic for the room name, returning
 // a ChatRoom on success.
-func JoinChatRoom(ctx context.Context, ps *pubsub.PubSub, selfID peer.ID, nickname string, roomName string) (*ChatRoom, error) {
-	// join the pubsub topic
-	topic, err := ps.Join(topicName(roomName))
+func JoinChatRoom(ctx context.Context, h host.Host, ps *pubsub.PubSub, nickname string, roomName string) (*ChatRoom, error) {
+	// join the pubsub chatTopic
+	chatTopic, err := ps.Join(chatTopicName(roomName))
 	if err != nil {
 		return nil, err
 	}
 
 	// and subscribe to it
-	sub, err := topic.Subscribe()
+	chatSub, err := chatTopic.Subscribe()
+	if err != nil {
+		return nil, err
+	}
+
+	// join the pubsub fileTopic
+	fileTopic, err := ps.Join(fileTopicName(roomName))
+	if err != nil {
+		return nil, err
+	}
+
+	// and subscribe to it
+	fileSub, err := fileTopic.Subscribe()
 	if err != nil {
 		return nil, err
 	}
 
 	cr := &ChatRoom{
 		ctx:         ctx,
+		h:           h,
 		ps:          ps,
-		topic:       topic,
-		sub:         sub,
-		self:        selfID,
+		chatTopic:   chatTopic,
+		chatSub:     chatSub,
+		fileTopic:   fileTopic,
+		fileSub:     fileSub,
 		nick:        nickname,
 		roomName:    roomName,
 		Messages:    make(chan *ChatMessage, ChatRoomBufSize),
@@ -70,23 +90,29 @@ func JoinChatRoom(ctx context.Context, ps *pubsub.PubSub, selfID peer.ID, nickna
 
 // Publish sends a message to the pubsub topic.
 func (cr *ChatRoom) Publish(message string) error {
-	return cr.topic.Publish(cr.ctx, []byte(message))
+	return cr.chatTopic.Publish(cr.ctx, []byte(message))
 }
 
 func (cr *ChatRoom) ListPeers() []peer.ID {
-	return cr.ps.ListPeers(topicName(cr.roomName))
+	return cr.ps.ListPeers(chatTopicName(cr.roomName))
 }
 
-// readLoop pulls messages from the pubsub topic and pushes them onto the Messages channel.
+// readLoop pulls messages from the pubsub chat/file topic and handles them.
 func (cr *ChatRoom) readLoop() {
+	go cr.readChatLoop()
+	go cr.readFileLoop()
+}
+
+// readChatLoop pulls messages from the pubsub chat topic and pushes them onto the Messages channel.
+func (cr *ChatRoom) readChatLoop() {
 	for {
-		msg, err := cr.sub.Next(cr.ctx)
+		msg, err := cr.chatSub.Next(cr.ctx)
 		if err != nil {
 			close(cr.Messages)
 			return
 		}
 		// only forward messages delivered by others
-		if msg.ReceivedFrom == cr.self {
+		if msg.ReceivedFrom == cr.h.ID() {
 			continue
 		}
 		cm := new(ChatMessage)
@@ -98,6 +124,73 @@ func (cr *ChatRoom) readLoop() {
 	}
 }
 
-func topicName(roomName string) string {
+// readFileLoop pulls messages from the pubsub file topic and handles them.
+func (cr *ChatRoom) readFileLoop() {
+	for {
+		msg, err := cr.fileSub.Next(cr.ctx)
+		if err != nil {
+			close(cr.Messages)
+			return
+		}
+		// only forward messages delivered by others
+		if msg.ReceivedFrom == cr.h.ID() {
+			continue
+		}
+
+		fileID := msg.Data
+		fileBody, err := cr.requestFile(msg.GetFrom(), fileID)
+		if err != nil {
+			close(cr.Messages)
+			return
+		}
+
+		cm := new(ChatMessage)
+		cm.Message = fmt.Sprintf("File: %s (%v bytes) from %s", string(fileID), len(fileBody), msg.GetFrom().String())
+		cm.SenderID = msg.ID
+		cm.SenderNick = string(msg.ID[len(msg.ID)-8])
+		// send valid messages onto the Messages channel
+		cr.Messages <- cm
+	}
+}
+
+func (cr *ChatRoom) requestFile(toPeer peer.ID, fileID []byte) ([]byte, error) {
+	stream, err := cr.h.NewStream(context.Background(), toPeer, "/universal-connectivity-file/1")
+	if err != nil {
+		return nil, fmt.Errorf("failed to create stream: %w", err)
+	}
+	defer stream.Close()
+
+	reqLen := binary.AppendUvarint([]byte{}, uint64(len(fileID)))
+	if _, err := stream.Write(reqLen); err != nil {
+		return nil, fmt.Errorf("failed to write fileID to the stream: %w", err)
+	}
+	if _, err := stream.Write(fileID); err != nil {
+		return nil, fmt.Errorf("failed to write fileID to the stream: %w", err)
+	}
+	if err := stream.CloseWrite(); err != nil {
+		return nil, fmt.Errorf("failed to close write stream: %w", err)
+	}
+
+	reader := bufio.NewReader(stream)
+	respLen, err := binary.ReadUvarint(reader)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read response length prefix: %w", err)
+	}
+	fileBody := make([]byte, respLen)
+	if _, err := reader.Read(fileBody); err != nil {
+		return nil, fmt.Errorf("failed to read fileBody from the stream: %w", err)
+	}
+	if err := stream.CloseRead(); err != nil {
+		return nil, fmt.Errorf("failed to close read stream: %w", err)
+	}
+
+	return fileBody, nil
+}
+
+func chatTopicName(roomName string) string {
 	return roomName
 }
+
+func fileTopicName(roomName string) string {
+	return fmt.Sprintf("%s-file", roomName)
+}

go-peer/main.go

@@ -78,7 +78,7 @@ func NewDHT(ctx context.Context, host host.Host, bootstrapPeers []multiaddr.Mult
 
 // Borrowed from https://medium.com/rahasak/libp2p-pubsub-peer-discovery-with-kademlia-dht-c8b131550ac7
 func Discover(ctx context.Context, h host.Host, dht *dht.IpfsDHT, rendezvous string) {
-	var routingDiscovery = routing.NewRoutingDiscovery(dht)
+	routingDiscovery := routing.NewRoutingDiscovery(dht)
 
 	discovery.Advertise(ctx, routingDiscovery, rendezvous)
 
@@ -198,7 +198,7 @@ func main() {
 	room := *roomFlag
 
 	// join the chat room
-	cr, err := JoinChatRoom(ctx, ps, h.ID(), nick, room)
+	cr, err := JoinChatRoom(ctx, h, ps, nick, room)
 	if err != nil {
 		panic(err)
 	}