example server. close #61

cmd/simpleServer/main.go

@@ -0,0 +1,153 @@
+// Example minecraft 1.15.2 server
+package main
+
+import (
+	"github.com/Tnze/go-mc/bot"
+	"github.com/Tnze/go-mc/data"
+	"github.com/Tnze/go-mc/net"
+	pk "github.com/Tnze/go-mc/net/packet"
+	"github.com/google/uuid"
+	"log"
+)
+
+const ProtocolVersion = 578
+const Threshold = 256
+const MaxPlayer = 200
+
+func main() {
+	l, err := net.ListenMC(":25565")
+	if err != nil {
+		log.Fatalf("Listen error: %v", err)
+	}
+
+	for {
+		conn, err := l.Accept()
+		if err != nil {
+			log.Fatalf("Accept error: %v", err)
+		}
+		go acceptConn(conn)
+	}
+}
+
+func acceptConn(conn net.Conn) {
+	defer conn.Close()
+	// handshake
+	protocol, intention, err := handshake(conn)
+	if err != nil {
+		log.Printf("Handshake error: %v", err)
+		return
+	}
+
+	switch intention {
+	default: //unknown error
+		log.Printf("Unknown handshake intention: %v", intention)
+	case 1: //for status
+		acceptListPing(conn)
+	case 2: //for login
+		handlePlaying(conn, protocol)
+	}
+}
+
+func handlePlaying(conn net.Conn, protocol int32) {
+	// login, get player info
+	info, err := acceptLogin(conn)
+	if err != nil {
+		log.Print("Login failed")
+		return
+	}
+
+	// Write LoginSuccess packet
+	err = loginSuccess(conn, info.Name, info.UUID)
+	if err != nil {
+		log.Print("Login failed on success")
+		return
+	}
+
+	joinGame(conn)
+	conn.WritePacket(pk.Marshal(data.PlayerPositionAndLookClientbound,
+		// https://wiki.vg/Protocol#Player_Position_And_Look_.28clientbound.29
+		pk.Double(0), pk.Double(0), pk.Double(0), // XYZ
+		pk.Float(0), pk.Float(0), // Yaw Pitch
+		pk.Byte(0),   // flag
+		pk.VarInt(0), // TP ID
+	))
+	// Just for block this goroutine. Keep the connection
+	for {
+		if _, err := conn.ReadPacket(); err != nil {
+			log.Printf("ReadPacket error: %v", err)
+			break
+		}
+		// KeepAlive packet is not handled, so client might
+		// exit because of "time out".
+	}
+}
+
+type PlayerInfo struct {
+	Name    string
+	UUID    uuid.UUID
+	OPLevel int
+}
+
+// acceptLogin check player's account
+func acceptLogin(conn net.Conn) (info PlayerInfo, err error) {
+	//login start
+	var p pk.Packet
+	p, err = conn.ReadPacket()
+	if err != nil {
+		return
+	}
+
+	err = p.Scan((*pk.String)(&info.Name)) //decode username as pk.String
+	if err != nil {
+		return
+	}
+
+	//auth
+	const OnlineMode = false
+	if OnlineMode {
+		log.Panic("Not Implement")
+	} else {
+		// offline-mode UUID
+		info.UUID = bot.OfflineUUID(info.Name)
+	}
+
+	return
+}
+
+// handshake receive and parse Handshake packet
+func handshake(conn net.Conn) (protocol, intention int32, err error) {
+	var (
+		Protocol, Intention pk.VarInt
+		ServerAddress       pk.String        // ignored
+		ServerPort          pk.UnsignedShort // ignored
+	)
+	// receive handshake packet
+	p, err := conn.ReadPacket()
+	if err != nil {
+		return 0, 0, err
+	}
+	err = p.Scan(&Protocol, &ServerAddress, &ServerPort, &Intention)
+	return int32(Protocol), int32(Intention), err
+}
+
+// loginSuccess send LoginSuccess packet to client
+func loginSuccess(conn net.Conn, name string, uuid uuid.UUID) error {
+	return conn.WritePacket(pk.Marshal(0x02,
+		pk.String(uuid.String()), //uuid as string with hyphens
+		pk.String(name),
+	))
+}
+
+func joinGame(conn net.Conn) error {
+	return conn.WritePacket(pk.Marshal(data.JoinGame,
+		pk.Int(0),                  // EntityID
+		pk.UnsignedByte(1),         // Gamemode
+		pk.Int(0),                  // Dimension
+		pk.Long(0),                 // HashedSeed
+		pk.UnsignedByte(MaxPlayer), // MaxPlayer
+		pk.String("default"),       // LevelType
+		pk.VarInt(15),              // View Distance
+		pk.Boolean(false),          // Reduced Debug Info
+		pk.Boolean(true),           // Enable respawn screen
+	))
+}

cmd/simpleServer/status.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"encoding/json"
+	"github.com/Tnze/go-mc/chat"
+	"github.com/Tnze/go-mc/net"
+	pk "github.com/Tnze/go-mc/net/packet"
+	"github.com/google/uuid"
+	"log"
+)
+
+func acceptListPing(conn net.Conn) {
+	for i := 0; i < 2; i++ { // ping or list. Only accept twice
+		p, err := conn.ReadPacket()
+		if err != nil {
+			return
+		}
+
+		switch p.ID {
+		case 0x00: //List
+			err = conn.WritePacket(pk.Marshal(0x00, pk.String(listResp())))
+		case 0x01: //Ping
+			err = conn.WritePacket(p)
+		}
+		if err != nil {
+			return
+		}
+	}
+}
+
+type player struct {
+	Name string    `json:"name"`
+	ID   uuid.UUID `json:"id"`
+}
+
+// listResp return server status as JSON string
+func listResp() string {
+	var list struct {
+		Version struct {
+			Name     string `json:"name"`
+			Protocol int    `json:"protocol"`
+		} `json:"version"`
+		Players struct {
+			Max    int      `json:"max"`
+			Online int      `json:"online"`
+			Sample []player `json:"sample"`
+		} `json:"players"`
+		Description chat.Message `json:"description"`
+		FavIcon     string       `json:"favicon,omitempty"`
+	}
+
+	list.Version.Name = "Chat Server"
+	list.Version.Protocol = ProtocolVersion
+	list.Players.Max = MaxPlayer
+	list.Players.Online = 123
+	list.Players.Sample = []player{} // must init. can't be nil
+	list.Description = chat.Message{Text: "Powered by go-mc", Color: "blue"}
+
+	data, err := json.Marshal(list)
+	if err != nil {
+		log.Panic("Marshal JSON for status checking fail")
+	}
+	return string(data)
+}