// DisplayMessage responds with a disconnect message to the player
// when they attempt to connect to the server.
func DisplayMessage(s protocol.Stream, message string) error {
responsePacket := protocol.NewPacketWithID(0x00)
chatMessage := message
data, err := json.Marshal(chatMessage)
if err != nil {
return err
}
responsePacket.WriteString(string(data))
err = s.WritePacket(responsePacket)
return err
}
// WriteHandshakeResponse writes a response with a status that will be
// displayed on the requesting player's server list menu.
func WriteHandshakeResponse(s protocol.Stream, status Status) error {
statusResponse := statusResponse{
Version: version{
Name: "1lann/beacon " +
getReleaseName(status.ProtocolNumber),
Protocol: status.ProtocolNumber,
},
Players: players{
Max: status.MaxPlayers,
Online: status.OnlinePlayers,
},
Description: status.Message,
}
data, err := json.Marshal(statusResponse)
if err != nil {
return err
}
responsePacket := protocol.NewPacketWithID(0x00)
responsePacket.WriteString(string(data))
err = s.WritePacket(responsePacket)
return err
}
// ReadHandshakePacket reads a handshake packet (packet ID 0) and decodes it.
func ReadHandshakePacket(s protocol.Stream) (HandshakePacket, error) {
handshake := HandshakePacket{}
var err error
if handshake.ProtocolNumber, err = s.ReadVarInt(); err != nil {
return HandshakePacket{}, err
}
if handshake.ServerAddress, err = s.ReadString(); err != nil {
return HandshakePacket{}, err
}
if handshake.ServerPort, err = s.ReadUInt16(); err != nil {
return HandshakePacket{}, err
}
handshake.NextState, err = s.ReadVarInt()
return handshake, err
}
// HandlePingPacket handles a ping packet used by the Minecraft client
// used to measure the round trip time of the connection.
func HandlePingPacket(s protocol.Stream, status Status) error {
if !status.ShowConnection {
s.ReadInt64()
return nil
}
time, err := s.ReadInt64()
if err != nil {
return err
}
responsePacket := protocol.NewPacketWithID(0x01)
responsePacket.WriteInt64(time)
err = s.WritePacket(responsePacket)
return err
}